1974 Special Assemblies of IAMAP-IAPSO: Report

IS

International Geophysics

1974 Special Assemblies of IAMAP-

IAPSO: Report

T

HE Special Assemblies of t h e I n t e r n a t i o n a l Association of Meteorology and A t m o s p h e r i c Phys­ ics and the I n t e r n a t i o n a l Association of Physical Sciences of t h e Oceans were held in M e l b o u r n e , Australia, from January 14 t o 2 5 , 1974. B o t h assemblies were well at­ tended. Of the a p p r o x i m a t e l y 5 0 0 delegates from 30 countries, 125 were from t h e United States, 22 were from Canada, and 2 were from Mex­ ico. T h e scientific program was excel­ lent and varied, and t h e Australian hosts provided a social program t h a t gave delegates and guests an oppor­ tunity t o sample t h e delights of their country—natural, historical, and fer­ mented. The scientific sessions included three Joint F r o n t i e r s sessions, c o m ­ posed of review papers, and t h e fol­ lowing: International Conference on Struc­ ture, Composition, and General Cir­ culation of the Upper and Lower Atmospheres and Possible Anthro­ pogenic Perturbations (UAPR C) Session 1: Aerosols (UAPRC-1) S e s s i o n 2: Aerosols a n d Gases (UAPRC-2) Session 3 : Gases (UAPRC-3) Session 4: O z o n e a n d Gases (UAPRC-4) Session 5: O z o n e (UAPRC-5) Session 6: O z o n e (UAPRC-6) Session 7: Meteorological Obser­ vations (UAPRC-7) Session 8: Variability (UAPRC-8) Session 9: Variability and T h e o r y (UAPRC-9) Session 10: T h e o r y ( U A P R C - 1 0 ) Session 11: Tracer Models (UAPRC-11) Session 12: Tracer Models (UAPRC-12) Session 13: Tracer and R a d i a t i o n Models (UAPRC-13)

Session 14: (UAPRC-14) Session 15: (UAPRC-15)

Radiation

Models

Radiation

Models

Meteorology of the Polar Regions (MPR) Session 1: Surface Wind Regime and Energy Budget (MPR-1) Session 2: R a d i a t i o n Balance and Atmospheric Circulation (MPR-2) Session 3: Polex Discussion (MPR-3) Meteorological Sessions (US) Session 1: S o u t h e r n Hemisphere Meteorology (US-1) S e s s i o n 2 : Upper Atmosphere Meteorology (US-2) Session 3: A t m o s p h e r i c Aerosols (US-3) Session 4 : A t m o s p h e r i c R a d i a t i o n (US-4) Session 5: B o u n d a r y Layer Mete­ orology (US-5) Session 6: Tropical Meteorology (US-6) Session 7: A t m o s p h e r i c Chemis­ try (US-7) Clouds sions)

and Radiation

(CR; Two Ses­

Meteorological-Biological tions at the Earth's Surface Sessions)

Interac­ (SB; Two

Symposium on Physical Oceanog­ raphy (PO) S e s s i o n 1: Large-Scale WindDriven Circulation (PO-1) S e s s i o n 2: T u r b u l e n c e , Eddies, a n d Diffusion (PO-2) Session 3 : ( n o title) (PO-3) S e s s i o n 4: T i d e s , F r o n t s , and A c o u s t i c s (PO-4) Session 5: Sea Surface (PO-5) Session 6: Water S t r u c t u r e (PO-6) Symposium on Ocean Waves (OW-I) Session 1: Wave D y n a m i c s and P r e d i c t i o n (OW-I-1)

Session 2: R e m o t e Sensing of Sea S t a t e (OW-I-2)

Symposium on Internal II; Two Sessions)

Waves (OW~

Symposium on Circulation and Long Waves (OW-III) S e s s i o n 1: Ocean Observations (OW-III-1) Session 2: T h e o r y of Circulation (OW-III-2) Session 3 : Long Waves (OW-III-3)

Symposium (ED; Two

Air-Sea

on Estuarine Sessions)

Interaction

Symposium

Dynamics

(AS)

Measurement and Prediction of Sea Surface Temperature (AS-I; Two Sessions) Mesoscale Phenomena in the Boundary Layers of the Ocean and the Marine Atmosphere (ASII; Two Sessions) Air-Sea Interaction in Synoptic and Climatic Development (AS-III; Three Sessions) Fluxes From Land and Sea Sur­ faces (AS-IV) S e s s i o n 1: Meso- a n d LargeScale F l u x e s (AS-IV-1) Session 2 : A t m o s p h e r i c Bound­ ary Layer (AS-IV-2) Session 3 : Direct M e a s u r e m e n t of F l u x e s and Wind S p e e d Near t h e Surface (AS-IV-3) Garp (G) Session 1: B o u n d a r y L a y e r Pa­ r a m e t e r i z a t i o n and Modeling (G-l) S e s s i o n 2 : N u m e r i c a l Modeling (G-2) Session 3 : G a t e (G-3) S e s s i o n 4 : Satellite T e c h n i q u e s (G-4) Symposium on Deep Convection (DC) Session 1: A t m o s p h e r e (DC-1) Session 2: G e o p h y s i c a l Fluid D y n a m i c s (DC-2) Session 3 : O c e a n (DC-3)

Abstracts of m o s t of t h e p a p e r s are available as a microfiche suppl­ e m e n t t o this r e p o r t . * T h e U.S. Delegates t o t h e assem­ blies a t t e m p t e d t o get r e p o r t s o n each session. T h e s e r e p o r t s , a l t h o u g h n o t a c o m p l e t e r e c o r d , have b e e n compiled here. E a c h r e p o r t is signed by its a u t h o r .

R e p o r t s o n t h e Sessions UAPRC-1: Aerosols T h e first speaker, C.E. J u n g e (West G e r m a n y ) , p r e s e n t e d a m o d e l describing t h e vertical profile of a e r o ­ sols above t h e t r o p o p a u s e . T h e p r o b ­ lem was a p p r o a c h e d by considering general conservation principles of stratospheric sulfur. Critical p o i n t s in developing t h e m o d e l include t h e assumed vertical profile and c o n c e n ­ t r a t i o n of S 0 above t h e t r o p o p a u s e and t h e effective reaction r a t e k t h a t is involved in converting S 0 to a sulfur-bearing aerosol. When it was possible, t h e assumed p a r a m e t e r val­ ues were justified from m e a s u r e d o r implied e x p e r i m e n t a l values; h o w ­ ever, very little is k n o w n of t h e value for k. F o r this reason t h e m o d e l was used t o predict a range of k b y making the resulting aerosol profile agree w i t h m e a s u r e d values. T h u s if t h e m o d e l is g o o d e n o u g h , t h e value of k can be c o m p a r e d w i t h m e a s u r e d reaction rates t o identify t h e r e a c t i o n itself. 2

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A n o t h e r p r e d i c t i o n of t h e m o d e l is t h a t t h e aerosol mixing ratio p r o ­ file would be of fixed shape b u t would move u p a n d d o w n w i t h t h e t r o p o p a u s e . T h i s fact seems t o be well f o u n d e d in t h e e x p e r i m e n t a l evidence p r e s e n t e d b y J.A. R o s e n (United States) for e q u a t o r i a l re­ gions. A t higher l a t i t u d e s , h o w e v e r , t h e aerosol mixing ratio profile is n o t clearly related t o t r o p o p a u s e height. This difference could possibly b e explained b y a d o m i n a n t e q u a t o r i a l source for t h e s t r a t o s p h e r i c aerosols. Results from m e a s u r e m e n t s of t h e isotopic ratio S / S p r e s e n t e d in a joint paper with H.R. Munkelwitz 3 2

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*Supplement is available with entire arti­ cle on microfiche. Order from American Geophysical Union, Suite 600, 1707 L Street, N.W., Washington, D.C. 20036. Document E74-002; $8.00. Payment must accompany order.

a n d B . M a n o w i t z b y A.W. Castleman J r . ( U n i t e d S t a t e s ) , indicate that the h i g h - a l t i t u d e aerosol comes from a c o m m o n e q u a t o r i a l source. This con­ clusion was based o n the similar t r e n d s of t h e S / S ratio observed in b o t h hemispheres. A n important p o i n t m a d e was t h a t it is the trends in t h e i s o t o p i c ratio t h a t are impor­ t a n t r a t h e r t h a n t h e value of the ratio itself. 3 2

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A . M ani (India) presented evi­ dence j o i n t l y with B.B. Huddar and C P . J o s e p h t h a t t h e electrical con­ d u c t i v i t y over P o o n a , India (18°N), is a p p a r e n t l y p e r t u r b e d toward lower values in t h e 18- t o 25-km region during t h e winter. These variations w e r e a t t r i b u t e d t o aerosols, but it was n o t clear w h e t h e r or not this is in a g r e e m e n t w i t h t h e seasonal fluct u a t i o n in aerosols reported by Rosen. R . Leifer ( U n i t e d States) pre­ s e n t e d s o m e n e w information con­ c e r n i n g t h e formation of strato­ spheric aerosols in t h e context of the p u b l i s h e d w o r k of J.P. Friend and his c o - w o r k e r s . E x p e r i m e n t a l evidence shows t h a t t h e f o r m a t i o n and stabil­ ity of sulfuric acid embryos are highly d e p e n d e n t o n the available w a t e r v a p o r c o n c e n t r a t i o n . A rela­ t i o n b e t w e e n t h e water vapor con­ c e n t r a t i o n a n d condensation nuclei c o n c e n t r a t i o n in a N H - S O - H 0 s y s t e m irradiated a t , short wave­ l e n g t h s was m e a s u r e d in the labora­ t o r y for a t m o s p h e r i c pressure and r o o m t e m p e r a t u r e . This relation has far-reaching consequences if it can be applied t o t h e actual stratosphere, b e c a u s e it p r e d i c t s relatively few con­ d e n s a t i o n nuclei for typical strato­ spheric w a t e r vapor concentrations. This is, of course, providing that t h e r e is n o o t h e r source of condensa­ tion nuclei. 3

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V a l u e s of t h e stratospheric aerosol c o n c e n t r a t i o n a n d profile obtained by an i m p a c t o r t e c h n i q u e were pre­ s e n t e d ( w i t h A . O n o ) b y E X Bigg (Australia) and c o m p a r e d with pro­ files o b t a i n e d b y R o s e n and his co­ w o r k e r s . F a v o r a b l e agreement was a p p a r e n t . U n d e r examination by the e l e c t r o n m i c r o s c o p e it was possible to c o n c l u d e t h a t o n some occasions t h e s t r a t o s p h e r i c particles were fro­ z e n liquid and o n other occasions t h e y w e r e n o t frozen. T h e impactor

samples show a relatively small number of particles b e l o w 0.1 /x in diameter, b u t this could b e owing t o low collection efficiencies for t h e smaller particles. J a m e s M. R o s e n University of Wyoming Laramie, Wyoming 8 2 0 7 0

UAPRC-2: Aerosols and Gases This IAMAP session d e a l t largely with particles and t r a c e gases in t h e stratosphere, a l t h o u g h s o m e d a t a for the t r o p o s p h e r e a n d m e s o s p h e r e were included. A paper b y R . D . C a d l e , E . F . Danielsen, A . Lazrus, B . G . Schuster, and J. Shedlovsky was largely a 'progress r e p o r t ' o n several studies of the stratospheric aerosol layer t h a t are being u n d e r t a k e n at t h e N a t i o n a l Center for A t m o s p h e r i c R e s e a r c h (NCAR). A d d i t i o n a l c o m p a r i s o n s have been m a d e of t h e collection efficiencies for s t r a t o s p h e r i c particles of impactors of t h e t y p e used b y Junge and his co-workers d u r i n g their stratospheric studies a b o u t fifteen years ago with t h e efficiencies of t h e polystyrene fiber filters b e i n g used at NCAR. The initial results, w h i c h showed that the impactors h a d at m o s t a b o u t 20% of t h e collection efficiency of the filters for s t r a t o s p h e r i c sulfuric acid particles, were c o n f i r m e d . T h e results also suggest t h a t t h e impac­ tors and filters collect a m m o n i u m sulfate, a m i n o r c o n s t i t u e n t of t h e aerosol, with a b o u t e q u a l efficiency. Probably t h e a m m o n i u m sulfate has a larger mean particle size t h a n t h e sulfuric acid. Calculations based o n t h e kinetic theory of gases show t h a t t h e possi­ bility of h e t e r o g e n e o u s chemical reactions involving s t r a t o s p h e r i c par­ ticles cannot readily b e dismissed. Furthermore, analyses of t h e watersoluble particulate m a t e r i a l in vol­ canic (Kilauea) e r u p t i o n clouds re­ vealed the presence of a large n u m b e r of trace m e t a l cations t h a t could enhance t h e catalytic activity of stratospheric particles. Samples collected o n filters flown on WB57F aircraft have b e e n ana­ lyzed for sulfate, a m m o n i u m , cal­ cium, magnesium, s o d i u m , chlorine, and bromine, w h i c h are in p a r t i c u l a t e

form, and nitric acid vapor, which is absorbed b y t h e filters. T h e flights extend from 7 5 ° N t o 5 1 ° S , and are flown 4 times annually at 4 t o 6 alti­ tudes b e t w e e n t h e t r o p o p a u s e and 2 0 k m . Filter samples are also being col­ lected by m e a n s of balloons flown at altitudes up to 27 k m . T h e mixing ratios of all t h e substances studied so far have had distributions t h a t t e n d to parallel t h e t r o p o p a u s e height. Their distributions are t h u s similar t o i s e n t r o p i c surfaces in t h e strato­ sphere. A paper by A. C o h e n a n d M. Graber described stratospheric a e r o ­ sol lidar m e a s u r e m e n t s over Jerusa­ lem. T h e y empahsized t h a t t o correct f o r m o l e c u l a r scattering using a standard a t m o s p h e r e can lead t o quite erroneous results. Variations in t h e molecular scattering p r o d u c e var­ iations t h a t can be confused w i t h a e r o s o l fluctuations. Cohen and Graber m a p p e d t h e aerosol layer w i t h scattering m e a s u r e m e n t s in t w o polarizations, determining changes in t h e n u m b e r density of particles as a function of t i m e . T h e y p o i n t e d o u t t h a t there are some t h i r t e e n lidar groups at present t h r o u g h o u t t h e world and strongly r e c o m m e n d e d greater cooperation a m o n g t h e m . T h e presentation b y V.M. Zakharov and six o t h e r a u t h o r s of t h e USSR was actually a r e p o r t of t h e work of t w o Soviet lidar groups. Like C o h e n and Graber, t h e y emphasized t h e i m p o r t a n c e of directly measuring t h e a m o u n t of molecular scattering if aerosol c o n c e n t r a t i o n profiles are t o be determined. This was achieved b y using lidar of t w o wavelengths. Mea­ surements were r e p o r t e d from b o t h Siberia and t h e Crimea. W. Seiler a n d U. S c h m i d t p r e ­ sented a paper entitled 'New Aspects o n t h e A t m o s p h e r i c C O - and H - c y c l e s ' t h a t was especially inter­ esting because new evidence—and conclusions—were presented bearing on t h e controversy concerning t h e sources of a t m o s p h e r i c CO a n d H . U n t i l the last few years carbon m o n o x i d e was t h o u g h t to be p r o ­ duced almost entirely by m a n . A t present, several groups of scientists believe, on t h e basis of isotopic CO data, that CO is mainly p r o d u c e d b y t h e p h o t o c h e m i c a l reaction of O H w i t h C H and is mainly d e s t r o y e d b y t h e oxidation of t h e CO w i t h O H . 2

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N e w data were p r e s e n t e d con­ cerning t h e latitudinal a n d h o r i z o n t a l d i s t r i b u t i o n in the t r o p o s p h e r e a n d lower stratosphere in b o t h hemi­ spheres a n d concerning t h e dissolved CO in sea water and r a i n w a t e r . L o w e r CO c o n c e n t r a t i o n s w e r e f o u n d in t h e air of t h e s o u t h e r n h e m i s p h e r e t h a n in t h e air of t h e n o r t h e r n h e m i ­ sphere, a n d s o u t h of 4 0 ° S t h e con­ c e n t r a t i o n was c o n s t a n t in all d i m e n ­ sions b e l o w t h e t r o p o p a u s e . T h e a u t h o r s concluded t h a t t h e rates of both photochemical production and p h o t o c h e m i c a l d e s t r u c t i o n of CO have r e c e n t l y been greatly overesti­ m a t e d . Possibly t h e a n t h r o p o g e n i c and p h o t o c h e m i c a l p r o d u c t i o n and d e s t r u c t i o n are a b o u t equally i m p o r ­ tant. A l s o , n e w data c o n c e r n i n g t h e H distribution in t h e t r o p o s p h e r e a n d lower stratosphere were presented and discussed. Again, a n i m p o r t a n t result was t h e higher m i x i n g ratio in t h e n o r t h e r n h e m i s p h e r e . The a u t h o r s concluded t h a t a n t h r o p o ­ genic H p r o d u c t i o n is a b o u t 6 0 % of t h e t o t a l H p r o d u c t i o n in t h e t r o p o ­ sphere, t h a t t h e oceans are always a source of H , and t h a t t h e m e a n a t m o s p h e r i c residence t i m e is 7—8 years. 2

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I n 1968 E . A . Martell a n d his co­ w o r k e r s l a u n c h e d a successful flight of a cryogenic sampler t h a t collected a large sample of air from t h e u p p e r s t r a t o s p h e r e and l o w e r m e s o s p h e r e . T h e analyses of this sample have been r e p o r t e d in a n u m b e r of publi­ cations. A t this m e e t i n g Martell re­ p o r t e d t h e results from a second successful flight, w i t h a modified ver­ sion of t h e sampler, m a d e in May 1 9 7 3 . T h e c o n s t i t u e n t s either mea­ sured or in process of m e a s u r e m e n t include C 0 , H 0 , C H , H , N 0 , and C O . Martell discussed t h e p r o ­ d u c t i o n of w a t e r vapor in t h e strato­ sphere a n d mesosphere by t h e oxida­ tion of m e t h a n e and b y h y d r o g e n in view of his results a n d t h o s e o b t a i n e d by E h h a l t and Heidt w i t h balloon sampling. 2

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R i c h a r d D. Cadle

N a t i o n a l C e n t e r for A t m o s p h e r i c Research Boulder, Colorado 80302

UAPRC-3: Gases This session was d e v o t e d t o recent m e a s u r e m e n t s of t r a c e c o n s t i t u e n t s of t h e s t r a t o s p h e r e . T h e first paper of t h e session was given b y H J . Maste n b r o o k a n d described t h e results of his extensive m e a s u r e m e n t s of strato­ spheric w a t e r vapor. T h e s e m e a s u r e m e n t s , w h i c h are made w i t h a balloon-borne a u t o m a t i c frost p o i n t h y d r o m e t e r , c o n t a i n t h e only stratospheric w a t e r vapor data t h a t have b e e n m a d e o n a fairly r o u ­ tine basis over an e x t e n d e d period of time. T h e m e a s u r e m e n t s indicated a gradual increase in t h e w a t e r vapor mixing ratio over Washington, D . C , in t h e l o w e r stratosphere during t h e first six years of o b s e r v a t i o n ; h o w ­ ever, t h i s t r e n d was b r o k e n in 1970, a n d m e a s u r e m e n t s in t h e early 1970's are again in t h e 2-ppm by weight r a n g e . M a s t e n b r o o k has l o o k e d for possi­ ble causes of t h e decrease and sug­ gested as a possibility a decrease in t h e t r o p o p a u s e t e m p e r a t u r e in t h e tropics observed several years earlier over Singapore. T h e s e c o n d paper, b y W.F.J. Evans, described r o c k e t - b o r n e mea­ s u r e m e n t s of water vapor. T h e water vapor m i x i n g ratio was d e t e r m i n e d from infrared solar spectra obtained during sunset. T h e mixing ratio de­ t e r m i n e d for t h e 20- t o 3 0 - k m range in this e x p e r i m e n t was 3—4 p p m by volume. P. H y s o n described a series of water v a p o r m e a s u r e m e n t s made in t h e s o u t h e r n h e m i s p h e r e . Observa­ tions w e r e m a d e w i t h an infrared r a d i o m e t e r operating in t h e water vapor r o t a t i o n a l b a n d . M e a s u r e m e n t s were m a d e b y using t w o different elevation l o o k angles, w h i c h should have eliminated any local c o n t a m i n a ­ tion effects. T h e results obtained during several ascents a n d descents w e r e p r e s e n t e d . T h e d a t a showed very large variability, n o t o n l y from day t o d a y , b u t also b e t w e e n ascent and d e s c e n t . T h e reviewer believes t h e results reflect t h e difficulty of interpreting data o b t a i n e d w i t h wide­ band radiometers. R . C W h i t t e n p r e s e n t e d some re­ sults o b t a i n e d b y investigators at NASA A m e s R e s e a r c h L a b o r a t o r i e s on t h e s i m u l t a n e o u s m e a s u r e m e n t of N O a n d 0 . M e a s u r e m e n t s were m a d e f r o m a U-2 aircraft. T h e NO 3

results o b t a i n e d during t w o flights were in t h e range 0 . 2 - 0 . 3 p p b b y volume for N O . T h e N O did n o t appear t o vary w i t h t h e 0 v a r i a t i o n along t h e flight p a t h at 21 k m ; h o w ­ ever, data have only b e e n o b t a i n e d for a limited n u m b e r of flights, a n d it is early t o draw a n y c o n c l u s i o n s o n possible correlations of t h e d a t a . H.-J. Bolle p r e s e n t e d d a t a c o n ­ cerning t h e d i s t r i b u t i o n of w a t e r vapor with a l t i t u d e o b t a i n e d f r o m analysis of t h e 2.7-ju a b s o r p t i o n o b ­ served in sunset solar spectra o b ­ tained from a b a l l o o n . T h e profile was relatively moist (>1CT gram H 0 / g r a m air) at 30 k m . H o w e v e r , the fact t h a t t h e profile was o b t a i n e d from sunset spectra eliminates t h e possibility t h a t t h e m e a s u r e m e n t s were c o n t a m i n a t e d . T h e spectral re­ gion covered in t h e m e a s u r e m e n t s were c o n t a m i n a t e d . T h e spectral re­ gion covered in t h e m e a s u r e m e n t s also included t h e 3.3-jU C H band. N o profile was p r e s e n t e d ; h o w e v e r , t h e m e a s u r e m e n t s indicated a signifi­ cant decrease in t h e m e t h a n e m i x i n g ratio above t h e t r o p o p a u s e , in agree­ m e n t w i t h o t h e r observations. J . E . Harries discussed t h e farinfrared a t m o s p h e r i c m e a s u r e m e n t program of t h e N a t i o n a l Physical L a b o r a t o r y . This p r o g r a m i n c l u d e s a significant l a b o r a t o r y effort, since laboratory data are often n o t avail­ able for m a n y of t h e m o l e c u l e s of atmospheric i n t e r e s t . T h e m e a s u r e ­ m e n t program includes o b s e r v a t i o n s over a wide range of l a t i t u d e a n d longitude. Analysis has b e e n c o m ­ pleted o n s o m e of t h e data, a n d an altitude profile was p r e s e n t e d for N 0 t h a t was in close a g r e e m e n t with t h a t given b y Goldman et al [ 1 9 7 3 ] . A n average mixing r a t i o for N0 has also b e e n d e t e r m i n e d as­ s u m i n g the N 0 was u n i f o r m l y mixed above t h e aircraft a l t i t u d e ( 1 5 k m ) . T h e value p r e s e n t e d was 2.5 p p b by v o l u m e . D.G. Murcray p r e s e n t e d m i x i n g ratio profiles for a n u m b e r of consti­ t u e n t s d e t e r m i n e d from several bal­ loon flights w i t h various infrared i n s t r u m e n t s . Profiles were p r e s e n t e d for H 0 , H N 0 , and N 0 . T h e water vapor results were based o n atmospheric emission m e a s u r e m e n t s . T h e t w o profiles p r e s e n t e d f o r H o l l o m a n Air F o r c e Base ( l a t i t u d e 3 2 ° ) indicated a significant increase in t h e 3

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2

w a t e r v a p o r mixing ratio above 30 k m (mixing ratio 4 - 6 X I d H 0 / g r a m air). A third profile for F a i r b a n k s , Alaska, did not show this increase. All profiles gave mixing r a t i o s j u s t above t h e tropopause of a r o u n d 10" gram H 0 / g r a m air. Several H N 0 profiles were p sented for H o l l o m a n and Alaska. The A l a s k a n profiles showed a signifi­ c a n t l y higher H N 0 mixing ratio t h a n was observed at Holloman, An N0 profile d e t e r m i n e d from infra­ red solar spectra obtained from 30 k m at sunset was also presented. The profile s h o w e d a rapid increase in m i x i n g r a t i o w i t h altitude above 16 k m , increasing from 0.4 ppb by vol­ u m e at 16 k m t o 5.0 p p b at 29 km. 6

g r a m

2

6

2

3

re

3

2

Reference Goldman, A., D.G. Murcray, F.H. Mur­ cray, and W.J. Williams, Balloon-borne infrared measurements of the vertical distribution of N O in the atmosphere, /. Opt. Soc. Amer., 63, 843, 1973. 2

D.G. Murcray Denver Research Institute University of Denver Denver, Colorado 80210

UAPRC-7: Meteorological Observations T h e session o n Meteorological O b s e r v a t i o n s ( c h a i r m a n , J.B. Greg­ o r y ) w a s largely concerned with the u p p e r a t m o s p h e r e , principally in the s o u t h e r n h e m i s p h e r e . Five of eight s c h e d u l e d p a p e r s were presented, and t h e y revealed an interesting diversity of t e c h n i q u e s for analyzing the radiat i o n a l , t h e r m a l , a n d circulation re­ gimes at high altitudes. T h e o p e n i n g p a p e r , by R.N. Kulk a r n i , was o n t h e use of groundbased n i g h t g l o w observations at 5577 k for inferring features of the circu­ l a t i o n of t h e u p p e r mesosphere and lower t h e r m o s p h e r e . This capability was b a s e d o n t h e assumption that the o b s e r v e d m o t i o n of isophotes is re­ lated t o m o t i o n s of t h e neutral atmo­ s p h e r e , t h e airglow emission being f r o m n e u t r a l o x y g e n atoms. Night sky o b s e r v a t i o n s at DeniUquin, Aus­ tralia ( 3 3 ° S , 1 4 5 ° E ) , were combined w i t h d a t a from o t h e r mid-latitude sites of t h e s o u t h e r n hemisphere to

obtain a comprehensive view of t h e variability of I $ sm­ ite next t w o p a p e r s w e r e novel in their use of satellite infrared radia­ tion measurements for describing thermal waves a n d for inferring t h e stratospheric circulation s t a t e during the southern h e m i s p h e r e w i n t e r . R . S . Quiroz showed h o w satellite data such as those m e a s u r e d b y t h e satel­ lite infrared s p e c t r o m e t e r s a n d verti­ cal temperature profile r a d i o m e t e r s may be used t o describe t h e full range of stratospheric w a r m i n g activ­ ity in the southern hemisphere., Using direct regression t e c h n i q u e s , in con­ trast to inversion s o l u t i o n s for t e m ­ perature, he d e d u c e d t h e r m a l a n d circulation changes t h a t were inde­ pendently verified b y r o c k e t observa­ tions at t h e Soviet s t a t i o n at Molodezhnaya ( 6 8 ° S ) . W i t h t h e aid of h e m i s p h e r i c r a d i a n c e m a p s he showed how t h e s u p e r p o s i t i o n of eastward-traveling and s t a n d i n g t h e r ­ mal waves m a y lead t o significant stratospheric warmings, although none of t h e events o b s e r v e d in 1969-1973 were of sufficient magni­ tude to achieve a reversal of t h e wintertime polar c i r c u l a t i o n in t h e lower stratosphere. The next paper, b y R . S . H a r w o o d (Oxford University, U . K . ) , l o o k e d further into t h e s t r u c t u r e of t h e t e m ­ perature waves and p r o v i d e d a t a n ­ talizing glimpse i n t o t h e energetics of the s o u t h e r n h e m i s p h e r e strato­ sphere. B y F o u r i e r analysis, h e showed t h e d o m i n a n c e of wave n u m ­ ber 2 in t h e radiance fields for late S e p t e m b e r 1 9 7 1 , using selective chopper radiometer m e a s u r e m e n t s in the four ' u p p e r ' channels of t h a t in­ strument. Monitoring of t h e data for 1971 showed an eastward-traveling wave that could be t r a c k e d for nearly two months. R a d i a n c e c e n t e r s in t h e highest and lowest c h a n n e l s were in antiphase and indicated a w e s t w a r d slope with height of t h e associated thermal systems. A m p l i f i c a t i o n of waves in t h e u p p e r s t r a t o s p h e r e could largely be related t o behavior in the lower s t r a t o s p h e r e , a n d calcu­ lations of zonal and e d d y available potential energy suggested t h a t t h e required energy was p r o v i d e d from below (kinetic energies c o u l d n o t b e evaluated owing t o t h e lack of wind data).

T h e fourth p a p e r of this session, by J.E. L a b y a n d E X . U n t h a n k (Mel­ b o u r n e University), was devoted t o an analysis of w i n d variability in t h e 30- t o 45-km region, based mainly o n very high altitude radar-tracked bal­ loon flights, 1 9 6 7 - 1 9 7 1 , at t h r e e sites in Australia. Several periods of stratospheric easterlies were observed in winter at Laverton ( 3 8 ° S ) , disturb­ ing t h e n o r m a l westerly flow, and these were considered t o b e associ­ ated with stratospheric warmings at higher latitudes. Comparisons were m a d e w i t h high-altitude winds for the northern hemisphere and with rocket winds at W o o m e r a , Australia. F r o m t h e latter, large wind variations were deduced at 35 k m over a longi­ t u d e separation of a b o u t 15°. T h e final p a p e r , by K. Sekihara, M. K a n o , and M. Miyauchi ( M e t e o r o ­ logical Research I n s t i t u t e , T o k y o ) , d e s c r i b e d observations of o z o n e , d o w n w a r d radiation flux, a n d w a t e r vapor mixing r a t i o above t h e 10-km level, c o n d u c t e d at t h r e e J a p a n e s e sites mainly in 1 9 7 1 - 1 9 7 2 . T h e o r e t ­ ical radiation fluxes were calculated and compared w i t h observed values. As s o m e of t h e results appeared t o b e influenced by observational error, Dr. Sekihara emphasized t h e n e e d for closer c o o r d i n a t i o n w i t h t h e observa­ tional staff. R.S. Quiroz National Meteorological Center, N O A A 5200 Auth Road Washington, D.C. 2 0 0 2 3

UAPRC-8: Variability This session c o n c e n t r a t e d exclu­ sively o n t h e m e a s u r e m e n t of n e u t r a l winds in t h e u p p e r mesosphere a n d lower t h e r m osphere. T h e first paper, given b y C H . L o w and A . D . Hind (Australia), de­ tailed the first m e a s u r e m e n t s ever m a d e t h a t have p r o d u c e d w i n d p r o ­ files for t h e height range 90—130 k m d u r i n g daylight h o u r s using t h e rocket-released chemical trail t e c h ­ n i q u e . Three releases, one 2 h o u r s after sunrise, o n e at m i d d a y , and o n e in the afternoon (all on separate days) were observed from t h e g r o u n d

by using scanner s y s t e m s with 2-A filters c e n t e r e d on t h e l i t h i u m r e s o ­ n a n t scattering line. Triangulation of simultaneously r e c o r d e d rasters f r o m t w o sites p r o d u c e d h o r i z o n t a l w i n d profiles w i t h b e t t e r t h a n 1-km height r e s o l u t i o n . T h e r o t a t i o n of t h e w i n d vector w i t h height, characteristic of a tidal w i n d p a t t e r n similar t o t h a t o b ­ served in t h e m o r e r o u t i n e twilight a n d n i g h t releases, is also evident in t h e d a y t i m e profiles. T h e n e x t t w o p a p e r s were pre­ sented as o n e by J . B . Gregory a n d A.H. M a n s o n ( C a n a d a ) , w h o o u t l i n e d t h e h i s t o r y of t h e partial-reflections drift t e c h n i q u e and p r e s e n t e d results showing t h e p r o p a g a t i o n of gravity waves t h r o u g h t h e 8 5 - t o 105-km h e i g h t range, w i t h vertical wave­ lengths of s o m e 2 0 k m a n d periods of a p p r o x i m a t e l y 1 h o u r , with a greater incidence in w i n t e r t h a n in s u m m e r . Prevailing w i n d s also m e a ­ sured (at S a s k a t o o n , 5 2 ° N ) w e r e f o u n d t o agree well w i t h t h e Groves m o d e l (Cira 1973). T h e following p a p e r , b y B.H. Briggs, T.J. S t u b b s , a n d R . A . V i n c e n t (Australia), p r e s e n t e d b y V i n c e n t , detailed c o m p a r i s o n s m a d e b e t w e e n partial reflection drifts and radio m e t e o r winds as m e a s u r e d at A d e ­ laide ( 3 1 ° S ) . With b o t h sets of data subjected t o t h e same analysis t e c h ­ niques, agreement is excellent, as is t h a t w i t h rocket-released d r o p s o n d e data in t h e lower m e s o s p h e r e . T h e t e m p o r a l r e s o l u t i o n of t h e partialreflections drift t e c h n i q u e is s u c h t h a t w i n d reversals have been o b ­ served t o occur w i t h i n a 10-min period. This p a p e r was beautifully c o m ­ p l e m e n t e d b y t h a t of W.G. Elford and S.A. Y o u n g (Australia), w h o p r e ­ sented a detailed analysis of 6 years of radio m e t e o r wind d a t a , also f r o m A d e l a i d e . T h e m o s t o u t s t a n d i n g fea­ t u r e of t h e s e results was t h e definite change in prevailing w i n d regimes at 85—90 k m , w i t h a ' m o n s o o n a F m e s o spheric circulation b e l o w a n d a de­ cidedly different t h e r m o s p h e r i c cir­ c u l a t i o n a b o v e . More p o w e r t o t h o s e w h o w o u l d like to see 9 0 k m used as t h e lower b o u n d a r y for t h e r m o ­ spheric m o d e l s ! Also of interest was a m e a n w i n d height gradient reversal in 1969 w i t h 1 9 7 3 results apparently r e t u r n i n g t o t h e p r e - 1 9 6 9 t r e n d s , for

which n o e x p l a n a t i o n is o b v i o u s . T h e tidal d a t a in this set s h o w e d com­ patibility of seasonal averages, al­ t h o u g h day t o day variability was high. T h e n e x t paper, b y R . G . R o p e r (United States), concentrated on the variability of vertical diffusivities in the n e i g h b o r h o o d of t h e t u r b o p a u s e , while a t t e m p t i n g t o delineate vertical diffusivity profiles t h a t m i g h t be of use particularly in t h e m o d e l i n g of the c o m p o s i t i o n of t h e l o w e r therm o s p h e r e . T h e efficacy of advection over vertical diffusion as a transport m e c h a n i s m was e m p h a s i z e d . T h e following p a p e r , by K.H. Lloyd (Australia), p r e s e n t e d some very convincing a r g u m e n t s against interpreting t h e obviously t u r b u l e n t s t r u c t u r e , particularly o n sodium vapor trails, as a m b i e n t t u r b u l e n c e only. Calculations of release ener­ getics p o i n t t o t h e trail s t r u c t u r e as being p r o d u c e d b y t h e b u o y a n c y of the released material. T h i s interpreta­ tion is reinforced b y t h e appearance of w h a t can best be described as b u o y a n t p l u m e s on s o m e releases. The a u t h o r was quick t o p o i n t out that his observations do s h o w local­ ized a m b i e n t t u r b u l e n c e t o be pres­ ent, b u t he believes t h a t large-scale eddy mixing, r a t h e r t h a n classical small-scale t u r b u l e n c e , is responsible for t h e vertical diffusivity r e q u i r e d t o satisfy c o n s t i t u e n t m e a s u r e m e n t s and heat b u d g e t calculations. J . D . W o o d s ( E n g l a n d ) , a n IAPSO delegate, p o i n t e d o u t d u r i n g discus­ sion of this p a p e r t h a t w h a t are really needed t o settle all a r g u m e n t s on tur­ bulence are m e a s u r e m e n t s of the a m b i e n t t e m p e r a t u r e s t r u c t u r e . Mea­ surements of t e m p e r a t u r e profiles w i t h 100-m resolution are eagerly awaited b y t u r b o p a u s e dynamicists. R.G. Roper School of Aerospace Engineering Georgia I n s t i t u t e of T e c h n o l o g y A t l a n t a , Georgia 3 0 3 3 2

UAPRC-9: Variability and Theory T h e session o p e n e d w i t h a review, including m a n y n e w results, of plane­ tary scale waves in t h e s t r a t o s p h e r e a n d m e s o s p h e r e , b y R J . Deland

(United S t a t e s ) . T h e presence of such waves, particularly traveling waves, has b e e n tentatively suggested b y D and E region a e r o n o m e r s as a possi­ ble e x p l a n a t i o n of drift a n d ioniza­ tion anomalies. T h a t m e t e o r o l o g i s t s are providing evidence of t h e pres­ ence of these waves at m e s o s p h e r i c altitudes is i n d e e d gratifying. These results were r e i n f o r c e d b y t h e p r e s e n t a t i o n b y I. H i r o t a ( J a p a n ) , p a r t i c u l a r l y since his analysis of northern hemisphere MRN data pro­ d u c e s w a v e s w i t h periodicities ( 1 0 - 1 5 days) a n d vertical s t r u c t u r e ( ~ 1 5 k m ) similar t o t h o s e observed in t h e m e t e o r region. S o m e higher-latitude r o c k e t t e m ­ perature a n d density data of Y u . P . Koshelkov ( U S S R ) were s u m m a r i z e d briefly b y A . Khrgian ( U S S R ) . This was followed b y a p a p e r b y A . D . Bel­ m o n t , D.G. D a r t t , and G.D. N a s t r u m (United S t a t e s ) , w h o p r e s e n t e d s o m e convincing a r g u m e n t s for possible geomagnetic influence o n long-term p e r i o d i c i t i e s (annual, semiannual, and possibly t e r a n n u a l ) in t h e s t r a t o ­ spheric zonal w i n d t h a t e x h i b i t lati­ tudinal a s y m m e t r y in g e o g r a p h i c , b u t n o t geomagnetic c o o r d i n a t e s . Bel­ m o n t inferred t h a t particle p r e c i p i t a ­ tion if t h e a u r o r a l zones m a y p l a y a significant p a r t even in s t r a t o s p h e r i c dynamics. Consideration was t h e n given t o global i n t e r a c t i o n s in s t r a t o s p h e r e and t r o p o s p h e r e by A . B . P i t t o c k (Australia), w h o used o z o n e as a tracer. Midlatitude a n d p o l a r t o t a l o z o n e was f o u n d t o be influenced m a r k e d l y b y t r o p o s p h e r i c midlatitude m e t e o r o l o g y a n d t o be par­ ticularly d e p e n d e n t o n t h e critical l a t i t u d e for t h e onset of baroclinic ^ s t a b i l i t y . D u r i n g t h e discussion it was p o i n t e d o u t t h a t this is o n e area of investigation in which, c o n t r a r y t o t h e conclusions of R.W. S t e w a r t ' s Garp frontiers p r e s e n t a t i o n , t h e o r y will have t o p r e c e d e data availability. In t h e p a p e r b y G.J. B o e r , R . E . N e w e l l , a n d J.W. K i d s o n , B o e r ( U n i t e d States) p r e s e n t e d a m o d e l of t h e lower a t m o s p h e r e derived f r o m t h e so-called e x a c t e q u a t i o n s a n d from long-term, seasonally averaged data. T h e m o d e l s h o w s p r o m i s e b u t requires a b e t t e r k n o w l e d g e of t h e long-term d y n a m i c s of vertical e d d y t r a n s p o r t . T h e session c o n c l u d e d

w i t h an u n s c h e d u l e d presentation on m o m e n t u m transfer by waves by M.E. M c l n t y r e (United Kingdom), w i t h particular reference to the inter' a c t i o n of waves w i t h t h e zonal flow a n d a r e f o r m u l a t i o n of the theory of B r e t h e r t o n in Lagrangian terms. R . G . Roper

S c h o o l of A e r o s p a c e Engineering Georgia I n s t i t u t e of Technology A t l a n t a , Georgia 3 0 3 3 2

UAPRC-9: Variability and Theory R . J . Deland, using SIRS-A radi­ ances a n d V L F radio data, employed z o n a l F o u r i e r analysis to describe the a m p l i t u d e and phase of traveling waves a n d their phase shifts with height at l a t i t u d e s from 60°S to 6 0 N . I n winter, waves tilt westward w i t h height where zonal westerlies in­ crease w i t h height and tilt eastward w h e r e westerlies decrease with height in t h e l o w e r s t r a t o s p h e r e . This is con­ sistent w i t h conversion of energy from z o n a l flow t o t h e waves. The phases of traveling waves in the iono­ sphere indicate t h a t similar relations hold u p to 80 k m . I . H i r o t a f o u n d oscillations of 10—15 days in t h e subtro pics above 3 0 k m during t h e summer, using spectra of t e m p e r a t u r e and wind f r o m m e t e o r o l o g i c a l rocket and V T P R satellite d a t a . F u r t h e r analyses i n d i c a t e t h a t t h e oscillation as re­ vealed b y t h e t i m e series analysis for individual observation stations is a re­ flection of t h e h o r i z o n t a l movement of p l a n e t a r y waves embedded in the s u m m e r m e s o s p h e r e easterlies. The east-west wave n u m b e r is estimated as 2 o r 3 , a n d t h e vertical wavelength is close t o 15 k m . T h e wave ampli­ t u d e increases w i t h increasing height in t h e s t r a t o s p h e r e , b u t t h e wave en­ ergy d e n s i t y decreases with height, i n d i c a t i n g t h a t t h e wave is an evanes­ cent m o d e . A brief s u m m a r y of a paper on seasonal c o m p a r i s o n s of the thermal fields of t h e arctic and antarctic s t r a t o s p h e r e s b y Y u . P. Koshelkov was r e a d . T h e a n t a r c t i c thermal field is w a r m e r t h a n t h e arctic from 30 to 5 0 k m in m i d w i n t e r and spring. The a n t a r c t i c a n d arctic difference in s u m m e r is small, b u t in autumn and

early winter t h e a n t a r c t i c is colder than the arctic. T h e r e g i o n f r o m 5 0 to 60 km is colder in t h e a n t a r c t i c all year, but n o differences w e r e f o u n d from 65 to 80 k m . P r e s s u r e a n d d e n ­ sity values in b o t h s t r a t o s p h e r e a n d mesosphere are 2 5 - 4 0 % l o w e r in t h e antarctic in t h e w i n t e r , b u t are c o m ­ parable in summer. Suggested reasons for t h e n o r t h south asymmetries in p a t t e r n s of amplitude of t h e a n n u a l , s e m i a n n u a l , and terannual waves in s t r a t o s p h e r i c zonal wind were given b y A . D . Bel­ mont, D.G. D a r t t , a n d G . D . N a s t r o m , as well as a suggested cause for t h e polar semiannual wave. T h e s t r a t o ­ spheric annual wave m a y have its minimum n o r t h of t h e e q u a t o r be­ cause of t h e 7% less r a d i a t i o n re­ ceived by t h e o z o n e l a y e r in t h e northern hemisphere s u m m e r c o m ­ pared with t h e s o u t h e r n h e m i s p h e r e summer owing t o v a r i a t i o n s in sunearth distance. T h e p o l a r s e m i a n n u a l wave may be due t o s e m i a n n u a l geomagnetic activity, w h i c h t h r o u g h ionization u l t i m a t e l y influences ozone concentration near 7 0 k m a n d thereby t h e t h e r m a l field. T h e t r o p i ­ cal semiannual wave c o i n c i d e s b e t t e r with the geomagnetic r a t h e r t h a n t h e geographic e q u a t o r , w h i c h also m a y be due t o t h e effect of a u r o r a l par­ ticle precipitation. An extensive discussion was given by A.B. Pittock of t h e c o r r e l a t i o n s of the latitude of t h e surface highpressure belt L w i t h s t r a t o s p h e r i c ozone, t e m p e r a t u r e , and wind. T h e 'southern oscillation' is also related to variations of t o t a l o z o n e , t e m p e r a ­ ture, and rainfall over large areas of the North and S o u t h Pacific. It was suggested that L i n d i c a t e s intensity of the mean Hadley cell a n d t h a t t h e s o u t h e r n oscillation reflects t h e a s y m m e t r y b e t w e e n e a s t e r n and western hemispheres. Computation of t h e energy cycle of the entire global a t m o s p h e r e ( b o t h hemispheres), for each of four sea­ sons of long-term averaged data, at levels below 100 m b a r w a s reviewed by G J . Boer, R.E. N e w e l l , and J.W. Kidson, who explained t h e present difficulties of such s t u d i e s w i t h examples of t h e sensitivity of t h e cal­ culations t o assumed d i s t r i b u t i o n of various parameters.

A n added p a p e r by M. M c l n t y r e and J.C. A n d r e w s presented a more rational t h e o r y for t h e effects of wave p r o p a g a t i o n o n a z o n a l current. A.D. Belmont C o n t r o l Data C o r p o r a t i o n Minneapolis, Minnesota 5 5 4 2 0

UAPRC-10: Theory T h e first p a p e r in this very inter­ esting session was presented b y A.J. S i m m o n s (United K i n g d o m ) , w h o discussed planetary-scale quasi-geostrophic disturbances in t h e polar winter stratosphere. This study has to be one of t h e most significant in this area in t h e past few years. It laid to rest m a n y m i s c o n c e p t i o n s and clarified our u n d e r s t a n d i n g of t h e dynamics of these disturbances. S i m m o n s considered t h e structure of these waves w h e n t h e y are super­ imposed on a simple b u t realistic r e p r e s e n t a t i o n of t h e w i n t e r t i m e zonal flow s t r u c t u r e of the strato­ sphere. T h e y were assumed t o be forced at t h e t r o p o p a u s e level b y some k n o w n disturbance. He found excellent agreement w i t h observa­ tions o n t h e stationary wave struc­ ture w i t h o u t having t o invoke n o n ­ l i n e a r effects, as was previously t h o u g h t necessary. Again in accord with observations, S i m m o n s f o u n d t h a t m a x i m u m forced wave ampli­ tudes t e n d e d t o occur near regions of m a x i m u m westerly flow, i.e., t h e polar night j e t . Prior studies h a d a n t i c i p a t e d significant ducting of w a v e energy away from t h e j e t toward t h e equatorial z e r o wind line. S i m m o n s concluded t h a t t h e n o r t h south curvature of the z o n a l flow, w h i c h was neglected in previous studies, was a m o s t i m p o r t a n t p a r a m ­ eter. I n considering t h e response t o t i m e - d e p e n d e n t forcing, S i m m o n s found t h a t a rapidly growing highlevel disturbance resulted from lowlevel baroclinic conversion of p o t e n ­ t i a l e n e r g y and the subsequent upward t r a n s p o r t of t h e converted energy. He suggested t h a t t h e rapidly growing disturbance associated w i t h t h e stratospheric warming is simply a response t o e n h a n c e d t r o p o s p h e r i c forcing and n o t due t o t h e strato­

spheric z o n a l flow t a k i n g on some special configuration. A second paper, by B.G. H u n t (Australia), was mainly a description of a primitive e q u a t i o n m o d e l at t h e C o m m o n w e a l t h Meteorological R e ­ search C e n t e r in M e l b o u r n e . It ex­ t e n d s from t h e surface t o 100 k m and is a c o m b i n e d grid p o i n t and s p e c t r a l m o d e l in w h i c h F o u r i e r m o d e s are used to r e p r e s e n t east-west variations and grid p o i n t s in t h e n o r t h - s o u t h direction. F e w results w e r e presented. The most note­ w o r t h y results d e m o n s t r a t e d t h e m o d e l ' s ability t o simulate t h e J a n u ­ ary z o n a l flow configuration fairly well. A m o d e l being developed at Ox­ ford University was described b y R . S . H a r w o o d and J . A . P y l e (United K i n g d o m ) . It is mainly i n t e n d e d t o study t h e i n t e r a c t i o n of dynamics, p h o t o c h e m i s t r y , and r a d i a t i o n in t h e s t r a t o s p h e r e and m e s o s p h e r e . It is t w o - d i m e n s i o n a l , w i t h e d d y heat t r a n s p o r t s being m o d e l e d after t h e a p p r o a c h of Reed a n d G e r m a n a n d m o m e n t u m t r a n s p o r t s following t h e w o r k of G r e e n . T h e a u t h o r s plan eventually t o i n c o r p o r a t e t h e full p h o t o c h e m i s t r y of o z o n e , including h y d r o g e n and n i t r o g e n reactions. O n e w o n d e r s w h e t h e r t h i s m o d e l is very different from t h o s e currently in o p e r a t i o n in t h e U n i t e d States a n d Canada. I n t h e next presentation, b y J.H.E. Clark ( U n i t e d S t a t e s ) , secondo r d e r effects in a two-layer m o d e l due t o t h e resonant g r o w t h of forced p l a n e t a r y waves for various suitable z o n a l w i n d configurations were con­ sidered. I n spite of t h e strong dissipa­ t i o n in t h e form of N e w t o n i a n cool­ ing and linear drag, significant effects on t h e b a c k g r o u n d z o n a l flow and t e m p e r a t u r e s t r u c t u r e were n o t e d . I t was suggested t h a t t h e timing a n d s u b s e q u e n t evolution of stratospheric warmings might be closely linked t o t h e s t r a t o s p h e r e ' s z o n a l flow being in or very close t o a r e s o n a n t configura­ t i o n . T h i s suggestion is in direct vari­ ance w i t h t h e findings of S i m m o n s , and it might be t h a t t h e two-layer m o d e l is t o o simple t o allow s t u d y of r e s o n a n t effects. E . F . Danielsen ( U n i t e d States), g i v i n g a j o i n t paper w i t h D.G. Deaven, described a two-dimensional

hemispheric m o d e l t o s t u d y trans­ ports from 8 5 0 to 20 m b a r . E d d y m o m e n t u m a n d heat t r a n s p o r t s are calculated from real data b y an o b ­ jective analysis t e c h n i q u e based o n isentropic trajectories a n d t h e conser­ vation of p o t e n t i a l v o r t i c i t y . Double F o u r i e r filtering is used t o r e m o v e all h o r i z o n t a l wavelengths less t h a n 2500 k m from t h e data. T h e m o d e l sounded very promising a n d could prove t o be a valuable t o o l for u p p e r a t m o s p h e r i c research. J . H . E . Clark University of Texas at A u s t i n Austin, Texas 7 8 7 1 2

UAPR C-l 1: Tracer Models B.G. H u n t p r e s e n t e d an inter­ esting if controversial p a p e r i n which a h e m i s p h e r i c general circulation model was used in a n a t t e m p t to simulate t h e vertical s t r u c t u r e of t h e water vapor profile in t h e strato­ sphere. H e used t h e 18-level G F D L model, which e x t e n d s t o 37.5-km altitude, i n c o r p o r a t e d t h e hydrologic cycle, a n d r a n t h e m o d e l for approxi­ mately 2 0 0 d a y s u n d e r a n n u a l mean c o n d i t i o n s . Realistic w a t e r vapor c o n c e n t r a t i o n s were o b t a i n e d in t h e t r o p o s p h e r e . However, in t h e strato­ sphere t h e w a t e r vapor concentra­ tions decreased rapidly w i t h increase of height, being a factor of approxi­ mately 100 lower at t h e t o p of t h e model t h a n at t h e t r o p o p a u s e . H u n t studied t h e c o n t r i b u t i o n s of meridi­ onal circulation a n d t h e eddies to t h e upward t r a n s p o r t of w a t e r vapor and c o n c l u d e d t h a t a l t h o u g h upward t r a n s p o r t was occurring in t h e region of t h e tropical t r o p o p a u s e , t h e water vapor so i n t r o d u c e d i n t o t h e strato­ sphere was being t r a n s p o r t e d back d o w n again b y t h e m e r i d i o n a l circu­ lation at mid-latitudes. Considerable controversy was g e n e r a t e d b y t h e p r e d i c t e d w a t e r vapor distribution and b y t h e q u e s t i o n w h e t h e r such a profile could be t h e s t e a d y state re­ sult of s u c h a m o d e l calculation. The M I T g r o u p ( D . M . C u n n o l d , F . N . Alyea, N . A . Phillips, a n d R.G. Prinn) r e p o r t e d o n a 3-year integra­ tion of a general c i r c u l a t i o n m o d e l in which t h e gross features of t h e dy­

namics a n d t h e o z o n e d i s t r i b u t i o n in the stratosphere a n d t h e seasonal variations were successfully simu­ l a t e d . In particular, the model yielded a p o l a r night j e t of t h e cor­ rect a m p l i t u d e a n d l o c a t i o n t h a t changed over t o easterlies in s u m m e r . The lower stratosphere w a s being forced b y t h e t r o p o s p h e r e , a n d t h e troposphere and upper stratosphere were being forced by t h e in situ dis­ t r i b u t i o n of h e a t i n g a n d cooling. T h e agreement b e t w e e n t h e o b s e r v a t i o n s of a t m o s p h e r i c o z o n e and t h e p r e d i c ­ tions of t h e m o d e l was generally good. I n particular, t h e m o d e l p r o ­ duced p o l e w a r d a n d d o w n w a r d trans­ p o r t of o z o n e , and the p o l e w a r d eddy flux was of similar m a g n i t u d e to t h a t observed at m i d - l a t i t u d e s . Moreover, t h e seasonal v a r i a t i o n of c o l u m n a r (total) ozone at midlatitudes was successfully s i m u l a t e d , as was t h e general level of fluctua­ tions in c o l u m n a r o z o n e . S o m e results of a p h o t o c h e m i c a l diffusive equilibrium c o m p u t a t i o n in a one-dimensional m o d e l for a solar zenith angle of 4 5 ° a n d m a n y chemi­ cal species was p r e s e n t e d , in a j o i n t paper with R . P . T u r c o , b y R . C . Whitten. T h e m o d e l e x t e n d e d from 10 t o 9 0 k m . T h e m o d e l p r o d u c e d an o z o n e profile t h a t was in p o o r agree­ m e n t with observations. T h e profiles of o t h e r chemical species were c o m ­ pared w i t h observations w h e r e possi­ ble. I n a n o t h e r e x p e r i m e n t t h e diur­ nal variations of N O , N 0 , a n d HN0 were e s t i m a t e d . A n e s t i m a t e of t h e effect of N O a n d N O from SST's o n t h e o z o n e d i s t r i b u t i o n was given. T h e m a x i m u m d e p l e t i o n of o z o n e o c c u r r e d at a p p r o x i m a t e l y 30~km a l t i t u d e , p r o b a b l y because there was a m i n i m u m of t h e vertical diffusion coefficient assumed in t h a t region. T h e m o d e l results suggested that t h e r e was a strong c o r r e l a t i o n between ozone depletion and the height of o p e r a t i o n of S S T ' s . T h e m o d e l p r e d i c t i o n s of s o m e of t h e chemical species were q u e s t i o n e d .

t h e n arbitrarily increasing the NO m i x i n g ratio b y 100%. A comparison of t h e results s h o w e d t h e ozone to be r e d u c e d b y 10 t o 20%, with the highest p e r c e n t a g e changes occurring in t h e high-latitude summer. A simi­ lar e x p e r i m e n t was r u n in which the s t r a t o s p h e r i c w a t e r vapor mixing ratio was d o u b l e d arbitrarily. The resulting change in the ozone was only a few p e r c e n t . T h e relevance of this e x p e r i m e n t t o t h e SST, which c o n s t i t u t e s a source of NO* and H 0 t h a t is d e p e n d e n t o n height and lati­ t u d e , was q u e s t i o n e d by the audi­ ence. 2

J . J . Walton r e p o r t e d on some cal­ c u l a t i o n s of t h e local ozone deple­ t i o n d u e t o S S T ' s , using a box model 4 0 0 k m wide b y 3 k m high. The d e p l e t i o n was f o u n d t o be linearly d e p e n d e n t o n t h e N O * injection rate. In a d d i t i o n , t h e sensitivity of the pre­ d i c t e d o z o n e depletion to the dif­ fusion coefficient within the box was discussed. D.M. Cunnold D e p a r t m e n t of Meteorology Massachusetts Institute of T e c h n o l o g y C a m b r i d g e , Massachusetts 02139

UAPRC-12: Tracer Models T h i s session, after several cancella­ t i o n s a n d r e a r r a n g e m e n t s of papers, was still d e v o t e d t o t h e following aspects of SST operations in the l o w e r s t r a t o s p h e r e : (1) a projection of t o t a l S S T e x h a u s t emissions in the year 2 0 0 0 , based o n economic pro­ j e c t i o n s for t h a t period; (2) model e s t i m a t e s of t h e chemistry and dif­ fusion of SST N O * emissions during t h e first h o u r after fly-by; (3) a des­ c r i p t i o n of t h e inner workings of t u r b i n e engines a n d their susceptibil­ ity t o emission r e d u c t i o n s ; (4) a oned i m e n s i o n a l global m o d e l of photo­ c h e m i s t r y i n t h e stratosphere; (5) an R . K . R . V u p p u t u r i p r e s e n t e d s o m e example-of-one of observations sug­ r e d u c t i o n when super­ results of a t w o - d i m e n s i o n a l s t e a d y gesting 0 state m o d e l of t h e s t r a t o s p h e r e t h a t sonic p l a n e s were operating over­ included p r e d i c t i o n s of t e m p e r a t u r e h e a d ; ( 6 ) a m o d e l estimate of as well as chemical c o n s t i t u e n t s . T h e t r o p o spheric t e m p e r a t u r e changes sensitivity of t h e m o d e l t o N O * w a s t h a t m i g h t result from increased par­ evaluated b y first prescribing a lati­ t i c u l a t e b u r d e n s in t h e stratosphere. Since these p a p e r s are to be pub­ t u d e - h e i g h t • d i s t r i b u t i o n of N O * (based o n previous calculations) a n d lished, o n l y t h e following highlights 2

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need be noted here. Professor English projected a fleet of m o r e t h a n 1000 SST aircraft at t h e e n d of t h e n e x t 30 years and a leveling off of these aircraft as t h e HST ( h y p e r s o n i c trans­ port) is phased in. T h e S S T fleet was projected t o inject m o r e t h a n 5 0 0 0 tons of N 0 per d a y . R o u t e distribu­ tions were discussed, b u t n o evalua­ tion of these p r o j e c t i o n s was at­ tempted. G.R. Hilst, C.duP, D o n a l d s o n , a n d R. Contiliano evaluated t h e adjust­ ment of 0 distributions in t h e w a k e of individual SST's due t o t h e N O * emissions by using c o u p l e d , secondorder c h e m i s t r y a n d diffusion models. The main findings were t h a t a near equilibrium b e t w e e n p r o d u c ­ tion and distruction of 0 is quickly established in t h e sunlit s k y , t h e dis­ tribution of 0 in t h e p l u m e is, quite sensitive t o t h e t u r b u l e n t diffusion, and the threshold for s h o r t - t e r m depletion of 0 b y N O * is at least 2 orders of magnitude h i g h e r t h a n was originally p r o p o s e d (again, in t h e sunlit sky.)

Given its frequently speculative nature, it is n o t surprising t h a t t h e discussions during this session were lively. Where t h e y lagged, t h e chair­ m a n , P. G o l d s m i t h , supplied t h e action. G.R. Hilst

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Aeronautical Research Associates of Princeton, I n c . Princeton, New Jersey 0 8 5 4 0

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T. Shimazaki p r e s e n t e d results in a joint paper w i t h T. O g a w a t h a t sug­ gested a slow b u t regular d e p l e t i o n of 0 by c o n t i n u o u s injection of N O * and H^O, ranging u p t o 10—15% of the 0 shield. When t h e source was discontinued, t h e r e c o v e r y of 0 amounts t o their original levels was calculated to t a k e 10—15 years, a period of t i m e c o n s i d e r a b l y longer than estimates of t h e r e s i d e n c e times of materials in t h e o z o n o s p h e r e . 3

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K.H. Grasnick's o b s e r v a t i o n s of 0 profiles during a day w h e n SST traffic was observed o v e r h e a d sug­ gested a c o n c o m m i t a n t decrease of about 1 0 - 1 5 % . T h e validity of these data was still u n d e r s t u d y , and t h e p o s s i b i l i t y o f simply f o r t u i t o u s events cannot be dismissed. 3

S.H. Schneider's calculations of possible t r o p o s p h e r i c t e m p e r a t u r e anomalies due t o changes in aerosol burdens in the s t r a t o s p h e r e appeared to agree well w i t h e s t i m a t e s b y others (a greater effect w i t h decreas­ ing than with increasing b u r d e n s , b u t over a narrow range a r e s p o n s e of i ^ C per 1% change in a l b e d o ) . It was noted in t h e discussion t h a t t h e latitudinal variation of t h i s effect might be m o r e i m p o r t a n t t h a n its magnitude.

UAPRC-13: Tracer and Radiation Models J.W. Kidson (New Zealand Mete­ o r o l o g i c a l S e r v i c e ) opened the UAPRC-13 session by indicating t h a t t h e presentations would serve to p r o ­ vide t h e conference transition from results of tracer models to t h o s e of radiation models. E. Hesstvedt (Insti­ t u t e of Geophysics, University of Oslo) described t h e i m p o r t a n t e x t e n ­ sion of his earlier steady state w o r k t o treat t h e t i m e - d e p e n d e n t situation w i t h annual solar variability. H e care­ fully reviewed t h e assumptions a n d limitations of his m o d e l (e.g., only 10—35 km in t h e vertical, n o diurnal variation, parameterized t r a n s p o r t , 36 reaction set) and emphasized his coordinating studies with a m o r e de­ tailed one-dimensional m o d e l . A f t e r describing t h e generally good results of m o d e l studies o n t r a c e s p e c i e s distributions (e.g., slightly t o o m u c h o z o n e , b u t quite good seasonal a n d latitudinal varia­ t i o n ) , Hesstvedt discussed t h e over­ riding i m p o r t a n c e of simulation of transport in t h e lower stratosphere as compared with m a n y of t h e refine­ m e n t s being m a d e in t h e t r e a t m e n t of chemistry. T h e major discrepancy was for carbon m o n o x i d e , w h i c h did n o t show t h e observed sharp d r o p across t h e t r o p o p a u s e for results still unexplained. T h e second paper, p r e s e n t e d b y M.C. MacCracken and c o a u t h o r e d b y F.M. Luther, reviewed t h e general s t r u c t u r e of their zonal climate model. In comparison w i t h Hesstvedt's model, t h e zonal m o d e l at­ t e m p t s to calculate t h e r a d i a t i o n a n d transport response to a p e r t u r b e d a t m o s p h e r e . T h e inclusion of t h e parameterized atmospheric processes (e.g., convection, clouds, a n d radia­

tion) c o m p a r e s well w i t h GCM's, b u t t h e critical r e p r e s e n t a t i o n of e d d y fluxes is in need of c o n t i n u i n g a t t e n ­ tion and validation. T h e m o d e l is n o w being r u n to d e t e r m i n e its steady state climatic state, which appears t o a p p r o x i m a t e present an­ nual averages, prior t o an extensive sequence of seasonal cycle validation and sensitivity studies. T h e m o d e l should serve t o bridge t h e gap in climate m o d e l s b e t w e e n the very simple ones of Sellers a n d B u d y k o and t h e complex G C M ' s , hopefully offering guidance for further climate studies. T h e emphasis t h e n switched t o radiation transport w i t h H. Grassl ( I n s t i t u t fur Meteorologie, Universitat Mainz) discussing ' A t m o s p h e r i c A b s o r b e r s in t h e W i n d o w Regions and T h e i r Influence o n Radiative Heating and Cooling.' First, he em­ phasized t h e i m p o r t a n c e of e t y p e absorption (dependent b o t h on water vapor mass and water v a p o r pressure) on infrared radiative cooling, especi­ ally in t h e tropics in t h e lower a t m o ­ sphere a n d in i n t e r p r e t a t i o n of satel­ lite d a t a o n surface t e m p e r a t u r e s . This was based on b e t t e r agreement b e t w e e n m o d e l and observation w h e n it was included. A n d second, he p o i n t e d o u t t h e s t r o n g depen­ dence o n relative h u m i d i t y of aerosol a b s o r p t i o n in t h e visible a n d infrared w i n d o w , because t h e size of m a n y aerosols can change as t h e y absorb water. This results, in effect, in t h e optical p r o p e r t i e s of aerosols chang­ ing a n d increases t h e difficulty in judging t h e energy b a l a n c e p e r t u r b a ­ tions t h a t will occur if w e further pollute the atmosphere. S.F. W o r o n k o ( A t m o s p h e r i c En­ v i r o n m e n t Service, T o r o n t o ) n e x t p r o p o s e d a different radiation param­ eterization for infrared heating rates and fluxes for inclusion in general circulation models as a step b e y o n d t h e c h a r t m e t h o d s . A statistical b a n d m o d e l f o r u m l a t i o n is used to inte­ grate over t h e Voigt lines, and t h u s , unlike t h e Curtis m a t r i x m e t h o d , t h e m o d e l can t r e a t variable vertical p r o ­ files of various absorbers, including clouds a n d aerosols. A g r e e m e n t was quite g o o d in the t r o p o s p h e r e , b u t t h e r e were discrepancies above t h e tropopause. T h e final paper, c o a u t h o r e d b y J.B. Pollack (NASA A m e s Research

Center) a n d O.B. T o o n ( L a b o r a t o r y for P l a n e t a r y Studies, Cornell Univer­ sity) and p r e s e n t e d b y Pollack, had t h e descriptive title 'A S t u d y of t h e Effect o f S t r a t o s p h e r i c Aerosols P r o d u c e d b y SST Emissions on t h e A l b e d o a n d Climate of t h e E a r t h . ' By using t h e doubling m e t h o d (given t h e a s s u m p t i o n s of 2 0 spectral b a n d s and 15 vertical levels), a m u l t i p l e scatter­ ing calculation t h a t could include aerosols a n d clouds was carried o u t with t h e a u t h o r s ' o w n laboratoryobserved, spectrally varying, optical p r o p e r t i e s of stratosphericlike aero­ sols in o r d e r t o assess t h e albedo ef­ fect of p o t e n t i a l SST sulfur dioxide e m i s s i o n s . S u p p o s i n g a present stratospheric optical d e p t h of 0.01 at 0.55 }im, a subject of s o m e contro­ versy, t h e y calculated t h e effect of increasing this u p t o 0 . 0 3 , which is a very u p p e r e x t r e m e e s t i m a t e of SST effects, t o be a p l a n e t a r y albedo change from 0 . 3 3 1 2 5 t o 0 . 3 3 3 1 8 . T h e y scaled t h e resulting decrease in available t r o p o s p h e r i c energy t o de­ rive a global average surface tempera­ t u r e change of 0.3°K (I get 0.23 for T = 2 7 8 ) , w h i c h t h e y suggest could be marginally significant. This entire calculation of climate change ignores n o n r a d i a t i o n feedbacks, such as those i n c l u d e d in climate m o d e l s like M a c C r a c k e n ' s , and t h u s should be viewed as o n l y a very c r u d e estimate. Discussion also p o i n t e d o u t t h a t reducing t h e sulfur in t h e fuel b y u p t o a f a c t o r of p e r h a p s 10 was a rela­ tively inexpensive and available solu­ tion t o this p r o b l e m . M.C. MacCracken Lawrence Livermore L a b o r a t o r y University of California Livermore, California 9 4 5 5 0

UAPRC-14: Radiation Models T h e r m a l radiation from t h e poly­ atomic molecules ( H 0 , C 0 , 0 ) in the atmosphere tends to smooth a temperature perturbation and thus dissipates t h e p o t e n t i a l energy avail­ able to g e n e r a t e a t m o s p h e r i c m o t i o n . R.A. Craig reviewed t h e dynamical aspect of radiative dissipation based on t h e characteristic t i m e constant for radiative r e l a x a t i o n of a small t e m p e r a t u r e p e r t u r b a t i o n in t h e 2

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a t m o s p h e r e . F o r idealized a t m o ­ spheres with n o water v a p o r c o n d e n ­ sation and n o p h o t o c h e m i c a l o z o n e reactions, t h e r e l a x a t i o n t i m e con­ stant has b e e n estimated t o b e a b o u t 10 days or longer. Craig p o i n t e d o u t , however, t h a t this n u m e r i c a l value may n o t always be applicable t o t r o p o s p h e r i c d y n a m i c s , since c l o u d s generated by c o n d e n s a t i o n of w a t e r vapor modify t h e r a d i a t i o n field con­ siderably. F e w analyses of t h e radia­ tive effect have b e e n m a d e d u r i n g t h e course of w a t e r vapor c o n d e n s a t i o n , and t h e s t u d y of t h e d y n a m i c s of t h e system of r a d i a t i o n , c o n d e n s a t i o n , and m o t i o n is desired. I n t h e stratosphere t h e m a i n avail­ able p o t e n t i a l energy is g e n e r a t e d b y solar heating d u e t o o z o n e a b s o r p ­ tion. Since t h e p r o d u c t i o n r a t e of o z o n e is related negatively t o t h e local t e m p e r a t u r e , an increase of t e m p e r a t u r e is u l t i m a t e l y c o u p l e d with a decrease of local h e a t i n g of o z o n e absorption ( L i n d z e n - G o o d y effect). In t h e u p p e r s t r a t o s p h e r e above 40 k m this effect e x c e e d s t h e radiative r e l a x a t i o n d u e t o t h e C 0 15-/I band, and the temperature damping is governed exclusively b y p h o t o c h e m i c a l reactions. I n this re­ gard, D . Blake a n d R . S . L i n d z e n gave a p a p e r on t h e u p d a t e d t h e o r y of t h e j o i n t photochemical-radiative d a m p ­ ing of t e m p e r a t u r e p e r t u r b a t i o n s in t h e stratosphere. I n an earlier s t u d y by Lindzen and G o o d y t h e p r o d u c ­ t i o n of o z o n e was calculated b y t h e Chapman reaction scheme, which does n o t involve catalytic r e a c t i o n s of N O * and h y d r o g e n c o m p o u n d s . Blake and L i n d z e n calculated t h e t e m p e r a t u r e d i s t r i b u t i o n t h a t is in equilibrium w i t h t h e r a d i a t i o n field and t h e p h o t o c h e m i s t r y associated w i t h o z o n e u n d e r t h e influence of N O * and h y d r o g e n species. A l s o , it was s h o w n t h a t t h e characteristic re­ laxation t i m e for t e m p e r a t u r e per­ t u r b a t i o n s is r e d u c e d b y a f a c t o r of a b o u t 2 c o m p a r e d w i t h t h e case when only p u r e radiative dissipation b y C 0 is considered. T h e c o m b i n e d radiative and p h o t o c h e m i c a l relaxa­ t i o n m a y dissipate e d d y available p o t e n t i a l energy within 1 . 5 - 2 . 5 d a y s at t h e 50-km level in t h e s t r a t o ­ sphere. Since this t i m e scale is c o m ­ parable t o t h e t i m e scaie n e e d e d for t h e adjustment b y gravitational a n d Coriolis forces, t h e d a m p i n g p l a y s an 2

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i m p o r t a n t role in stratospheric dynamics. T . Sasamori presented a result of n u m e r i c a l c o m p u t a t i o n s of the s t r a t o s p h e r i c circulation simulated b y a simple F o u r i e r model in which o n l y a single planetary wave is con­ sidered t o interact with the zonally averaged m e a n m o t i o n . The individ­ ual effect of forcing and dissipation existing in t h e stratosphere was ana­ lyzed in t e r m s of t h e radiative heat­ ing a n d cooling and the planetary wave originating from the tropo­ s p h e r e . A t t h e solstice the basic s t r a t o s p h e r i c circulation by radiative h e a t sources is a single meridional c i r c u l a t i o n w i t h t h e pole-to-pole m e r i d i o n a l m o t i o n combined with t h e u p w a r d a n d downward motions in t h e s u m m e r and winter hemi­ s p h e r e , respectively. T h e meridional p r e s s u r e g r a d i e n t d r i v i n g the m e r i d i o n a l m o t i o n is in geostrophic b a l a n c e w i t h easterly winds in the s u m m e r h e m i s p h e r e and with west­ erly w i n d s in t h e winter hemisphere. T r o p o s p h e r i c m o t i o n s modify the s t r a t o s p h e r i c m o t i o n s through two w a y s . T h e t r o p o s p h e r i c Hadley cell in t h e t r o p i c s enhances the down­ w a r d m o t i o n in t h e stratosphere at m i d - l a t i t u d e s and intensifies the z o n a l m o t i o n in t h e winter strato­ s p h e r e . Large-scale planetary waves originating in t h e stratosphere gener­ ate a d d i t i o n a l sources of westerly m o m e n t u m and sensible heat in the s t r a t o s p h e r e , a n d induce a secondary m e r i d i o n a l circulation in high lati­ t u d e s of t h e w i n t e r stratosphere. J . F . L o u i s , J. L o n d o n and E.F. Danielsen discussed t h e meridional c i r c u l a t i o n in t h e stratosphere on the basis of t h e o r e t i c a l and observed data u p t o 5 0 k m . T h e diabatic heating r a t e w a s evaluated through calcula­ t i o n s of radiative flux divergence using t h e observed data of tempera­ t u r e a n d t h e distribution of H 0, C 0 , 0 , a n d 0 . Computations of e d d y t r a n s p o r t of sensible heat were based o n t h e t e m p e r a t u r e and wind o b s e r v a t i o n s . T h e mean vertical m o t i o n was t h e n calculated from t h e s e h e a t sources b y using the therm o d y n a m i c a l e q u a t i o n combined w i t h t h e e q u a t i o n of mass contin­ u i t y . A t t h e solstice t h e meridional c i r c u l a t i o n in t h e lower stratosphere is characterized by a weak cell of m e r i d i o n a l wind directed away from 2

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equatorial regions a n d a reverse cir­ culation in t h e higher l a t i t u d e of t h e winter hemisphere. T h e reverse circu­ lation diminishes in i n t e n s i t y w i t h height and only a large s u m m e r - t o winter-hemisphere m e r i d i o n a l circu­ lation dominates in t h e u p p e r s t r a t o ­ sphere.

T h e next speaker, S.P. A r y a , re­ p o r t e d on ' C o n t r i b u t i o n of F o r m Drag o n Pressure Ridges t o t h e Air Stress o n Arctic I c e . ' Since these re­ sults have b e e n published previously, t h e y are n o t discussed here. I n a simi­ lar area of interest R . A . B r o w n , (University of Washington) discussed 'Air Stress Acquisition and Evalua­ T . Sasamori t i o n over the Arctic Ocean.' O n e National Center for m o n t h of meteorological data o n t h e Atmospheric Research ice of t h e A r c t i c Ocean was used t o Boulder, Colorado 8 0 3 0 2 o b t a i n a g o o d p a r a m e t e r i z a t i o n of the air stress. These data were used t o determine t h e plan for data ac­ quisition and evaluation in t h e forth­ coming year-long Aidjex Field S t u d y . MPR-1' Surface Wind Regime and Energy Budget I n t h e second part of t h e session, The first session of t h e 'Meteorol­ which was on 'Energy Budget,' t h r e e ogy of the Polar R e g i o n s Symposi­ papers were also p r e s e n t e d . W.F. um' was entitled 'Surface Wind Re­ B u d d gave an excellent paper o n gime and Energy B u d g e t . ' I n t h e first 'Variations in A n t a r c t i c Sea Ice a n d part, on wind regime, t h r e e talks T e m p e r a t u r e . ' A strong correlation were given. F . L o e w e , a p i o n e e r of was found for Laurie Island b e t w e e n polar meteorology a n d f o u n d e r of variations in t h e mean a n n u a l t e m ­ the meteorological d e p a r t m e n t of t h e p e r a t u r e and t h e d u r a t i o n of t h e sea host university, o p e n e d t h e session ice, such t h a t a change of 1°C in t h e with an excellent talk o n t h e diurnal a n n u a l m e a n t e m p e r a t u r e cor­ wind variation above t h e i n n e r p a r t s responds t o a b o u t 7 0 days' variation of ice sheets ( G r e e n l a n d a n d A n t a r c ­ in t h e d u r a t i o n of t h e sea ice. In tica). F r e q u e n t l y , t h e highest wind general there seems t o be consider­ speed is observed n e a r m i d d a y in able correspondence b e t w e e n those summer, whereas b e c a u s e of t h e regions around t h e A n t a r c t i c w i t h stronger development of t h e cold air t h e coldest t e m p e r a t u r e s a n d those layer near t h e surface d u r i n g t h e of greatest sea ice e x t e n t . These re­ night, a m a x i m u m at t h a t t i m e might sults confirm t h a t large-scale varia­ have been expected a n d is actually tions in sea ice e x t e n t and in surface found near t h e b o r d e r of t h e ice mean t e m p e r a t u r e are related a n d sheet. However, in t h e i n t e r i o r t h e persist over t h e t i m e scale of seasons slope is small; t h e surface wind is o r longer. M e a s u r e m e n t s of heat weak and can be s p e e d e d u p b y a budget over sea ice and ocean water stronger wind in t h e free a t m o s p h e r e t h r o u g h o u t t h e year n e a r Mawson above t h e g r o u n d layer if this u p p e r were used with other d a t a t o esti­ wind has a sufficiently s t r o n g com­ m a t e t h e effect of t h e variations in ponent in the direction of t h e surface sea ice extent o n t h e heat b u d g e t of wind. Owing t o t h e big d i u r n a l varia­ t h e southern h e m i s p h e r e t h r o u g h o u t tion of t e m p e r a t u r e in t h e g r o u n d t h e year and from year t o year. T h e layer, the stability n e a r t h e g r o u n d is n e x t paper, entitled 'A S t u d y of H e a t diminished during t h e m i d d a y h o u r s . Budgets over Sea Ice a n d Water N e a r This leads to a m o r e effective speed­ Mawson, A n t a r c t i c a , ' b y I. Allison, ing up a r o u n d m i d d a y a n d results in was presented b y W . F . B u d d . T h e a wind m a x i m u m at t h a t t i m e of t h e paper discussed a 9 - m o n t h m i c r o day. Several of t h e s t a t i o n s in t h e meteorological s t u d y over an A n t a r c ­ inner parts of ice sheets d o indeed tic annual sea ice cover near Mawson. frequently have an a p p r o p r i a t e rela­ Profile and r a d i a t i o n m e a s u r e m e n t s tion of u p p e r and slope wind. A were m a d e over open water before second explanation of t h e wind t h e ice formed, during t h e f o r m a t i o n maximum near m i d d a y can be de­ and g r o w t h of t h e ice cover, a n d rived from t h e c o m b i n a t i o n of t h e during t h e early part of t h e decay upper geostrophic w i n d and t h e before the eventual b r e a k u p of t h e 'thermal wind' caused b y t h e inclined sea ice. T h e last paper of t h e session cold-air layer near t h e g r o u n d . was 'The C o m b i n e d Heat, Ice, a n d

Water Balance of McCall Glacier, Alaska' b y G. Wendler a n d N . Ishik a w a . T h i s comparison was carried o u t o n a n arctic glacier for a b o u t half t h e a b l a t i o n period w i t h fairly g o o d a g r e e m e n t . T h e detailed results of this stuply will appear s h o r t l y in t h e J o u r n a l of Glaciology. G e r d Wendler Geophysical I n s t i t u t e University of Alaska F a i r b a n k s , Alaska 9 9 7 0 1

MPR-2: Radiation Balance and Atmospheric Circulation T h e second session of t h e Mete­ orology of t h e Polar R e g i o n s was en­ titled ' R a d i a t i o n Balance and A t m o ­ spheric Circulation.' This session was further subdivided i n t o t w o sections (1) R a d i a t i o n , Moisture, a n d O z o n e and (2) Polar T r o p o p a u s e and Circu­ lation. F o u r papers w e r e scheduled to b e p r e s e n t e d u n d e r e a c h subsec­ tion. However, it was u n f o r t u n a t e t h a t n o n e of t h e a u t h o r s of t h e five papers from t h e U S S R were able t o present t h e papers in p e r s o n . F u r ­ t h e r m o r e , one of these papers was w i t h d r a w n and a n o t h e r replaced w i t h o u t prior n o t i c e . T h e papers presented in t h e ses­ sion, a l t h o u g h they can be classified into t h e categories m e n t i o n e d above, dealt w i t h very different aspects of t h e subjects. E a c h p a p e r discussed a specific t o p i c or t e c h n i q u e t h a t h a d very little bearing o n t h e others. T h e first p a p e r , presented b y E. R a s c h k e , used N i m b u s 2 and 3 satellite data t o c o m p u t e t h e t o t a l a l b e d o of t h e e a r t h - a t m o s p h e r e system and p r e ­ sented t h e spatial and t e m p o r a l varia­ tions in a series of m a p s . T h e m o s t i m p o r t a n t result of t h i s p a p e r is t h a t t h e e a r t h - a t m o s p h e r e system is darker and warmer w h e n viewed from space t h a n was originally be­ lieved, t h e albedo being s o m e w h a t less t h a n t h a t given in t h e literature. R a s c h k e ' s p a p e r m a y be o n e of t h e first a t t e m p t s t o d o a c o m p r e h e n ­ s i v e d e t e r m i n a t i o n of t h e e a r t h albedo b y using satellite data. H o w ­ ever, t h e accuracy of his values m a y be q u e s t i o n a b l e in polar regions be­ cause of t h e low sun angle and t h e reliability of t h e satellite sensors a n d

their c a h b r a t i o n . T h e use of satellites t o m e a s u r e earth's a l b e d o is very promising b u t m a y need considerable i m p r o v e m e n t in b o t h t h e technique and t h e satellite t e c h n o l o g y . I n t h e n e x t paper D.C. T h o m p s o n s u m m a r i z e d t h e m e a s u r e m e n t of total clear sky (solar + sky) radiation, t e m p e r a t u r e , a n d cloud cover at Scott base in t h e A n t a r c t i c since 1957. T h e p a p e r was divided i n t o t w o p a r t s . T h e main conclusion of t h e first p a r t was t h a t in t h e s o u t h e r n hemisphere t h e recovery of clear-sky radiation after a volcanic eruption such as Agung is less rapid t h a n was originally believed a n d t h e n e w equi­ librium value is lower t h a n t h e value in t h e p r e e m p t i o n c o n d i t i o n . T h e second p a r t of t h e p a p e r s h o w e d t h a t there was a d o w n w a r d t r e n d in solar radiation a n d an u p w a r d t r e n d in t h e mean t e m p e r a t u r e . Q u e s t i o n arose w h e t h e r t h e s e t r e n d s could be due to the relatively short p e r i o d of time that was considered for analysis. T h e n e x t four papers were n o t presented by t h e a u t h o r s . T w o of t h e m w e r e presented b y E.P. Borisenkov a n d t h e o t h e r t w o by A . A . Girs. I t is t h e writer's opinion t h a t very little i n f o r m a t i o n on t h e c o n t e n t s of t h e papers o t h e r t h a n t h a t available from t h e abstracts was c o m m u n i ­ cated t o t h e p a r t i c i p a n t s of t h e s y m p o s i u m . This was t h e m o r e true because n o discussion was enter­ tained at t h e end of t h e presenta­ tions. T h e final p a p e r of t h e session, pre­ sented b y G. Wendler, dealt w i t h n e w t e c h n i q u e s of using E r t s 1 satellite data t o d e t e r m i n e t h e velocity vector of sea ice m o v e m e n t a n d melting of ice. K.O.L.F. Jayaweera Geophysical I n s t i t u t e University of Alaska F a i r b a n k s , Alaska 9 9 7 0 1

MPR-3: Polex Discussion T h e session was chaired b y Ye. P. Borisenkov. T h e r e were j u s t eight speakers o n subjects p e r t i n e n t t o P o l e x - N o r t h and P o l e x - S o u t h , fol­

lowed by a p o i n t e d discussion p e r i o d t h a t was highlighted b y e x t e m p o r a ­ n e o u s r e m a r k s b y R . S t e w a r t , chair­ m a n of t h e J o i n t Organizing C o m ­ m i t t e e of G a r p . T h e gist of S t e w a r t ' s r e m a r k s was that polar d a t a are less vital t o t h e objectives of G a r p t h a n are t r o p i c a l data, a l t h o u g h P o l e x m a y have its o w n rationale, a n d t h e G a r p J o i n t Organizing C o m m i t t e e c a n n o t j e o p a r ­ dize the credibility of its r e c o m ­ m e n d e d p r o g r a m by espousing p r o ­ grams t h a t are n o t vital t o t h e G a r p objectives. O t h e r speakers p o i n t e d o u t t h a t a Polex-South p r o g r a m is essential for G a r p , particularly for its s e c o n d o b ­ jective, and t h a t it can be c o m p o s e d of c o m p o n e n t s of n a t i o n a l p r o g r a m s already in existence with n o diver­ sion of funds t h a t s u p p o r t G a r p di­ rectly. M.J. R u b i n National Oceanic and A t m o s p h e r i c Administration Rockville, Maryland 2 0 8 5 2

US-2: Upper A tm osphere Meteorology T h e titles of nine p a p e r s sched­ uled for p r e s e n t a t i o n in t h e session on 'Upper Atmosphere Meteorology' confirmed t h a t t h e r e are m a n y w a y s of studying t h e high a t m o s p h e r e . U n f o r t u n a t e l y , t h r e e p a p e r s were w i t h d r a w n and t h r e e o t h e r s w e r e n o t presented, leaving a minisession of three scheduled c o n t r i b u t i o n s a n d one s u p p l e m e n t a r y paper. Y e t w i t h i n this reduced f r a m e w o r k an inter­ esting cross s e c t i o n of w o r k was p r e ­ sented, with t h e guidance of t h e chairman, H . R . Phillpot. M u c h discussion was p r o v o k e d b y t h e opening p a p e r , o n ' S t r a t o s p h e r i c Responses t o Solar P r o t o n E v e n t s ' by C.S. Zerefos ( N a t i o n a l Hellenic R e ­ search F o u n d a t i o n , A t h e n s ) . Zerefos showed statistically significant evi­ dence of 24-hour 100- a n d 5 0 - m b a r height changes a n d of increases in t h e 100- t o 50-mbar layer m e a n t e m p e r a ­ t u r e t h a t o c c u r r e d after i m p o r t a n t solar flares. T h e latter consisted of 33 cases of t h e m o r e energetic p r o ­

t o n e v e n t s in 1 9 5 6 - 1 9 6 9 . The a m o u n t of w a r m i n g observed in the N o r t h A m e r i c a n area (north of 6 5 ° N ) , t h o u g h slight, would require an energy flux m u c h greater than t h a t supplied t o t h e layer by solar p r o t o n s . S u c h warming, according to Z e r e f o s , could b e produced by increased U V a b s o r p t i o n due to only a 1% increase of o z o n e . T h e s e c o n d p a p e r , by G.N. Glazov, V . E . Zuev, G.M. Krekov, AX P o p k o v , a n d V . G . Astafurov, was p r e s e n t e d by Zuev (director of the I n s t i t u t e of A t m o s p h e r i c Optics A c a d e m y of Sciences, USSR, Sibe­ rian B r a n c h , T o m s k ) . It concerned 'Laser S o u n d i n g of Stratosphere and M e s o s p h e r e , ' an activity that has in­ volved s o m e 3 0 g r o u p s of workers. In Z u e v ' s description of several aspects of t h e laser research, great concern was s h o w n for o p t i m u m sounding t e c h n i q u e s and detailed error analy­ sis. A p p l i c a t i o n s include determina­ t i o n of vertical density profiles, the finely stratified structure of aerosol layers a n d u p p e r cloud levels, and op­ tical p r o p e r t i e s of noctilucent clouds. Z u e v i n d i c a t e d t h a t a detailed 30page r e p o r t w o u l d be available on request. T h e t h i r d p a p e r was on 'Rocket M e a s u r e m e n t s of High-Altitude Mo­ lecular O x y g e n ' at 7 0 - 1 4 0 km by t h e j o i n t use of t w o simple ion cham­ bers a n d was presented by the third of t h e t h r e e a u t h o r s , J.H. Carver, B . H . H o r t o n , a n d M. Ilyas (Adelaide U n i v e r s i t y ) . I n addition to 0 con­ c e n t r a t i o n s , t h e technique yields solar m i n i m u m brightness tempera­ t u r e a n d solar fluxes in the band 15 7 0 - 1 6 6 0 A . Oxygen densities f r o m t w o d e t e c t o r s flown on a r o c k e t l a u n c h e d at Woomera on N o v e m b e r 2 3 , 1 9 7 2 , were generally l o w e r t h a n in o t h e r published results and models. T h e additional paper, by E.A. L a u t e r a n d C. E n t z i a n , presented by t h e l a t t e r ( D D R Zentralinstitut fur Solar-Terrestrische Physik), was an­ o t h e r i n t h e long line of intriguing r e c e n t comparisons of ionosphenc w i n t e r anomaly behavior with the n e u t r a l stratospheric behavior. Espe­ cially n o t e w o r t h y was a coherent b e h a v i o r a m o n g ground-based ionos p h e r i c m e a s u r e m e n t s and strato­ spheric t e m p e r a t u r e in the major 2

warming event of J a n u a r y - F e b r u a r y 1973. R . S . Quiroz Upper Air Branch, NMC National Oceanic and A t m o s p h e r i c Administration Hillcrest Heights, M a r y l a n d 2 0 2 3 5

US-3: Atmospheric Aerosols Five papers were p r e s e n t e d in Session US-3. T h e first, b y J.G. Kuriyan, was titled ' A t m o s p h e r i c Particulate Sizes F r o m Polarization Measurements.' T h e a u t h o r applied a UCLA-TRW p o l a r i m e t e r for t h e study of haze particles i n t h e Los Angeles area. Simple t h e o r e t i c a l anal­ ysis shows t h e feasibility of similar techniques, mainly investigating t h e presence of polluting aerosols, assum­ ing that they can be characterized b y the Divergian's size d i s t r i b u t i o n ( F distribution f u n c t i o n ) . T h e results of measurements with t h e i n s t r u m e n t s mounted on t h e g r o u n d a n d o n t h e airplane as well s h o w a surprisingly large number of particles w i t h radii in the range of 0 . 0 5 - 0 . 5 jum. T h e comparison of technical, o p e r a t i o n a l , and economical p a r a m e t e r s show some advantages of t h e a p p l i c a t i o n of polarization t e c h n i q u e c o m p a r e d with multispectral r a d i a t i o n tech­ nique in measuring t h e size of scatterers in planetary a t m o s p h e r e s . The discussion was m a i n l y fo­ cused on the possible n o n u n i q u e n e s s of the applied t h e o r e t i c a l m o d e l for the evaluation of t h e m e a s u r e d data. The second p a p e r , b y E.K. Bigg and A. O n o , was t i t l e d 'Chemical Identification of A t m o s p h e r i c A e r o ­ sols.' The use of simple chemical tests is r e c o m m e n d e d for sampling of aerosol particles in l o w - a l t i t u d e as well as in high-altitude w o r k . Par­ ticles were collected at l o w altitudes by e l e c t r o s t a t i c p r e c i p i t a t i o n o n screens with c o n d u c t i n g surfaces a n d by simple i m p a c t i o n t e c h n i q u e in stratospheric levels. Half of each screen was ' s h a d o w e d ' w i t h inert metal such as gold-palladium alloy e v a p o r a t e d in v a c u u m . T h e re­ mainder of t h e screen w a s covered with a thin film of r e a g e n t (e.g., bar­ ium chloride for d e t e c t i o n of sulfate particles) and after sufficient t i m e of

reaction was also s h a d o w e d w i t h gold-palladium alloy. B o t h parts of t h e screen were e x a m i n e d u n d e r elec­ t r o n microscope. Tests for m a n y simple organic substances were also performed. If w e k n o w t h e magnifi­ c a t i o n factor for individual sub­ stances, we can o b t a i n in this way t h e size distribution of aerosol par­ ticles. T h e third p a p e r , b y W.G. Elford and S.A. Y o u n g o n 'Laser Observa­ tions of Aerosols in t h e T r o p o s p h e r e and S t r a t o s p h e r e , ' gave results of observation of t h e back-scattering from aerosols over Adelaide for t h e years 1 9 6 9 - 1 9 7 3 and p r e s e n t e d t h e following conclusions: T h e increase of the intensity of back-scattered light in 1969 was assigned to t h e vol­ canic eruption of F e r u a n d i e in 1 9 6 8 . A n annual variation in t h e s t r a t o ­ sphere scattering with t h e m a x i m u m in March and S e p t e m b e r was inter­ preted in t e r m s of t r a n s p o r t from an e q u a t o r i a l reservoir. Besides very intense scattering at t h e level of 2 0 k m , there was usually f o u n d a sec­ ondary wide b a n d of m u c h lower in­ tensity b e t w e e n 6 0 and 50 k m . T h e results of a s t u d y of t r o p o s p h e r i c p a r a m e t e r s ( t e m p e r a t u r e stratifica­ t i o n , winds, a n d h u m i d i t y ) in rela­ t i o n t o t h e f o u n d scattering from tropospheric particles were discussed. R. Jaenicke presented a p a p e r on ' N e w Results A b o u t t h e T r o p o ­ s p h e r i c Background Aerosol,' de­ scribing t h e origin and development of background aerosol and concen­ trating on the topics (1) size distri­ b u t i o n and behavior of t h e universal dust c o m p o n e n t in air originating over the Sahara and (2) chemical composition of size distribution of t h e b a c k g r o u n d aerosol below 0.1 pm radius. A n increase in c o n c e n t r a ­ tion of nuclei in t h e size range be­ tween 0.07 pm and 0.15 pm in radius was found over t h e N o r t h Atlantic during most r e c e n t years a m o u n t i n g t o 2 0 0 - 5 0 0 nuclei p e r c m . T h r e e d i s t i n c t g r o u p s of particles w i t h mean lifetimes of T = 1.5, 8, and 2 0 days were f o u n d over t h e A t l a n t i c Ocean. Most of the particles w i t h diameters larger t h a n 0.1 jum were c o m p o s e d o f sulfur c o m p o u n d s (30-60%). 3

A p a p e r b y J. P o d z i m e k and J.C. Carstens titled ' S o m e R e m a r k s o n t h e Stratospheric Nuclei C o u n t s ' ana­

lyzed theoretically t h e t h e r m o d y ­ n a m i c c o n d i t i o n s in t h e G E A i t h e n s nuclei counter and considered w h e t h e r we can assume c o m p l e t e e v a p o r a t i o n of a n u c l e u s of volatile s u b s t a n c e in t h e c o u n t e r . T h e final conclusion was that we c a n n o t antici­ p a t e t h e full e v a p o r a t i o n of sulfuric acid n u c l e i in t h e c o u n t e r . We should be m u c h m o r e c o n c e r n e d a b o u t diffusional losses in t h e c o u n t e r during sampling of stratospheric aerosol par­ ticles. Josef P o d z i m e k G r a d u a t e C e n t e r for G l o u d Physics R e s e a r c h University of Missouri Rolla, Missouri

US-4: Atmospheric Radiation T h e first paper, b y A . Mani, O . C h a c k o , V . D e s i k a n , and V.V. A b h y a n k a r , 'Aircraft M e a s u r e m e n t s of t h e A l b e d o of t h e E a r t h a n d of C l o u d s Over India,' r e p o r t e d results of C a n b e r r a aircraft flights over sev­ eral regions of India using an albedo m e t e r ( 0 . 3 - 0 . 7 jim). Flight altitudes ranged from 150 m t o 14 k m , a n d a s u m m a r y of albedo m e a s u r e m e n t s for m a n y t y p e s of clouds and for land and ocean c o m p a r e d closely w i t h o t h e r recent aircraft measure­ m e n t s b y D r u m m o n d a n d Hickey and b y V o n d e r Haar and C o x . G.I. Kouznetzov's paper, 'Optical P r o p e r t i e s of A t m o s p h e r i c A e r o s o l and T h e i r Significance for t h e S t u d y of T r a c e A t m o s p h e r i c C o n s t i t u e n t s , ' was r e a d b y V . E . Zuev. B o t h calcula­ t i o n s a n d a wide variety of experi­ m e n t a l d a t a were p r e s e n t e d for t h e region 0 . 1 - 0 . 9 m in t e r m s of t h e A n g s t r o m a coefficient. I t was re­ p o r t e d t h a t aircraft data s h o w e d a t o decrease w i t h height and t o vary b y a f a c t o r of 2 or 3 above n o r m a l w h e n Sahara dust was p r e s e n t , a n d t h a t t h e optical d e p t h of t h e a t m o s p h e r e was generally greater in t h e m o r n i n g over land and greater in t h e a f t e r n o o n over o c e a n . T . Takashima, in 'Effect of A e r o ­ sol Size Distribution o n Scattered R a d i a t i o n in an I n h o m o g e n e o u s O z o n e A t m o s p h e r e Calculated b y Using t h e " A d d i n g " M e t h o d , ' ad­ dressed t h e p r o b l e m of interpreting

backscattered near-ultraviolet radia­ tion ( 0 . 3 - 0 . 4 fim) as m e a s u r e d from a satellite. He r e p o r t e d t h a t t h e ef­ fect of a doubling of aerosols had small (5%) effect on t h e intensity of radiation; h e also h a d preliminary results on aerosol effects o n t h e de­ gree of polarization t h a t were n o t definitive. A. C o h e n presented a very lucid s u m m a r y of 'Multiple Scattering Measurements as a F u n c t i o n of Wave­ length b y Use of a Dye-Laser' t h a t drew good discussion. His experi­ mental w o r k was directed t o w a r d the question of determining t h e optical d e p t h at w h i c h m u l t i p l e scattering appreciably affects t h e i n t e r p r e t a t i o n of l i d a r m e a s u r e m e n t s . First he d e m o n s t r a t e d t h a t his apparatus could r e p r o d u c e t h e Mie intensity p a t t e r n b y ranging over a AX = 4 0 0 A spectral region with r h e l d c o n s t a n t (Note: a = 2nr/X). T h e n h e increased N, t h e n u m b e r density of spherical particles of c o n s t a n t r, so t h a t optical depth ranged b e t w e e n 0.1 and 3.8. As a result of multiple scattering, t h e intensity p a t t e r n began t o change between optical d e p t h s of 0.2 and 0.3. It was n o t e d in t h e discussion that e x p e r i m e n t a l c o n d i t i o n s could modify t h e s e results, b u t t h e experi­ m e n t was very well received overall: A p a p e r b y A.G. Gorelik, R.B. Bielitch, S.F. Kalachinsky, a n d A.S. N o v o k r e s t c h e n o v a , ' M e a s u r e m e n t s of the A t m o s p h e r i c R a d i a n c e in the 8 - 1 2 M i c r o n Band,' was read by V.E. Z u e v . T h e r e p o r t covered down­ ward r a d i a t i o n in these wavelengths for different angles and different moisture and cloud c o n d i t i o n s . Re­ sults s h o w e d b e t t e r a g r e e m e n t with calculations t h a n might be e x p e c t e d owing t o t h e c o n t i n u u m effect (aero­ sol plus w a t e r v a p o r ) . T h e authors discussed their p r o b l e m a n d made some c o n c u r r e n t infrared a n d micro­ wave m e a s u r e m e n t s . T o m V o n d e r Haar D e p a r t m e n t of A t m o s p h e r i c Sciences Colorado S t a t e University F o r t Collins, C o l o r a d o 8 0 3 0 2

US-5: Boundary Layer Meteorology R.A. A n t o n i a described experi­

m e n t a l d a t a based o n l a b o r a t o r y m e a s u r e m e n t s o n t h e axis of sym­ m e t r y of a h e a t e d t u r b u l e n t j e t , which provided a n i n d i c a t i o n of t h e m a g n i t u d e of t h e c o r r e l a t i o n b e ­ t w e e n Xr * €r> * local rates of dissipation of t h e t e m p e r a t u r e and v e l o c i t y f l u c t u a t i o n s , respectively. He p o i n t e d o u t t h a t he f o u n d n o evi­ dence of any previous e x p e r i m e n t a l results in this area. He also s t a t e d t h a t t h e flatness factor of t h e t e m ­ p e r a t u r e derivative, as m e a s u r e d b y G i b s o n , Stegan, a n d Williams in 1 9 7 0 for t h e a t m o s p h e r i c b o u n d a r y layer over t h e o c e a n could be fairly re­ liably p r e d i c t e d from an analysis based o n a c o n s i d e r a t i o n of t h e s t r u c ­ t u r e functions of t e m p e r a t u r e fluctu­ ations for scales in t h e viscous range. M.R. T h o m s o n discussed s o m e of t h e statistical p r o p e r t i e s of t h e w i n d speed o n t h e basis of a n e m o m e t e r measurements taken approximately 4 m above t h e average r o o f t o p level in an industrial e n v i r o n m e n t . C o n t i n ­ u o u s data were o b t a i n e d for a w h o l e year, and energy-density spectra w e r e calculated. He described t h e s h a p e of t h e spectra above frequencies of 2 c/h as a f u n c t i o n of t i m e a n d t h e 30-min m e a n w i n d speed. V a r i a t i o n of t h e wind speed p r o b a b i l i t y distri­ b u t i o n as a f u n c t i o n of t i m e , as well as t h e p r o b a b i l i t y d i s t r i b u t i o n of gusts above a n d b e l o w t h e 30-min m e a n wind speed, were also dis­ cussed. a n c

n e

S. C h a n d r a described his diffusion data o b t a i n e d b y allowing h e l i u m puffs t o diffuse i n t o an air s t r e a m within a n e u t r a l b o u n d a r y layer. H e analyzed his e x p e r i m e n t a l d a t a in t e r m s of t h e Hay-Pasquill scale p a r a m e t e r |3, w h i c h is t h e r a t i o of t h e L a g r a n g i a n t o t h e Eulerian t i m e scales. Chandra described t h e j3 values o b t a i n e d by Hay and Pasquill ( 1 9 5 9 ) , Mickelsen ( 1 9 5 5 ) , Baldwin a n d Mickelsen ( 1 9 6 2 ) , a n d H a u g e n ( 1 9 6 6 ) a n d concluded t h a t m e a n d e r i n g h a d a sig­ nificant effect o n j3 values. W. G e r s t m a n n discussed experi­ m e n t a l m e a s u r e m e n t s o n t h e fine structure of t h e t h r e e w i n d c o m p o ­ nents a n d of t h e t e m p e r a t u r e at t h e M e t e o r o l o g i c a l Main O b s e r v a t o r y , P o t s d a m , East G e r m a n y . He calcula­ ted t h e t u r b u l e n t h e a t flux, t h e c o m ­ p o n e n t s of t h e friction t e n s o r , a n d t h e spectral variance of t h e vertical

w i n d c o m p o n e n t . T h e quality of the regression r e l a t i o n s and the associ­ a t e d c o n f i d e n c e intervals, calculated for e a c h of t h e parameters, was f o u n d t o b e remarkable in spite of t h e n o n h o m o g e n e i t y of the terrain. A . Mani et al. described the reg­ ular m e a s u r e m e n t s of the dust and nuclei c o n t e n t of the air near the g r o u n d t h a t w e r e made at various s t a t i o n s in I n d i a t o study the charac­ teristic e l e m e n t s of natural pollution near t h e g r o u n d , its origin and vari­ a t i o n w i t h t i m e , seasons, and alti­ t u d e . T h e y p o i n t e d out that the dust c o n t e n t a n d t h e electric field showed seasonal a n d diurnal variations oppo­ site t o t h o s e of t h e small-ion density a n d electrical conductivity. The dust c o n t e n t was f o u n d to be maximum i n t h e h o t p r e m o n s o o n months, w h e r e a s t h e electric field was max­ i m u m in t h e m o n s o o n months. Tur­ b i d i t y coefficient B also showed striking seasonal variations at Poona a n d Delhi, w i t h m a x i m u m values in t h e h o t p r e m o n s o o n months and m i n i m u m in winter. V . E . Z u e v et al. described the ap­ p l i c a t i o n of lasers for control of in­ dustrial p o l l u t i o n a n d indicated that of all t h e remote-sensing methods, lasers were t h e m o s t promising, pri­ marily because of their high sensitiv­ i t y . T h e y described the use of lasers in t h e m e a s u r e m e n t of industrial aer­ osols in t h e U k r a i n e , Soviet Union, a n d stressed t h e care necessary in cal­ i b r a t i o n for t h e accurate response of t h e lasers. M e a s u r e m e n t s on the con­ c e n t r a t i o n s of particles and the c h e m i c a l s t r u c t u r e of particles were outlined. S. Chandra N o r t h Carolina Agricultural a n d T e c h n i c a l S t a t e University G r e e n s b o r o , N o r t h Carolina 27411

PO-1: Large-Scale Wind-Driven Circulation A m i x t u r e of oceanographic top­ ics was covered in Session PO-1. Five p a p e r s were devoted to discussions of o c e a n o g r a p h i c d a t a , t w o papers were c o n c e r n e d w i t h t h e wind stress field o v e r o c e a n s , a n d one described n u m e r i c a l m o d e l i n g of ocean cur­ rents.

As befits a c o n f e r e n c e in Aus­ tralia, the papers o n o c e a n o g r a p h i c observations were all c o n c e r n e d with the Pacific or I n d i a n O c e a n s . I n t h e middle latitudes of t h e N o r t h Pacific, W. White (Scripps O c e a n o g r a p h i c In­ stitution) r e p o r t e d large variations in meridional g e o s t r o p h i c t r a n s p o r t . Variations of u p t o 3 0 % w e r e f o u n d in a data set e x t e n d i n g o v e r 2 0 years. An attempt was m a d e t o f i n d correla­ tion of these variations w i t h wind, but Sverdrup t r a n s p o r t s calculated from actual wind fields s h o w e d n o simple relation t o t h e g e o s t r o p h i c transports. Recent tracking of S w a l l o w floats and observations of surface salinities in the equatorial c u r r e n t s were re­ ported by o c e a n o g r a p h e r s from t h e Centre Ostrom de N o u m e a in New Caledonia. In t h e I n d i a n O c e a n off western Australia a w a v y s t r u c t u r e with a wavelength of 2 0 0 k m was in­ terpreted as R o s s b y waves b y a group from Flinders University of S o u t h Australia. O t h e r o b s e r v a t i o n s in Aus­ tralian waters were given b y R. Radok, w h o is c o n d u c t i n g a currentmeter program in t h e i n s h o r e waters surrounding t h e c o n t i n e n t . John Bye (Flinders University) presented a n e w global analysis of the surface w i n d stress field for t h e author, William E y r e . A n i m p o r t a n t feature of this analysis is t h e inclu­ sion of t h e effect of varying air-sea temperature differences. T h e wind stress field was used as a forcing function for some simple ocean cir­ culation models. The Arctic Ice D y n a m i c s J o i n t Experiment (Aidjex) is an air-sea in­ teraction program t o b e carried o u t in t h e A r c t i c O c e a n during 1 9 7 5 - 1 9 7 6 . Studies of t h e a t m o ­ spheric b o u n d a r y layer in c o n n e c t i o n with this project w e r e given b y Robert Brown. V a r i o u s candidates for modeling t h e p l a n e t a r y b o u n d a r y layer over pack ice w e r e discussed. The most acceptable is a similarity model that agrees w i t h e x p e r i m e n t a l data over a wide r a n g e of roughness and stratification. David Paskousky (University of Connecticut) p r e s e n t e d a numerical, wind-driven m o d e l for circulation in the Gulf of Mexico. A b a r o t r o p i c model with a velocity varying in depth was used t o p r o v i d e some properties of a baroclinic m o d e l b u t

with simplicity. Various features of t h e L o o p C u r r e n t were discussed in relation t o t h e m o d e l . K e n n e t h L. H u n k i n s L a m o n t - D o h e r t y Geological Observatory Palisades, N e w Y o r k 1 0 9 6 4

PO-4: Tides, Fronts, and Acoustics (Part of Session) Of Sessions PO-4 a n d PO-5, I at­ t e n d e d only t h e talk b y S.H. Sharaf El Din o n sea level at Alexandria and Port Said in P O - 4 . Sea level records at Alexandria and Port Said from 1956 t o 1966 were analyzed. T h e y were f o u n d t o correlate well w i t h each other and with sea levels at Haifa and A s h d o d reported previously b y Streim and Rosenau {International Hydrographic Review, 1972). Streim a n d R o s e n a u found t h a t t h e sea level at Haifa and A s h d o d can be correlated with t h e atmospheric pressure difference be­ t w e e n the central and eastern Medi­ terranean. Sharaf El Din f o u n d t h a t t h e sea level at Alexandria a n d P o r t Said also correlates with t h e pressure difference b e t w e e n t h e central and eastern Mediterranean. T h e Nile floods did n o t have a sig­ nificant influence on sea level at either Alexandria or P o r t Said. After t h e Aswan high dam was c o m p l e t e d in 1964, t h e r e was n o change in t h e seasonal variations of sea level. T h e sea level changes do n o t seem t o in­ fluence t h e flow of t h e Nile, al­ t h o u g h salt w a t e r intrudes into s o m e low-lying lakes in t h e delta during periods of s t r o n g onshore winds. Harold S o l o m o n D e p a r t m e n t of E n v i r o n m e n t a l Science Tel Aviv University Tel Aviv, Israel

PO-6: Water Structure C.B. F a n d r y r e p o r t e d o n a data analysis s c h e m e that was developed b y F a n d r y and F.P. B r e t h e r t o n for Mode b u t t h a t has m o r e general ap­ plicability. T h e m e t h o d uses statisti­

cal t e c h n i q u e s t o p l o t fields ( s u c h as velocity or t e m p e r a t u r e ) based o n m e a s u r e m e n t s at a finite n u m b e r of p o i n t s in such a w a y t h a t error is m i n i m i z e d . It t u r n s o u t t h a t an array t h a t is regular in s o m e sense will generally give b e t t e r results t h a n an irregular array. This t e c h n i q u e per­ mits arrays to be t e s t e d a n d an o p t i ­ m u m configuration t o be p r e d i c t e d before field d e p l o y m e n t . T h e possi­ bility of fronts or o t h e r d i s c o n t i n u i t y surfaces c a n n o t be h a n d l e d b y this method. G . L . Mellor r e p o r t e d o n a m o d e l of t h e surface mixed layer of t h e ocean developed b y Mellor a n d P.A. D u r b i n at P r i n c e t o n . T h i s is o n e of several recent models t h a t go b e y o n d t h e classical t r e a t m e n t s , w h i c h con­ sidered only integral p r o p e r t i e s of t h e m i x e d layer, a n d a t t e m p t t o con­ struct a unified t h e o r y of t h e veloc­ ity b o u n d a r y layer (of w h i c h t h e E k m a n layer is t h e simplest example) a n d t h e m i x e d t e m p e r a t u r e layer. A n o t h e r s u c h m o d e l was r e p o r t e d o n b y R. T h o m p s o n in o n e of t h e air-sea i n t e r a c t i o n sessions. Salinity varia­ t i o n s were essentially n o t considered. It was artificially a s s u m e d t h a t salin­ ity is p r o p o r t i o n a l t o t e m p e r a t u r e in t h e m i x e d layer; it w o u l d have b e e n m o r e straightforward t o simply ne­ glect salinity variations at this stage. Empirical turbulence parameter­ i z a t i o n of t h e r e l a t i o n s b e t w e e n fluxes (of heat a n d m o m e n t u m ) a n d gradients (of t e m p e r a t u r e and veloc­ i t y ) , b a s e d o n various e x p e r i m e n t a l results in t h e literature, are an im­ p o r t a n t feature of these r e c e n t mixed-layer theories. I n this c o n n e c ­ t i o n , a major controversy arose over the value of t h e R i c h a r d s o n n u m b e r b e l o w which t u r b u l e n c e develops in t h e surface layer. Mellor a n d D u r b i n argued for a value in t h e range 0 . 2 1 - 0 . 2 5 a n d T h o m p s o n argued for a value of 1, claiming t h a t t h e l o w e r value applies only t o t h e m a i n t e ­ n a n c e of t u r b u l e n c e o n c e it was de­ veloped. T h e n e x t t w o p a p e r s dealt w i t h oceanic micro s t r u c t u r e , t h e only t w o p a p e r s o n this subject at t h e assem­ blies. B o t h dealt w i t h m i c r o s t r u c t u r e in w e s t e r n b o u n d a r y currents a n d represent t h e first a t t e m p t s t o s t u d y m i c r o s t r u c t u r e in sections across b o u n d a r y currents a n d t h e first ex­ cept for one ( m e a s u r e m e n t s in t h e

Florida c u r r e n t referred t o briefly in a paper b y Osborn and C o x ) t o o b ­ s e r v e m i c r o s t r u c t u r e at all in a b o u n d a r y current. J . A . E l l i o t t and N . S . Oakey (Bedford I n s t i t u t e ) r e p o r t e d o n mea­ surements of t h e r m a l m i c r o s t r u c t u r e in a section across t h e gulf stream at 63°W ( s o u t h of Nova Scotia). This project observed very fine scale mi­ c r o s t r u c t u r e w i t h i n s t r u m e n t s having a r e s o l u t i o n of 5 cm. T h e section across t h e stream served mainly t o give a variety of oceanic conditions within a relatively short distance. A significant increase in t h e a m o u n t of m i c r o s t r u c t u r e was f o u n d following t h e passage of a s t o r m . A n array was used t o s t u d y t h e h o r i z o n t a l coher­ ence of features at a distance of t h e order of 5 0 c m . C o h e r e n c e was ob­ served, b u t n o t always in a perfectly horizontal direction. F e a t u r e s were sometimes t r a c e d t o slope u p to 36° from t h e horizontal. Since this is m u c h m o r e t h a n t h e p e r m a n e n t slope of t h e i s o t h e r m s , Elliott tentatively p r o p o s e d t h a t very s h o r t internal waves m a y be present, b u t this sub­ ject requires further s t u d y . H. S o l o m o n r e p o r t e d o n observa­ tions of larger m i c r o s t r u c t u r e of a t y p e originally described b y S t o m m e l and F e d e r o v ( 1 9 6 7 ) in a section across t h e Kuroshio off of J a p a n . T h e t h i n isothermal layers, which have b e e n f o u n d to e x t e n d horizon­ tally u p t o several k i l o m e t e r s in t h e open o c e a n , were observed t o slope roughly parallel to t h e isotherms across t h e K u r o s h i o . E v i d e n c e was also p r e s e n t e d t h a t t h e observed fine saHnity s t r u c t u r e , which in t h e past has b e e n p r e s e n t e d as evidence t h a t t h e m i c r o s t r u c t u r e c a n n o t be formed b y vertical mixing alone (Pingree, 1971), m a y in fact be of i n s t r u m e n ­ tal origin, even o n scales t o o large t o c o r r e s p o n d t o t h e u s u a l timec o n s t a n t spiking. The last t w o papers w e r e r o u t i n e local c o n t r i b u t i o n s . G . R . Cresswell described b u o y observations of t h e East Australian c u r r e n t . Most of t h e talk dealt w i t h technical details of t h e b u o y s and their d e p l o y m e n t . T w o b u o y s have b e e n d e p l o y e d t o date. B.V. H a m o n reviewed a con­ siderable a m o u n t of data f r o m waters off of e a s t e r n Australia t o d e t e r m i n e t h e d o m i n a n t scales of variation of oceanic variables and c u r r e n t s . T h e

scales were d e t e r m i n e d m a i n l y b y visual i n s p e c t i o n , a l t h o u g h spectral analysis was occasionally e m p l o y e d , particularly w i t h sea level r e c o r d s . A spectral analysis of 3 0 years of sea surface t e m p e r a t u r e data at a s t a t i o n off of Cronulla, N e w S o u t h Wales, showed peaks a t 4 m o n t h s a n d 8 m o n t h s . Eddies seem t o be t y p i c a l l y a b o u t 2 5 0 k m in d i a m e t e r a n d t o move a b o u t 3 c m / s . T h e sea surface temperature pattern contains many fronts, which seem t o m o v e r a p i d l y . Harold Solomon D e p a r t m e n t of E n v i r o n m e n t a l Science Tel Aviv University Tel Aviv, Israel

O W-I-l: Wave Dy namics and Prediction T h e t o p i c of p r e s e n t a t i o n s a n d discussion for t h e first p a r t of t h i s session centered a b o u t capillary a n d small waves. O.M. Phillips p r e s e n t e d recent work in c o l l a b o r a t i o n w i t h M X . Banner o n flow visualization studies t h a t display t h e s t a g n a t i o n points and incipient b r e a k i n g p h e ­ n o m e n a of small b r e a k i n g waves. Wave breaking occurs less t h a n w h i t e capping in t h e o p e n ocean. B r e a k i n g is defined as t h e c o n d i t i o n w h e n fluid elements m o v e faster t h a n t h e wave profile. Phillips said t h a t t h e drift layer has a s t r o n g effect o n in­ cipient breaking. A n ever-increasing a m o u n t of research is being d o n e o n small-scale waves, a n d this p a p e r is a very g o o d e x a m p l e of t h e w o r k in progress. G.L. Lleonart followed w i t h a paper ( c o a u t h o r e d b y D . R . Blackm a n ) and film representing wave t a n k m e a s u r e m e n t s of capillary waves. T h e slope was easily discern­ ible with his fine p h o t o g r a p h y of capillary waves. I t was suggested b y Phillips t h a t t h e w i n d stress s h o u l d have b e e n i n c l u d e d in L l e o n a r t ' s analysis. A paper b y M.S. Longuet-Higgins a n d J . S . T u r n e r , presented by T u r n e r , also c o n c e r n e d capillary wave s t r u c t u r e . T h e i r w o r k illus­ t r a t e d t h a t a spilling b r e a k e r c o u l d b e regarded as a t u r b u l e n t gravity cur­ rent of falling t u r b u l e n t foam as it

cascades d o w n t h e face of the wave T u r n e r e q u a t e d t h e entrainment vel o c i t y t o t h e R i c h a r d s o n number that describes t w o opposing effects. One effect p r o d u c e s accelerating flow and t h e o t h e r b u o y a n c y fluxes. There m u s t b e a significant slope to have a d o w n w a r d m o t i o n of the whitecap, a n d t h e p l u m e accelerates smoothly d o w n t h e slope w i t h a velocity that is small c o m p a r e d w i t h t h e upflow. This p h e n o m e n o n occurs with a defi­ nite density difference between the water and the whitecap. A n excellent paper by H. Mits u y a s u , F . Tasai, T. Suhara, S. M i z u n o , M. O h k u s u , T. Honda, and K. Rikiishi described t h e directional f r e q u e n c y spread observed in open o c e a n cloverleaf b u o y data and wind wave t a n k data. A large angular spread was observed in low and high frequencies, whereas t h e directional d e p e n d e n c e at t h e dominant peak was n a r r o w . A similarity to the Pierson-Moskowitz s p e c t r u m for large f e t c h e s was observed. Hasselman c o m m e n t e d o n t h e fine results of Mitsuyasu. Y . T o b a discussed the treatment of w a v e g r o w t h on a macroscopic s c a l e . U s i n g nondimensionalized p a r a m e t e r s h e observed overshoot a n d u n d e r s h o o t p h e n o m e n a . Exper­ i m e n t a t i o n shows t h a t the rate of w o r k d o n e b y wind stress is deter­ m i n e d b y t h e dimensionless U**. T h e final p a p e r in t h e session sup­ plied a g o o d i n t r o d u c t i o n for the af­ t e r n o o n session o n r e m o t e sensing. J . W . W r i g h t explained the basic t h e o r y a n d applications of radar in r e m o t e sensing of t h e ocean. J o h n Hayes I n s t i t u t e of O c e a n o g r a p h y City University of N e w York Bronx, N e w York 10453

OW-I-2: Remote Sensing of Sea State R e m o t e sensing at satellite alti­ t u d e s offers t h e opportunity for global coverage of sea state parame­ ters. T h e papers in this session illus­ t r a t e d t h e variety of applications re­ m o t e sensing techniques offer the field of physical oceanography. The r e p o r t s p r e s e n t e d a well-rounded

look at what is being a c c o m p l i s h e d in remote sensing a n d w h a t we can expect in t h e near f u t u r e . D.E. Barrick e x p l a i n e d various radar techniques, especially highfrequency land-based r a d a r . By D o p pler shifting t h e r a d a r r e t u r n , sea state conditions can be inferred. This technique is limited b y i t s range of apphcabihty. J. Hayes p r e s e n t e d a p a p e r on re­ cent applications of a microwave radar-radiometer a b o a r d Skylab in obtaining wind speeds a n d pressures in the planetary b o u n d a r y layer. A wide range of m e t e o r o l o g i c a l condi­ tions offering different w i n d speeds and directions were o b t a i n e d in t h e first two m a n n e d p e r i o d s of S k y l a b , including t h o s e observed in a pass over hurricane Ava in J u n e 1 9 7 3 . With a n o p e r a t i o n a l i n s t r u m e n t similar t o t h e o n e a b o a r d S k y l a b , wind speeds, directions, a n d pres­ sures could be o b t a i n e d t w i c e daily on a global scale. B.S. Yap lee ( c o a u t h o r A . Shapiro) d e s c r i b e d h o w significant wave heights can be d e t e r m i n e d by m e a n s of a radar altimeter. Aircraft exper­ iments over t h e A t l a n t i c O c e a n were flown to o b t a i n sea s t a t e . It was pointed o u t t h a t t h e geoid can be o b ­ tained t h r o u g h t h e use of such an instrument aboard a satellite. A suc­ cessful a t t e m p t t o define t h e geoid over the P u e r t o R i c a n t r e n c h was accomplished during t h e S k y l a b mis­ sion. The results c o m p a r e very well with shipboard gravimeter studies. J.P. Hollinger e x p l a i n e d t h e pas­ sive radiometer system u s e d o n satel­ lites. By sensing t h e sea surface in t h e presence of f o a m , b r e a k i n g waves, and general sea slope, t h e w i n d speed can be inferred. This t e c h n i q u e is useful until cloud cover b e c o m e s a limiting factor. Satellite o c e a n o g r a p h y and t h e field of r e m o t e sensing is t h e answer to the question of h o w t o o b t a i n global near-synoptic coverage of sea state parameters. T h e p a p e r s p r e ­ sented at this conference gave a g o o d example of t h e various goals being accomplished in this field. T h e b e n ­ efits of r e m o t e sensing w e r e shown to be n u m e r o u s . L o n g - r a n g e w e a t h e r forecasting, where a s p a r e e data base exists, can benefit from t h e global wind speed m e a s u r e m e n t s . T h e ques­

tions and c o m m e n t s in t h i s session were optimistic for future results. J o h n Hayes Institute of Oceanography City University of New Y o r k B r o n x , New Y o r k 10453

OW-II: Internal Waves (Two Sessions) By rough e s t i m a t e , s o m e 25 pa­ pers in t h e overall IAPSO meeting ( a b o u t 120 p a p e r s in a d d i t i o n t o some joint IAMAP air-sea interac­ tions sessions) m e n t i o n e d internal waves in s o m e significant w a y ; a b o u t 14 of this group were specifically o n t h e subject of internal waves. Perhaps only m i c r o s t r u c t u r e received as m u c h m e n t i o n , indicating t h e e x t e n t of t h e popularity of b o t h subjects. However, t h e c o n t e x t in w h i c h in­ ternal waves were s o m e t i m e s dis­ cussed was r a t h e r disturbing t o m e : during t h e OW-II Internal Waves ses­ s i o n , f o r e x a m p l e , o n e speaker seemed t o be trying t o insist t h a t in­ ternal waves in fact exist, a h y p o t h ­ esis that hardly seems to n e e d proof. A n o t h e r questioner during an OW-I session asked if a particular acoustic study had b e e n made sufficiently far offshore ' t o n o t be b o t h e r e d b y in­ ternal tides'; o n e might ask h o w far offshore t h a t is, since internal tides have been measured at t h e b o t t o m and center of t h e major oceans. And t h e r e were c o n t r a d i c t i o n s sometimes h e a l t h y , usually confus­ ing. F o r e x a m p l e , Mysak showed analytically h o w internal waves m a y be scattered, sometimes c o m p l e t e l y , b y m i c r o s t r u c t u r e (one w o n d e r s h o w m u c h of t h e n e x t IAPSO meeting will b e d o m i n a t e d by t h e s e c o m b i n e d subjects), b u t nearly all t h e o t h e r theoretical presentations used a con­ stant or at least a s m o o t h Vaisala profile. In fact, m y overall assessment of t h e view p r e s e n t e d o n internal waves at this IAPSO meeting is t h a t al­ t h o u g h various theoretical investiga­ tions were offered, n o t all of t h e m new, few were really aimed at signifi­ cant questions, and few field data were shown to provide a balanced picture o r an incentive t o t h e t h e o r e ­ tician. There m a y be a h i d d e n factor

h e r e : t h e April 1 9 7 4 A G U m e e t i n g p r o m i s e d an internal wave session t h a t could be a g o o d bit m o r e excit­ ing t h a n t h e IAPSO m e e t i n g . T h i s was in p a r t due t o t h e inability of many prominent workers to attend a m e e t i n g in Australia a n d in part t o t h e c u r i o u s coincidence that a n u m b e r of new a n d significant t h e ­ ories and e x p e r i m e n t a l results w e r e n o t q u i t e r e a d y for J a n u a r y 1974 b u t were e x p e c t e d t o be b r o u g h t t o ­ gether in April. Nevertheless, s o m e striking p r e ­ sentations were m a d e at t h e I A P S O session, a n d t h e i n t e n s i t y of t e a t i m e a n d p u b - t i m e discussions subse­ q u e n t l y confirmed t h e i r value, o r at l e a s t t h e i r c a t a l y t i c potential. Thorpe's work with bores (no p u n ) in L o c h Ness should be a satisfaction to t h e o r e t i c i a n s p u s h i n g finite ampli­ t u d e effects, a v i n d i c a t i o n t o l a b o ­ r a t o r y workers wishing t o r u n c o n ­ t r o l l e d e x p e r i m e n t s in a realistic e n v i r o n m e n t , and a goad t o t h e sea­ going c o m m u n i t y w i t h their c o m ­ placency w i t h relatively c r u d e experi­ m e n t s a n d their submission to t h e m y s t i q u e fostering belief t h a t almost any deep sea m e a s u r e m e n t is w o n d e r ­ ful. A m i d t h e sporadic dullness of cer­ tain p r e s e n t a t i o n s , t h e few available sparks of h u m o r were m u c h a p p r e ­ ciated: e.g., M.E. M c l n t y r e ' s sniping at p e o p l e who d o n ' t answer letters, C. G a r r e t t ' s r e m a r k (read b y G . T . Needier) t h a t t h e G a r r e t t and M u n k s p e c t r u m will h e n c e f o r t h be referred to as GM 7 2 , t h u s suggesting its p l a n n e d obsolescence, and A.D. M c E w a n ' s lovely little Meccano p e n ­ d u l u m driven b y a t i n y m o t o r at twice its natural f r e q u e n c y as a de­ m o n s t r a t i o n of p a r a m e t r i c insta­ bility. T h e p e n d u l u m was sufficiently u n s t a b l e t o n o t even w o r k on t h e first few tries. T h e a b s t r a c t s for OW-II ade­ q u a t e l y describe t h e essence of t h e p a p e r s , b u t n o t t h e a t m o s p h e r e in w h i c h t h e y were given nor t h e r e a c ­ t i o n t o t h e m . Suffice it t o say t h a t t h e a u d i e n c e seemed prepared t o listen h a r d , b u t t h e y h e a r d little n e w , a n d t h e speakers varied from t e d i u m to T e D e u m . Nevertheless, t h e session was valu­ able, for it displayed (1) o p p o s i n g views (or a t least opposing m e t h o d s )

on internal tidal g e n e r a t i o n b y bot­ t o m t o p o g r a p h y (M. R a t t r a y and P.G. Baines); (2) n o n l i n e a r analyses on critical layer a b s o r p t i o n , para­ metric instability, a n d m o m e n t u m flux driven b y b u o y a n c y flux in a rotating fluid ( R . G r i m s h a w , A . D . M c E w a n , a n d M.E. M a c l n t y r e ) ; (3) o c e a n response calculations with Vaisala profile a n d e d d y coefficients as p a r a m e t e r s (W. Krauss); (4) ocean o b s e r v a t i o n s on possible internal waves near oceanic f r o n t s and an energy transfer vertically a n d hori­ zontally ( N . D . Bang a n d C. Frankign o u l ) ; ( 5 ) revealing analyses of internal wave scattering b y microstructure a n d s l e n d e r - b o d y t h e o r y for a stratified fluid ( L . A . Mysak and D.G. H u r l e y ) , (6) L o c h Ness observa­ tions of an internal b o r e a n d t h e wavy s t r u c t u r e following it ( T h o r p e ) , and (7) further d e v e l o p m e n t of t h e internal wave synthesis n o w generically k n o w n as t h e G a r r e t t - M u n k spectrum ( p r e s e n t e d by N e e d i e r ) . M e l b o u r n e G. Briscoe Woods H o l e O c e a n o g r a p h i c Institution Woods H o l e , Massachusetts 0 2 5 4 3

OW-III: Circulation and Long Waves (Three Sessions) T h e S y m p o s i u m o n Circulation and L o n g Waves was carried o u t in three sessions. T h e first dealt with observations of features of t h e largescale circulation; t h e s e c o n d with circulation t h e o r y , including numer­ ical m o d e l i n g ; and t h e t h i r d with long waves, t h e material being b o t h theoretical and observational. T h e p a p e r s w e r e of m i x e d value, of course, b u t nearly all w e r e substan­ tial and useful, a n d several were par­ ticularly stimulating. Of t h e latter, one from each session is discussed in t h e following paragraphs t o illustrate t h e high level of interest occasionally reached in t h e s y m p o s i u m . K. W y r t k i (University of Hawaii, U . S . A . ) r e p o r t e d s t a t i s t i c s of m o n t h l y m e a n sea level at island sta­ tions in t h e e q u a t o r i a l Pacific: differ­ ences b e t w e e n stations correlated r e m a r k a b l y well w i t h observed sur­ face speeds of t h e N o r t h a n d S o u t h Equatorial Currents and the Equa­

torial C o u n t e r c u r r e n t , t h u s estabhshing sea level observations as valid indices of f l u c t u a t i o n s in t h e s e cur­ rents. Such correlation is e x p e c t e d , of course, from g e o s t r o p h i c b a l a n c e , yet o n e is so a c c u s t o m e d t o having t h e obvious o b l i t e r a t e d b y noise in geophysical d a t a t h a t it is gratifying to find a simple relation so e m p h a t ­ ically validated. W y r t k i goes o n t o discover equally striking c o r r e l a t i o n s b e t w e e n t i m e series of sea level dif­ ferences and variations in surface wind stress (e.g., t h e N o r t h E q u a ­ torial Current a n d t h e C o u n t e r c u r ­ r e n t are strongest in fall, w h e n t h e trade winds are weakest). It a p p e a r s t h a t he has established a s o u n d obser­ vational basis for c o n s t r u c t i n g a n a d e q u a t e d y n a m i c a l t h e o r y of varia­ tions in t h e equatorial circulation. I n t h e second session, J . S . G o d ­ frey (C.S.LR.O. Division of Fisheries and O c e a n o g r a p h y , Australia) c o n ­ sidered a two-layer m o d e l of a large, i n i t i a l l y geostrophically b a l a n c e d p a t c h of warm w a t e r and a s k e d h o w this warm p a t c h w o u l d spread o u t over t h e rest of t h e ocean w i t h dissi­ p a t i o n from lateral viscosity alone. T h e sequence of events was by n o m e a n s o b v i o u s : internal Rossby waves first t r a n s p o r t e d t h e p a t c h t o w a r d t h e western b o u n d a r y , w h e r e a strong western b o u n d a r y c u r r e n t d e v e l o p e d ; i n t e r n a l Kelvin waves t h e n advected w a r m w a t e r t o t h e e q u a t o r and along t h e e q u a t o r t o t h e eastern b o u n d a r y , t h e n p o l e w a r d , and t o w a r d t h e western b o u n d a r y again. T h u s t h e w a r m w a t e r spread o u t over t h e w h o l e ocean primarily from t h e eastern b o u n d a r y . T h i s sur­ prising m o d e l is b y n o m e a n s of aca­ demic fluid d y n a m i c a l interest o n l y , because it suggests t h a t d i s t u r b a n c e s t o t h e circulation in t h e w e s t e r n p a r t of an ocean c o u l d lead t o e a s t w a r d advection of w a r m water along t h e e q u a t o r , supplying a p o l e w a r d w a r m flow along t h e eastern boundary— t h e El N i n o p h e n o m e n o n . Large 'eddies' c u r r e n t l y engage c o n s i d e r a b l e oceanographic a t t e n ­ t i o n , and A . E . Gill (University of Cambridge, England) presented a statistical analysis of t e m p e r a t u r e data in t h e N o r t h A t l a n t i c t o d e m o n ­ strate their widespread prevalence a n d d o m i n a n t h o r i z o n t a l and vertical scale. He discussed possible sources

for t h e i r energy, ruling out several, a n d described a linear baroclinic-instability m o d e l t h a t could be fitted r a t h e r realistically t o the observed scales, and t h a t yielded e-folding times for t h e eddies of 4 - 6 months E d d i e s of t h e observed strength ap­ p e a r t o play a major role in the ener­ getics of t h e m e a n circulation in that w i t h i n t h e framework of the barocHnic-instabihty m o d e l , they extract p o t e n t i a l energy from t h e mean flow at t h e s a m e r a t e at which it is built u p b y t h e wind. Bruce A. Warren Woods Hole Oceanographic Institution W o o d s H o l e , Massachusetts 02543

AS-I: Measurement and Prediction of Sea Surface Temperature (Two Sessions) T h e first p a p e r , o n 'Aerial infrared m e a s u r e m e n t s of sea surface temper­ a t u r e , ' was mainly concerned with t e c h n i q u e s in measuring sea surface t e m p e r a t u r e ( S S T ) . T h e third paper, b y E . K . W e b b o n ' T h e cool skin of green w a t e r surfaces,' was based on general stability arguments and fol­ l o w e d t h e abstract. A paper by A.H. S c h o o l e y p r e s e n t e d results obtained in a small water-wind t a n k using thermister b e a d s of small response time t o m e a s u r e simultaneously tempera­ t u r e of t h e w a t e r a n d wet-bulb tem­ p e r a t u r e in air, w h e n t h e probe was e x p o s e d t o t h e a t m o s p h e r e while still wet. U p o n e v a p o r a t i o n of the probe's surface wetness dry-bulb tempera­ tures w e r e o b t a i n e d . T h e next paper, b y A . E . Gill, dealt w i t h t h e modeling p r o b l e m of predicting sea surface t e m p e r a t u r e s , generating a lively dis­ cussion. T h e p a p e r b y S.P. MalevskyM a l e v i c h was p r e s e n t e d by A.S. D u b o v a n d follows closely the pub­ lished a b s t r a c t . T h e a f t e r n o o n session started with t h e p a p e r b y J. A d e m , w h o reported o n a m o r e refined version of his prev i o u s m o d e l t o p r e d i c t mean m o n t h l y sea surface temperatures. H. L a c o m b e r e p o r t e d o n a simplified semiempirical m o d e l of t h e seasonal and t r a n s i e n t thermoclines, which were c o m p a r e d w i t h very impressive data o b t a i n e d in J u l y 1969 on Buoy

Laboratoire in t h e W e s t e r n Mediter­ ranean. After 12 h o u r s of winds of about 15 m / s , t h e t e m p e r a t u r e at 5 m dropped b y 4 - 5 ° C ; after 2 4 h o u r s a layer of 15-m d e p t h is well m i x e d and a Ri ^ 0.5 was e s t i m a t e d b y using the orbital m o t i o n of waves. The following p a p e r , b y G.P. Britton, stressed t h e i m p o r t a n c e of advection associated w i t h strong atmospheric systems over t h e N o r t h Atlantic by using d a t a f r o m O c e a n Weather Ships ' J ' and T.' S o m e s t u d y was presented for t h e F e b r u a r y 1969 A t l a n t i c s t o r m w i t h hurricanestrength winds. B u o y L a b o r a t o i r e data were also discussed t h a t covered a period w h e n in 4 d a y s t h e SST dropped from 24°C t o 17°C u n d e r strong wind c o n d i t i o n s . T h e last paper was p r e s e n t e d b y F . Ostapoff, who discussed q u a r t z t h e r m o m e t e r data in t h e m i x e d layer t h a t reveal nocturnal convection in t h e b u o y ­ ancy subrange. T h e b u o y a n c y time scale was calculated t o b e a b o u t 2 4 min and associated space scales t o b e about 50 m . F e o d o r Ostapoff Sea Air I n t e r a c t i o n L a b o r a t o r y National Oceanic and A t m o s p h e r i c Administration Miami, Florida 3 3 1 4 9

AS-II: Mesoscale Phenomena in the Boundary Layers of the Ocean and the Marine Atmospheres (Two Sessions) F. Ostapoff served as c h a i r m a n of Session AS-II. The first invited p a p e r was given by R.T. Pollard ( U n i t e d K i n g d o m ) , the revised title being ' D e e p e n i n g of the Oceanic Mixed L a y e r / Pollard p r o c e e d e d t o discuss t h e KrausTurner (KT) m o d e l a n d t h e PollardRines-Thompson ( P R T ) m o d e l . H e pointed o u t t h a t a l t h o u g h t h e K T model works rather well, some im­ provements need t o b e m a d e . Mainly, the determination of t h e fraction of the kinetic energy K E I t h a t is im­ parted on t h e surface a n d is con­ verted to p o t e n t i a l e n e r g y in t h e mixed layer needs i m p r o v e m e n t , a n d the omission of m e a n k i n e t i c energy may have serious c o n s e q u e n c e s . In the Pollard m o d e l , o n t h e o t h e r

h a n d , t h e a s s u m p t i o n of c o n s t a n t Richardson n u m b e r leads t o a lim­ iting t i m e scale of Vi inertial p e r i o d ; t h u s t h e kinetic energy i m p a r t e d o n t h e mixed layer drives inertial oscilla­ tions, which in t u r n will r e d u c e t h e Richardson n u m b e r leading t o t h e excitation of internal waves at t h e b o t t o m of t h e m i x e d layer. T h e ques­ tion arises as t o what kind of obser­ vations are n e e d e d to i m p r o v e mixedlayer models. Pollard singled out three t y p e s : ( 1 ) observations of t h e kind of waves t h a t are generated at t h e internal interface and of t h e wave n u m b e r s p e c t r u m ; (2) in t h e case of n o sharp interface, detailed shear a n d t e m p e r a t u r e profiles across t h e inter­ face; and (3) observations o n t h e tur­ bulence scales in t h e m i x e d layer, and possibly also flux m e a s u r e m e n t . T h e second invited paper was given by E.B. Kraus ( U n i t e d States) w h o addressed himself t o t h r e e fun­ damental p r o b l e m s of t h e trades: (1) Why are t h e trades so steady? (2) What factors determine t h e storage of heat a n d moisture in t h e trades? and (3) H o w deep in the ocean are traveling disturbances felt? T h e first question was answered b y a linear p e r t u r b a t i o n m o d e l . T h e solution shows t h a t it is n o t possible t o drive significant surface velocity p e r t u r b a t i o n s w i t h pressure p e r t u r b a ­ tions that propagate w i t h a phase velocity t h a t is either very close t o or very different from t h e velocity of t h e trades. In other w o r d s , surface velocity p e r t u r b a t i o n in t h e trades can develop only within a n a r r o w b a n d of Doppler-shifted frequencies. T h e second question was dis­ cussed with a set of conservation equations. T h e mixing c o n d e n s a t i o n level was c o m p u t e d as a function of t h e subsidence velocity, t h e wind speed, and t h e characteristics of t h e sea surface and u p p e r air. To answer t h e t h i r d question, Kraus p r o d u c e d a formula t h a t sug­ gested t h a t t h e oceanic p e n e t r a t i o n d e p t h of a t m o s p h e r i c p e r t u r b a t i o n was p r o p o r t i o n a l to t h e h o r i z o n t a l length scale multiplied by t h e ratio of t h e Coriolis and Brunt-Vaisala frequencies. H e ran out of t i m e and could not give an a d e q u a t e derivation of this expression. T h e third p a p e r , b y P r u m m (Uni­ versity of H a m b u r g ) follows exactly

t h e extensive abstract as published. T h e diurnal variation of t h e sea sur­ face t e m p e r a t u r e was p r e s e n t e d in t h e f o r m of t h e h a r m o n i c dial presen­ t a t i o n showing a m a x i m u m a r o u n d 1 6 0 0 L T . T h e a m p l i t u d e variations d e p e n d strongly o n t h e energy sup­ ply, i.e., t h e radiation balance m i n u s t o t a l h e a t flux. T h e d e p t h d e p e n ­ dence was also p r e s e n t e d in t h e f o r m of a h a r m o n i c dial. E d d y diffusion c o e f f i c i e n t as f u n c t i o n of d e p t h fitted best t h e ' H a u r w i t z spiral.' T h e meeting p r o c e e d e d after t h e coffee break with a p a p e r by J. Gonella ( F r a n c e ) entitled 'Wind a n d Near-Surface C u r r e n t C o h e r e n c e in t h e O p e n Sea.' T h e p a p e r p r e s e n t e d a modified E k m a n m o d e l and c o m ­ pared t h i s m o d e l w i t h observations in F e b r u a r y 1969 at t h e B u o y Labora­ toire in t h e western M e d i t e r r a n e a n . T h e stratification of t h e water was a b o u t A p / p « 1CT - 10"" a n d verti­ cal velocities were observed of w ~ 3 c m / s . I n s u m m e r , w h e n t h e w a t e r is strongly stratified, p r o n o u n c e d iner­ tial oscillations were observed w h e n ­ ever t h e r e was a change in t h e w i n d field. T h e result was p r e s e n t e d in t o t a l spectral p r e s e n t a t i o n as well as in t h e clockwise a n d anticlockwise s p e c t r u m . N o t a b l y in s u m m e r , all en­ ergy was c o n t a i n e d in t h e clockwise spectrum. 5

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A p a p e r b y J.W. Zillman (Austra­ lia) o n ' T h e Influence of Oceanic a n d A t m o s p h e r i c F r o n t s o n Sea-Air E n ­ ergy E x c h a n g e S o u t h of Australia' is based o n t h e Eltanin d a t a . He f o u n d t h a t t h e surface t e m p e r a t u r e of t h e A n t a r c t i c Polar front lies n o r t h ( ~ 1 0 0 miles) of t h e a c c e p t e d posi­ t i o n . F l u x m a x i m u m s were l o c a t e d near t h i s surface p o s i t i o n by using bulk formulas, a n d t h i s area was f o u n d t o be t h e region of m a x i m u m d e v e l o p m e n t of cyclones, as is evi­ d e n c e d b y satellite data. T h e last paper of t h e first m o r n i n g was given b y G.D. H a m i l t o n on t h e 'Mesoscale F e e d b a c k from t h e O c e a n t o t h e A t m o s p h e r e in Coastal a n d Oceanic F r o n t a l Regions.' A m o d e l was p r e s e n t e d t h a t dealt with t h e cases w h e t h e r surface winds m o v e from cold t o w a r m waters or vice versa. T h e model p r e d i c t s t h a t t h e air-sea t e m p e r a t u r e difference stabi­ lizes q u i c k l y ( ~ 5 h o u r s ) after being e x p o s e d t o t h e n e w surface condi-

tions. S o m e cases were s h o w n for causes of coastal fronts off Cali­ fornia. T h e s e c o n d session of AS-II on the m o r n i n g of J a n u a r y 17 was chaired b y E . B . Kraus. M. D o n e l a n (Canada) h a d changed t h e title a n d subject of his talk. He concerned himself w i t h over-water a t m o s p h e r i c b o u n d a r y layer profiles u n d e r various conditions of wind speed a n d stability. He o b t a i n e d sev­ eral h u n d r e d profiles of w i n d speed and t e m p e r a t u r e from a fixed t o w e r m o u n t e d in 12 m of w a t e r in Lake O n t a r i o . A set of empirical relation­ ships were derived from t h e s e data. E x t r e m e s of wind speed a n d stability were s h o w n t o lead t o low-level jets and anomalies in t h e profile shapes. A n i n t e r e s t i n g talk b y W.C. Patzert ( U n i t e d States) dealt with mesoscale o c e a n eddies in t h e vicin­ ity of Hawaii. T h e eddies have diam­ e t e r s of 5 0 - 1 5 0 k m . T h e y are quasi-geostrophic and have volume transports u p t o 8 X 1 0 m s . Sur­ face velocities in excess of 1 m s" are c o m m o n , t h o u g h m o s t of t h e h o r i z o n t a l flow is c o n c e n t r a t e d in the t o p 2 0 0 m . Calculations show t h a t t h e eddies cannot b e i n t e r p r e t e d as a K a r m a n vortex s t r e a m p r o d u c e d b y t h e flow of water t h r o u g h t h e gap b e t w e e n the islands. T h e y seem t o be driven b y strong winds blowing b e t w e e n t h e islands of Maui and Hawaii. O n emer­ gence from t h e restricted passage they f o r m a v o r t e x pair in t h e lee of Hawaii. E n e r g y from t h e cyclonicanticyclonic w i n d circulation is trans­ mitted t o t h e ocean eddies, which have a f o r m a t i o n t i m e of b e t w e e n 2 and 6 weeks. 6

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D. H a l p e r n ( U n i t e d States) re­ p o r t e d o n observations of t h e deep­ ening of t h e wind-mixed layer in t h e northeast Pacific during a 32-day study in A u g u s t 1 9 7 1 . A s t o r m dur­ ing t h a t p e r i o d caused d e e p e n i n g of t h e m i x e d layer from 15 t o 25 m. T h e h e a t c o n t e n t of t h e layer changed b y less t h a n 2 5 % during t h a t process. T h e s t o r m g e n e r a t e d strong currents at t h e inertial f r e q u e n c y in t h e m i x e d layer. T h e resulting veloc­ ity shear a n d t h e decrease of t h e R i c h a r d s o n n u m b e r at t h e b o t t o m of t h e layer can be related t o t h e in­ creased e n t r a i n m e n t of w a t e r from below a n d t h e d e e p e n i n g of t h e

layer. T h e investigation t h u s s e e m e d t o confirm t h e c o n c e p t s discussed b y Pollard earlier in t h e session. T h e last t a l k , b y N . Y a o a n d S. Neshyba ( O r e g o n S t a t e University, U.S.A.) was delivered b y t h e s e c o n d a u t h o r . It was of a different n a t u r e from t h e p r e c e e d i n g t a l k s , since it dealt mainly w i t h t h e m e t h o d of bispectral a n d cross-bispectral a n a l y ­ sis. T h e subject was t o o c o m p l e x for c o n d e n s a t i o n i n t o a few s e n t e n c e s . I t involves c o m p u t a t i o n of t h e F o u r i e r transference of t h e r o t a r y c o m p o ­ nents of t h e w i n d stress a n d o c e a n current vectors a n d t h e s u b s e q u e n t evaluation of s o m e of t h e first-, sec­ ond-, a n d third- o r d e r statistical m o ­ ments. Eric B. K r a u s University of Miami Miami, Florida 3 3 0 2 4 F e o d o r Ostapoff Sea Air I n t e r a c t i o n L a b o r a t o r y National Oceanic a n d A t m o s p h e r i c Administration Miami, Florida 3 3 1 4 9

AS-II: Mesoscale Phenomena in the Boundary Layers of the Ocean and the Marine Atmospheres (Two Sessions) W.C. Patzert gave a m o s t interest­ ing p a p e r on t h e f o r m a t i o n , m o v e ­ m e n t , and characteristic s t r u c t u r e of mesoscale eddies t h a t form in t h e sur­ face waters t o t h e west of t h e island Hawaii. Substantial evidence p o i n t s t o t h e i r buildup t h r o u g h energy ex­ tracted from w i n d eddies t h a t f o r m in t h e lee of t h e island, p r o b a b l y as a result of t h e c o n s t r i c t i o n of t h e trades b e t w e e n Maui a n d Hawaii. After 2 weeks ( o r m o r e ) of s e t u p , during which upweUing is clearly evi­ d e n t in the d o m i n g of i s o t h e r m s in t h e center, t h e o c e a n e d d y breaks away, moves w e s t w a r d at a n o m i n a l speed of 5 c m / s , m a i n t a i n s quasig e o s t r o p i c balance, a n d t e n d s t o b e c o m e m o r e circular, w i t h d i a m e t e r typically 5 0 - 1 5 0 k m . Lifetimes of t h e eddies are in excess of 3 m o n t h s . A l t h o u g h shallow in d e p t h , t h e indi­ vidual e d d y m a y contain in excess of 10 ergs of energy. Seeing t h e s e 12

excellent data was a great help to the a p p r e c i a t i o n of other conference p a p e r s o n ocean eddies, and to an u n d e r s t a n d i n g of t h e concern with eddies in t h e p l a n n i n g of Mode. Gate a n d o t h e r research. P a p e r s b y D . Halpern, J. Gonella, and R . T . Pollard dealt with the c o u p l i n g b e t w e e n w i n d stress and the near-surface c u r r e n t a n d / o r the ocean m i x e d layer. T h e Halpern paper was o n e of t h o s e rare cases in which a t h o r o u g h analysis is made of a rela­ tively s u p e r i o r set of records of both t h e surface w i n d and the tempera­ t u r e s a n d c u r r e n t s at several levels s p a n n i n g t h e m i x e d layer depth and t h e stratified t h e r m o c l i n e zone. Re­ sults s h o w clearly t h e effects of a passing s t o r m front o n t h e homogeniz a t i o n of t h e m i x e d layer (previously w e a k l y stratified) and t h e deepening of t h e m i x e d layer in coherence with t h e d r o p in t h e d y n a m i c stability of t h e interface w i t h t h e stratified fluid; f u r t h e r , s y s t e m energetics agrees r e a s o n a b l y well w i t h theoretical pre­ d i c t i o n s . Pollard presented a thesis in s u p p o r t of t h e need in future experi­ m e n t s t o e x a m i n e closely the spectral n a t u r e of waves o n t h e interface b e t w e e n t h e m i x e d layer and the stratified z o n e b e l o w , and for re­ lating t h i s s p e c t r u m to t h a t of turbu­ lence in t h e m i x e d layer. Gonella p o i n t e d o u t t h e need for a revised E k m a n h y p o t h e s i s , basing his argu­ m e n t o n t h e a p p r o a c h t h a t , although t h e E k m a n h y p o t h e s i s says that these m u s t b e inertial oscillations gener­ a t e d in a h o m o g e n e o u s ocean under t r a n s i e n t c o n d i t i o n s , he has found no inertial oscillations in t h e Mediter­ r a n e a n during w i n t e r conditions when t h e w a t e r is nearly homogeneous. Still a n o t h e r factor was evident in t h e H a l p e r n , Gonella, and YaoN e s h y b a p a p e r s : t h a t of the spectral analyses of geophysical vector pro­ cesses b y m e a n s of t h e rotary compo­ n e n t m e t h o d . Clearly, this has be­ c o m e a useful t e c h n i q u e of analysis. T h e Y a o a n d N e s h y b a paper has carried t h e spectral analysis of the c o u p l e d w i n d stress ocean current p r o b l e m o n e step further by demon­ strating t h e statistical significance of t h e n o n l i n e a r , q u a d r a t i c interactions w i t h i n t h e c o u p l e d system. It appears t o b e a useful m e t h o d of studying a c o u p l e d system in w h i c h the vector processes,' n o w k n o w t o be non-

Gaussian, interact over w i d e ranges of frequencies. C a u t i o n in i n t e r p r e t a ­ tions is also clearly r e q u i r e d . Two papers, b y J.W. Z i l l m a n a n d by G.D. Hamilton, K. R a b e , a n d T . Laevastu, dealt w i t h t h e influence of ocean thermal fronts in t h e modifica­ tion of atmospheric processes. Zill­ man showed a clear r e l a t i o n b e t w e e n the zones of cyclone f o r m a t i o n a n d the strong t h e r m a l g r a d i e n t s off t h e southern Australian c o a s t ; H a m i l t o n , Rabe, and Laevastu s h o w e d similar phenomena occurring in t h e Gulf S t r e a m - L a b r a d o r C u r r e n t frontal area. Still a n o t h e r set of p a p e r s e x a m ­ ined the variability in t h e a t m o ­ spheric b o u n d a r y layer. M. D o n e l a n presented results of an excellent field program in L a k e O n t a r i o f r o m w h i c h the variations in t h e a t m o s p h e r i c boundary were studied. T h e P r u m m paper presented an elegant a p p r o a c h to the c o m p u t a t i o n of t h e t h e r m a l diffusivity coefficient in t h e ocean surface layer b y use of a h a r m o n i c analysis of t h e diurnal t e m p e r a t u r e variance at successive d e p t h s . Steve N e s h y b a Department of O c e a n o g r a p h y Oregon State University Corvallis, Oregon 9 7 3 3 0

AS-III: Air-Sea Interaction in Synoptic and Climatic Development (Three Sessions) The Air-Sea I n t e r a c t i o n s y m p o ­ sium i n c l u d e d t h r e e sessions, in which t h i r t e e n papers were pre­ sented, most b u t n o t all of w h i c h were relevant t o t h e t o p i c . T h e talks were for t h e m o s t p a r t stimulating, and the discussions w e r e often inter­ esting and livery. T h e p a p e r s fell largely into t h r e e categories: (1) o b ­ servational studies, (2) m o d e l studies, (3) a n d m i s c e l l a n e o u s . U n f o r t u ­ nately, t w o of t h e p a p e r s (W.L. Gates, K. Bryan and S. M a n a b e ) m o s t suited t o trace t h e c o n n e c t i o n be­ tween (1) and (2) were w i t h d r a w n . L Namias ( U n i t e d S t a t e s ) began the session w i t h a discussion of his ideas regarding m o n t h l y a n d seasonal abnormalities resulting f r o m a t m o ­ sphere-ocean coupling. T h e basic tenet of his a r g u m e n t is t h a t t h e

development a n d m o v e m e n t of a m o n t h l y m e a n m i d tropospheric t r o u g h is associated w i t h and p e r h a p s explained b y t h e presence of sea sur­ face t e m p e r a t u r e contrasts existing in t h e N o r t h Pacific. T h e q u e s t i o n is w h e t h e r t h e sea s o m e h o w ' c o n d i ­ tions' t h e a t m o s p h e r e or vice versa. Obviously, t h e t u n i n g is quite c o m ­ p l e x , but t h e r e are u n d o u b t e d l y quite intriguing correlations b e t w e e n atmospheric a n d sea surface a n o m a ­ lous p h e n o m e n a . R . Dickson ( U n i t e d K i n g d o m ) discussed observations of t r e n d s in hydrographic d a t a from t h e N o r t h Atlantic t h a t seem t o s h o w u p all over t h e region. Periodicites of 6 - 7 years show u p clearly in t h e data. Dickson suggests (following Namias) t h a t these widespread a n o m a l o u s p a t t e r n s m a y b e due t o a single dis­ t o r t i o n of t h e natural a t m o s p h e r i c p a t t e r n . W h e t h e r t h e r e is i m p o r t a n t feedback from ocean t o a t m o s p h e r e is n o t clear at present, b u t t h e nearly simultaneous occurrence of a n o m a ­ lous events in t h e ocean a n d a t m o ­ sphere make t h e p r o b l e m an i m p o r ­ t a n t one t o unravel. A p p a r e n t l y synchronous events are occurring in t h e Pacific sector as well, suggesting t h a t events in t h e N o r t h A t l a n t i c m a y be related t o ' u p s t r e a m ' events in t h e Pacific. A paper by P . Hupfer (East Ger­ m a n y ) , presented by K. B e r n h a r d t , examined climatic fluctuations in t h e Baltic Sea during t h e last 7 0 years o n t h e basis of m o n t h l y m e a n s in t e m ­ perature and salinity. T h e influence of t h e a t m o s p h e r e on t h e Baltic Sea is m a r k e d and is of great i m p o r t a n c e t o t h e renewal of t h e Baltic Sea. T h e question of a possible feedback t o t h e a t m o s p h e r e was n o t discussed. R. Simpson and W.K. D o w n e y (Australia) p e r f o r m e d m o d e l experi­ m e n t s , using t h e s o u t h e r n hemi­ sphere version of t h e G F D L GCM, t o add t o t h o s e b y R o w n t r e e a n d Spar in t h e N o r t h e r n Hemisphere. T w o e x p e r i m e n t s were r u n : a c o n t r o l experiment in which observed sea surface t e m p e r a t u r e p a t t e r n s were used and a second e x p e r i m e n t in which a sea surface a n o m a l y was in­ troduced. The anomaly had a maxi­ m u m intensity of + 4 ° C centered near New Zealand. T w o 30-day integra­ tions were c o m p a r e d and several re­ sults were f o u n d : (1) t r o u g h and

ridge s y s t e m s were displaced even in t h e I n d i a n O c e a n , b u t major changes were n e a r t h e a n o m a l y ; ( 2 ) t h e r e was a preferred tracking of cyclones; ( 3 ) b l o c k i n g situations w e r e e n c o u r a g e d in t h e a n o m a l y case. A major p o i n t b r o u g h t u p in discussion by W.W. Kellogg ( U n i t e d States) was t h a t these k i n d s of e x p e r i m e n t s contain a certain a m o u n t of noise or natural variability, a n d as a result, signals from o n e single e x p e r i m e n t m a y n o t be entirely meaningful. It w o u l d seem t h a t m a n y cases w o u l d be necessary t o pin d o w n t h e effects of such a n a n o m a l y , a n d it is n o t en­ tirely clear t h a t t h e GCM's are well suited for this task. I n place of t h e e x p e c t e d paper b y K. B r y a n a n d S. M a n a b e , J.S. Sawyer ( U n i t e d K i n g d o m ) gave a brief dis­ cussion concerning w h e t h e r m a n ' s waste h e a t can affect t h e climate o n a global basis. H e a t b a l a n c e estimates in an a n o m a l o u s p a t c h of w a r m water indicate it gives u p a b o u t 4 0 w a t t s / m . This c o m p a r e s with R o w n tree's results of 120 w a t t s / m for a 3.8°C a n o m a l y . T h u s o n e might t a k e about 50 w a t t s / m as a marginal value above which t h e climate might be u p s e t . A t t h e p r e s e n t t i m e t h e heat o u t p u t b y t h e U n i t e d States a n d w e s t e r n E u r o p e is o n l y a b o u t 1 w a t t / m , a n d at a 5% p e r year in­ crease it will take 4 3 years t o r e a c h 10 w a t t s / m . T h u s m a n ' s waste h e a t is p r o b a b l y n o t a p r o b l e m at p r e s e n t . A . Gilchrist ( U n i t e d K i n g d o m ) discussed an interesting m o d e l for a variable d e p t h b o u n d a r y layer t o be i n c l u d e d in general circulation m o d ­ els. T h e m o d e l is designed t o deter­ m i n e t h e passage of heat a n d mois­ t u r e from t h e b o u n d a r y layer i n t o t h e free a t m o s p h e r e w i t h a m i n i m u m a m o u n t of c o m p u t a t i o n . W.C. Patzert ( U n i t e d States) p r e ­ s e n t e d s o m e ideas c o n c e r n i n g m e c h ­ anisms for El N i n o . Basically t h e El N i n o s i t u a t i o n is r e l a t e d t o a largescale weakening in t h e southeast t r a d e s , w h i c h allows s t r e n g t h e n i n g of the S o u t h Equatorial Countercurr e n t . Warm water is t h e n advected into t h e coastal region of Peru. D a t a suggests El N i n o p r o b a b l y occurs at t h e tail e n d of t h e p e r i o d of larges c a l e anomalies t h a t Namias h a s shown. K. T r e n b e r t h ( N e w Zealand) dis­ cussed t h e relationship b e t w e e n o b 2

2

2

2

2

serrations of m o n t h l y m e a n sea level pressure (SLP) anomalies In t h e Aus­ tralasian area a n d m o n t h l y m e a n sea surface t e m p e r a t u r e (SST) anomalies in t h e T a s m a n sea. He suggests there is a strong quasi-biennial periodicity with an a m p l i t u d e of 2.5 m b a r in t h e m o n t h l y m e a n SLP a n o m a l y field and 0.4°C in t h e m o n t h l y m e a n SST anomaly field. It appears likely t h a t t h e SST field is largely caused b y t h e SLP field; t h e r e is no a p p a r e n t feed­ back. E. K r a u s (United S t a t e s ) gave a provocative discussion regarding in­ teracting a t m o s p h e r e - o c e a n circula­ tion regimes based o n a zonally symmetric m o d e l . He a t t e m p t e d a quite c o m p l e x chain of reasoning based o n n u m e r i c a l e x p e r i m e n t s and analytical reasoning t o explain ice age differences from p r e s e n t day re­ gimes. W.R. Holland and H. Friedrich (United States) discussed 3-D nu­ merical results of a seasonally driven ocean m o d e l . T h e results indicate a quite realistic response of t h e sea­ sonal cycle in t h e u p p e r o c e a n , b u t t h e m o d e l has n o t y e t b e e n a p p h e d to interacting ocean-atmosphere systems. M. Z o r e-Armanda (Yugoslavia) e x a m i n e d year t o year variations in ice cover o n t h e sea in t h e n o r t h e r n h e m i s p h e r e . T h e v o l u m e of ice cover is t h o u g h t t o be related t o a series of changes in t h e sea a n d a t m o s p h e r e , b u t it is n o t clear w h e t h e r it is a re­ sult or a cause of such changes. D. J o h n s o n (United States) dis­ cussed a m o d e l for cyclogenesis af­ fected b y sensible h e a t addition. When t h e r e is strong sensible heat transfer from ocean t o a t m o s p h e r e , t h e a t m o s p h e r e changes f r o m one w i t h little coupling b e t w e e n b o u n d ­ ary layer a n d free a t m o s p h e r e to one w i t h s t r o n g coupling. T . P . B a r n e t t ' s ( U n i t e d States) p a p e r on t e l e c o n n e c t i o n s in t h e N o r t h Pacific basin was p r e s e n t e d b y W.B. W h i t e . It is d e m o n s t r a t e d t h a t t i m e d e p e n d e n c e in sea surface t e m ­ p e r a t u r e , m o m e n t u m in t h e a t m o ­ sphere, a n d sea level p r e s s u r e differ­ ences are all i n t e r c o n n e c t e d , b u t it is all terribly c o m p l i c a t e d . T h e statis­ tical results are o b s c u r e , b u t some q u a n t i t i e s a p p a r e n t l y are signifi­

cantly years.

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William R. H o l l a n d Geophysical F l u i d D y n a m i c s Laboratory N a t i o n a l Oceanic a n d A t m o s p h e r i c Administration P r i n c e t o n , N e w Jersey 0 8 5 4 0

AS-IV-3: Direct Measurement of Fluxes and Wind Speed Near the Surface V. Mitsuta began t h e session b y reporting on high-frequency m e a s u r e ­ m e n t s with several acoustic a n e m o m ­ e t e r - t h e r m o m e t e r s at t h r e e sites: a land site in J a p a n , a J a p a n e s e lake, and o n the 5 0 0 - m t o w e r at Okla­ h o m a City. T h e accuracy of t h e m e a s u r e m e n t s was d e m o n s t r a t e d b y t h e fact that t h e h e a t b u d g e t at t h e surface balanced t o within 2%. Most of t h e effort w e n t i n t o m e a ­ surement of vertical fluxes a n d t h e i r spectral distributions. F r e q u e n c y dis­ t r i b u t i o n s of h e a t flux a n d stress w e r e significantly different from each other. Variances of vertical ve­ locity and t e m p e r a t u r e u n d e r convec­ tive conditions agreed well w i t h p r e ­ dictions from similarity t h e o r y . N . T h o m p s o n r e p o r t e d o n mea­ surements over t h e ocean by t e t h e r e d balloon in a very moist b o u n d a r y layer. M e a s u r e m e n t s of m o i s t u r e flux and t e m p e r a t u r e flux were m a d e at 65 and 160 m . T h e m e a s u r e m e n t s showed that t h e b u o y a n c y was mois­ t u r e driven. T h e h e a t flux reversed sign and b e c a m e negative at t h e u p p e r level; t h e m o i s t u r e flux did n o t . T h e e x p l a n a t i o n is t h a t a d r y , warm layer lies over t h e b o u n d a r y layer so t h a t e n t r a i n m e n t from a b o v e (at t h e t o p of t h e layer) associates d o w n w a r d m o t i o n w i t h high t e m p e r ­ atures b u t low specific h u m i d i t i e s . Panofsky discussed m e a s u r e m e n t s of coherence b e t w e e n w i n d speeds on masts in L a k e O n t a r i o w i t h sepa­ rations of a b o u t 50 and 100 m . Co­ herence decreases e x p o n e n t i a l l y w i t h ratio of separation t o wavelength. According t o T e n n e k e s , t h e coher­ ences should fall off w i t h distance m o r e rapidly over r o u g h t h a n s m o o t h terrain. This h y p o t h e s i s was b o r n e

o u t b y t h e observations over the lake, w h e r e t h e coherence was re­ m a r k a b l y high w h e n t h e wind blew along t h e a n e m o m e t e r line and the w a t e r was w a r m e r t h a n the air. In n e u t r a l and stable conditions, the c o h e r e n c e decays rapidly as the angle b e t w e e n wind a n d anemometer line increases. T a y l o r ' s hypothesis that t h e e d d i e s travel w i t h t h e wind speed fitted t h e observations well. G. K r u s p e r e p o r t e d on measure­ m e n t s of vertical fluxes of heat and m o i s t u r e over t h e N o r t h Sea and Baltic. As usual, vertical velocity spectra were quite variable, often w i t h l o w frequencies lacking-in a g r e e m e n t w i t h B o m e x results. In spite of t h e difference in the behav­ ior of m o i s t u r e and temperature, ver­ tical fluxes of h e a t and moisture had essentially t h e same spectral compo­ s i t i o n ; similarly, exchange coeffi­ cients for heat and moisture were equal, so t h a t Bo w e n ratios could be e s t i m a t e d from vertical gradients of p o t e n t i a l t e m p e r a t u r e and specific humidity only. F . F . Hall discussed measurements by himself a n d his co-workers with acoustic s o u n d e r s at Haswell, Colo­ r a d o , a site at w h i c h a meteorological t o w e r is also located. I n t h e first e x p e r i m e n t , an acous­ tic s o u n d e r was directed vertically, t h u s r e s p o n d i n g t o high-frequency t e m p e r a t u r e fluctuations, so that the structure constant could be deter­ m i n e d . E x c e p t for early morning r u n s , s u c h s t r u c t u r e constants deter­ m i n e d from t h e g r o u n d agreed well w i t h t h e same c o n s t a n t s measured on t h e t o w e r . A l s o , h e a t flux estimates could b e m a d e from t h e remote mea­ surements. I n t h e second experiment, Doppler s o u n d e r s were used t o sense ve­ locities. Time-average velocities were e s t i m a t e d well from t h e ground. But f l u c t u a t i o n statistics sensed remotely p r o v e d largely unsatisfactory. R . L . Street r e p o r t e d o n measure­ m e n t s m a d e by himself and his asso­ ciates in t h e wind-water tunnel at S t a n f o r d University. T h e water was h e a t e d , a n d various t y p e s of waves could b e p r o d u c e d . In contrast to K r u s p e ' s m e a s u r e m e n t s in the atmo­ sphere over w a t e r , exchange coeffi­ cients for h e a t and m o i s t u r e were not t h e s a m e , b u t t h o s e for momentums

and moisture were e q u a l t o each other. Also, in m a n y o t h e r ways, fluxes of moisture a n d h e a t had dif­ ferent properties, r e s p o n d i n g , for example, d i f f e r e n t l y t o wave changes. V o n K a r m a n ' s c o n s t a n t was evaluated and averaged 0 . 3 9 , in g o o d agreement with full-scale experi­ ments. Bernhardt s u m m a r i z e d results of measurements m a d e b y P . H u p f e r and his colleagues at t h e Baltic Coast of the Democratic R e p u b l i c of Ger­ many. T e m p e r a t u r e s w e r e o b t a i n e d in the lowest 25 cm of t h e air above the sea, by a fast-response resistance thermometer w i t h a t e m p e r a t u r e res­ olution of 0.02°C. Particular emphasis was placed o n the temperature d i s t r i b u t i o n in t h e lowest millimeter, w h e r e t h e flow is laminar and t h e t e m p e r a t u r e changes rapidly. As was p r e d i c t e d , t h e thick­ ness of this laminar l a y e r was in­ versely p r o p o r t i o n a l t o t h e friction velocity. Also, heat fluxes w e r e d e t e r m i n e d from the t e m p e r a t u r e gradients in the laminar layer; t h e s e , h o w e v e r , did not agree well with h e a t fluxes mea­ sured by conventional t e c h n i q u e s at 4 m. Possible reasons for these dis­ crepancies were discussed. Hans A . Panofsky College of E a r t h and Mineral Sciences Pennsylvania State University University Park, Pennsylvania 1 6 8 0 2

G-3: Gate The first t h r e e s p e a k e r s , J. K u e t t ner, H. Kraus, and Y u T a r b e e v p r e ­ sented t h e current s t a t u s of planning for the scientific a n d o p e r a t i o n a l as­ pects of t h e Garp A t l a n t i c Tropical Experiment ( G a t e ) . T h e scientific plan is now c o m p l e t e , w i t h publica­ tions being issued b y t h e World Mete­ orological Organization (WMO) o n details. In order t o k e e p t h e focus o n the basic objectives as set o u t by t h e International Council of Scientific Unions (ICSU)/WMO J o i n t Organiz­ ing C o m m i t t e e for G a r p , a central program was developed t o plan t h e observationl effort t o o b t a i n g o o d data sets o n all scales of heat, m o ­ mentum, and m o i s t u r e t r a n s p o r t .

These data sets will m a k e it possible to study t h e scale interactions a n d t o express those o n the smaller scale in t e r m s of t h e measured p a r a m e t e r s on t h e larger scale. In order to m a k e planning of this complex e x p e r i m e n t possible, t h e central program was divided i n t o five subprograms: synoptic, convective, b o u n d a r y layer, radiation, a n d ocean­ ography. In each subprogram t h e scientific p r o b l e m s related to the main objectives were used as guides t o plan observational strategy t o ob­ tain data sets u n d e r t h e variety of conditions n e e d e d t o parameterize t h e scale interactions. Data from t h e various national participants will be processed na­ tionally, some flowing to operational headquarters at Dakar in near real time for use in c o n d u c t of t h e experi­ m e n t . T h e nationally processed data sets will be merged at five subpro­ gram data centers: s y n o p t i c at Brack­ nell; convective at Washington, D . C ; b o u n d a r y layer at H a m b u r g ; radia­ tion at Leningrad; and o c e a n o g r a p h y at Brest. A t t e m p t s will be m a d e t o have this basic collection c o m p l e t e d within 6 m o n t h s of t h e end of G a t e , and merging of data i n t o consistent data sets will take the next 18 m o n t h s . However, data for s t u d y of selected cases will be available t o t h e scientific c o m m u n i t y o n a continuing basis, once merging c o m m e n c e s . T h e details of t h e s u b p r o g r a m s are complex and can be s u m m a r i z e d here only superficially. T h e reader is re­ ferred to t h e G a t e Publication Series, WMO, for full details. The b o u n d a r y layer fluxes o u t of t h e ocean surface layer into the atmosphere, a n d especially into t h e organized convective systems, and t h e changes of t e m p e r a t u r e s and moisture in t h e transitional layer at cloud base are of p a r a m o u n t i m p o r ­ tance. T h e plan for convection studies emphasizes t h e detailed d o c u m e n t a ­ tion of all convective p h e n o m e n a , different kinds of i n t e r a c t i o n be­ tween scales, a n d data sets for testing new and improved models of convec­ tive systems. Radiation m e a s u r e m e n t s will p r o ­ vide t h e possibility t o calculate bud­ gets for l a t e n t and sensible heat averaged over an area containing convective systems, using flux mea­

s u r e m e n t s at t h e surface and t o p of t h e a t m o s p h e r e as c o n t r o l s . A major goal is t o p a r a m e t e r i z e t h e a t m o ­ spheric h e a t budget during disturbed conditions. Oceanographic studies are some­ w h a t broader t h a n t h o s e n e e d e d strictly for G a t e objectives, b u t t h e y are also generally related to b r o a d e r Garp n e e d s . T h e y include s t u d y of t h e larger-scale p h e n o m e n a such as t h e e q u a t o r i a l u n d e r c u r r e n t , smallerscale i n t e r a c t i o n s of a t m o s p h e r e a n d ocean o n t h e scale of t h e convective systems, a n d small-scale p h e n o m e n a s u c h a s w a v e - a t m o s p h e r e inter­ actions, f o r m a t i o n s of o c e a n fronts, and variability of t h e m i x e d layer. T h e observational forces being d e p l o y e d for G a t e represent t h e largest geophysical effort ever p u t t o g e t h e r for one c o o r d i n a t e d experi­ m e n t : 3 7 well-equipped ships, m o s t of w h i c h will m a k e b o t h a t m o s p h e r i c and oceanographic observations; 12 research aircraft; s o m e 2 0 b u o y s ; a n d extra efforts b y a b o u t 100 land sta­ tions. Special b o u n d a r y layer t e t h ­ ered b a l l o o n s and s t r u c t u r e sondes have b e e n developed for Gate, a n d m e t e o r o l o g i c a l radars were installed o n s o m e ships. T h e e n t i r e p e r i o d of observations is from J u n e 15 t o S e p t e m b e r 2 7 , with t h r e e 21-day in­ tensive periods w h e n all ships are o n s t a t i o n ; several ship a n d aircraft int e r c o m p a r i s o n periods have also b e e n p l a n n e d . A n elaborate t e l e c o m m u n i ­ c a t i o n n e t w o r k using six collector ships has been arranged to feed t o D a k a r data needed for t h e scientific c o n d u c t a n d safety of t h e experi­ ment. T. V o n d e r H a a r a n d S. Cox p r e ­ s e n t e d additional details o n t h e radia­ t i o n s u b p r o g r a m . T h e radiative h e a t ­ ing/cooling is very i m p o r t a n t in t h e t r o p i c s , since h o r i z o n t a l t e m p e r a t u r e gradients are quite small ( a b o u t o n e fifth of t h o s e f o u n d at mid-lati­ t u d e s ) , and therefore an elaborate observing system is p l a n n e d t o o b t a i n t h e b o u n d a r y flux v o l u m e (surface and t y p e of a t m o s p h e r e ) ; in situ mea­ s u r e m e n t s will b e m a d e with bal­ l o o n s , sondes, and aircraft. C l o u d s and m o i s t u r e c o n t e n t , a n d t o s o m e e x t e n t aerosols, will also be m e a ­ sured. T h e main observational phases of t h e radiation s u b p r o g r a m will b e used t o b r o a d e n t h e scientific objec­ tives, e.g., to provide d a t a sets t o t e s t

i m p r o v e d numerical m e t h o d s of treating radiation in general circula­ tion m o d e l s , and to test a n d improve r e m o t e sensing techniques. However, not all p a r a m e t e r s are possible to ob­ serve o n t h e t i m e and space scales needed; h e n c e an elaborate analysis scheme m u s t be e m p l o y e d t o calcu­ late t h e space and t i m e averages needed w i t h a d e q u a t e representative­ ness for a variety of sea-surface tem­ peratures w i t h respect t o t h e trades and t h e l o c a t i o n of t h e intertropical c o n v e r g e n c e z o n e ( I T C Z ) , the mapping of vertical sections that make it possible t o identify t h e levels of divergence a n d convergence u n d e r a variety of c o n d i t i o n s , a n d t h e dis­ covery t h a t large convective ensem­ bles p r o d u c e zonal as well as meridi­ onal c o n v e c t i o n cells. T h e vertical m o t i o n s on each side of t h e ITCZ indicate a non-Hadly circulation, and interesting wave p h e n o m e n a were found w i t h periods of 12 a n d a b o u t 50 and 77 h o u r s . Stanley R u t t e n b e r g National C e n t e r for A t m o s p h e r i c Research Boulder, C o l o r a d o 8 0 3 0 2

G-4: Satellite Techniques D.Q. Wark and W.L. S m i t h pre­ sented results of analyses of United States o p e r a t i o n a l and e x p e r i m e n t a l satellites (respectively) w i t h emphasis o n s o u t h e r n h e m i s p h e r e features. T e m p e r a t u r e retrieval p r o b l e m s are n o t y e t c o m p l e t e l y resolved for s o u t h e r n h e m i s p h e r e observations, owing t o sparse surface-based data for a reliable first-guess field or good historical data for a regression analy­ sis. Nevertheless, in t h e great datasparse regions, m u c h useful new information is a d d e d , m a k i n g it pos­ sible to r e c o n s t r u c t circulation maps of t h e lower s t r a t o s p h e r e as well as t h e t h i c k n e s s of t h e 1000- t o 5 0 0 - m b a r layer. It is difficult as y e t , however, t o locate t h e t r o p o p a u s e a n d d e t e r m i n e t h e t e m p e r a t u r e t h e r e . Areas of par­ tial cloudiness can be t r e a t e d b y sta­ tistical m e t h o d s , and b y assuming t h a t t h e h o r i z o n t a l cloudiness varies much more than the temperature, and t h u s useful t e m p e r a t u r e profiles

are retrieved. Areas of layer-scale c l o u d i n e s s , however, frustrate re­ trieval. Sea surface t e m p e r a t u r e m a p s de­ rived every t h r e e days s h o w g o o d correlation w i t h observations w h e r e t h e y exist, analyses of c i r c u l a t i o n at 5 0 0 and 3 0 0 m b a r shows g o o d cor­ respondence w i t h frontal s y s t e m s , and t o t a l w a t e r c o n t e n t analyses agree with e x p e c t e d d i s t r i b u t i o n s in frontal systems. C u r r e n t p e r f o r m a n c e indicates rms deviations of a b o u t 2°C t h r o u g h m o s t of t h e t r o p o s p h e r e , b u t layer deviations near t h e t r o p o p a u s e a n d d e r i v e d g e o p o t e n t i a l heights show a s t a n d a r d deviation of a b o u t 50 m . T h e n a t u r a l variability as mea­ sured with r a d i o s o n d e s and as deter­ m i n e d from derived t e m p e r a t u r e profiles are quite c o m p a r a b l e in na­ ture and m a g n i t u d e , e x c e p t at t h e t r o p o p a u s e . Retrieval of useful t e m ­ peratures averages 9 5 % coverage w i t h h o r i z o n t a l resolution of 5 0 0 X 5 0 0 k m . T h e new s o u n d e r c o m p l e x t o be launched later this year on N i m b u s 6 will be a significant step t o w a r d achieving t h e i m p r o v e d p e r f o r m a n c e needed t o m e e t t h e r e q u i r e m e n t s of the global e x p e r i m e n t in 1 9 7 7 / 1 9 7 8 . T h e paper of R. Deland offered a useful suggestion of deriving t e m p e r ­ ature fields from spatial d a t a b y using spectral analysis t e c h n i q u e s , although t h e a s y n o p t i c n a t u r e of t h e observations m a y i n t r o d u c e p r o b ­ lems. A . F y m a t p r e s e n t e d a brief discus­ sion of obtaining size d i s t r i b u t i o n of cloud particles f r o m an analysis of a narrow-field-of-view d e t e c t o r fixed in t h e near-forward direction, m a k i n g observations in several spectral re­ g i o n s . T h e s i m u l a t e d inversions agreed well w i t h t h e a s s u m e d size s p e c t r u m , a n d t h e m e t h o d is usable in t h e presence of noise (e.g., Mie scattering) u p t o a b o u t 1 0 - 1 5 % . A m e t h o d of obtaining q u a n t i t a ­ tive i n f o r m a t i o n from cloud p a t t e r n s was discussed b y G. Kelly. T h e G a r p Basic Data Set of N o v e m b e r 1 9 6 9 was used to verify r e f i n e m e n t s of t h e ' b o g u s ' t e c h n i q u e t h a t has b e e n u s e d operationally. T h e circulation p h e ­ n o m e n a as revealed in t h e c l o u d images can be used b y a t r a i n e d t e c h nician/analyst. The need was stressed, however, for m u c h m o r e real data in t h e o p e n areas of t h e

s o u t h e r n h e m i s p h e r e , especially from clean surface b u o y s and constantlevel b a l l o o n s . A . Neal p r e s e n t e d the results of a d d i t i o n a l studies based on the Garp Basic D a t a Set of J u n e 1970, com­ p a r i n g cloud a n d conventional obser­ v a t i o n s w i t h N i m b u s 4 observation of w a t e r v a p o r in t h e midtroposphere using t h e 6,7 pm channel. The water v a p o r d i s t r i b u t i o n showed good cor­ r e l a t i o n w i t h t h e position of jet s t r e a m circulations. When the circula­ t i o n p a t t e r n s of water vapor were a n a l y z e d and separated into those a p p e a r i n g t o t r a n s p o r t vapor from f r o m high latitudes and those trans­ p o r t i n g vapor from low latitudes, it was f o u n d t h a t t h e r e were four pre­ ferred circulations from the tropics, o n e of w h i c h (from India to western Australia) a p p a r e n t l y was not asso­ ciated w i t h visible cloudiness. The a u t h o r , however, cautioned that one m o n t h ' s w o r t h of observation is h a r d l y sufficient for drawing any lasting conclusions. Stanley Ruttenberg N a t i o n a l C e n t e r for A t m o s p h e r i c Research Boulder, Colorado 80302

DC: Deep Convection (Three Sessions) I n an a t t e m p t t o bring together t h o s e i n t e r e s t e d in t h e structure of c o n v e c t i o n i n t h e atmospheric b o u n d a r y layer, those working on deep c o n v e c t i o n in t h e sea, and those i n t e r e s t e d generally in t h e fluid dy­ n a m i c s of p e n e t r a t i v e convection at large R a y l e i g h n u m b e r , B.R. Morton ( M o n a s h University) organized the j o i n t I A M A P / I A P S O Symposium on Deep C o n v e c t i o n . There were three sessions: t h e first was o n atmospheric c o n v e c t i o n a n d t h e third on oceanic c o n v e c t i o n ; t h e s e c o n d , bridging the g a p b e t w e e n meteorologists and o c e a n o g r a p h e r s , was concerned with t h e geophysical fluid dynamics of convection. Seven papers ranging from numer­ ical m o d e l s t o field measurements were p r e s e n t e d in t h e atmosphere session. C.E. C o u l m a n showed from re­ sults of aircraft measurements in a

convective layer b e n e a t h a n inversion that heat transfer t o t h e layer could be accounted for if t u r b u l e n t d o w n ­ ward transport by e d d y diffusion were assumed t o t a k e p l a c e . M J . M a n t o n used W a r n e r and Telford's observations t o develop a model of an a t m o s p h e r i c c o n v e c t i o n cell in which t h e h o r i z o n t a l scale is small compared w i t h its height. He also showed t h a t t u r b u l e n t diffusion plays an insignificant role in t h e h e a t transport process of s u c h a cell. N . I . Vulfson a n d L.M. Levin argued that present data o n convec­ tive motion in t h e a t m o s p h e r e d o n o t allow determination of t h e shape of these flows. T h e y m a d e a t h e o r e t i c a l analysis in which t h e y c o m p a r e d rising thermal b u b b l e s t o j e t s a n d concluded t h a t in an u n s t a b l e a t m o ­ sphere convective m o t i o n is p r o b a b l y in the form of p l u m e s o r c o l u m n s rather t h a n of b u b b l e s . M.W. Moncrieff d e v e l o p e d dy­ namic models of c u m u l o n i m b u s con­ vection and s h o w e d t h a t t h r e e re­ gimes could be identified o n t h e basis of their R i c h a r d s o n n u m b e r . F o r - VA < -Ri < 1, steady t w o - d i m e n s i o n a l convection similar t o t h a t in frontal regions can t a k e p l a c e ; for -Ri > 1, unsteady convection similar t o t h a t of c u m u l o n i m b u s c l o u d s outside frontal regions can t a k e place; a n d for -Ri > 2, steady t h r e e - d i m e n ­ sional convection, w h i c h can b e iden­ tified with s o m e t r o p i c a l squall lines, can take place. M.J. Miller described t h e t h r e e d i m e n s i o n a l n u m e r i c a l m o d e l of cumulonimbus c o n v e c t i o n b y m e a n s of which t h e f o r e m e n t i o n e d conclu­ sions were derived. R. Del Beato s h o w e d t h a t satellite observations reveal mesoscale organi­ zation of a t m o s p h e r i c c o n v e c t i o n over the sea. A . A . B a r k e r p r e s e n t e d a new parameterization s c h e m e for atmospheric c o n v e c t i o n t h a t was based on a cloud m o d e l a n d s h o w e d that the p a r a m e t e r i z a t i o n could sig­ nificantly change t h e p r e c i p i t a t i o n rate in general circulation models. Six papers were p r e s e n t e d in t h e geophysical fluid d y n a m i c s session; in addition, t h e last p a p e r in t h e ocean session w o u l d m o r e appropri­ ately have b e e n i n c l u d e d in this ses­ sion and will be discussed h e r e .

J.S. Turner surveyed his experi­ m e n t s on double-diffusive convection in which h e used salt and sugar solu­ tions; he s h o w e d a m o t i o n picture of some new e x p e r i m e n t s in w h i c h t h e effects of h o r i z o n t a l inhomogeneities were studied. S.M. T h o m p s o n p r e s e n t e d a t h e o ­ retical model for t u r b u l e n t entrainm e n t based o n t h e i n t e r a c t i o n of a vortex ring w i t h a rigid plane in which t h e bursting of t h e v o r t e x ring when it hits t h e plane is explained as a pressure effect. In a d d i t i o n t o pre­ senting a c o m p u t e r movie he also performed a vivid d e m o n s t r a t i o n of this effect using smoke rings. R . A . D e n t o n presented results from his e x p e r i m e n t s o n e n t r a i n m e n t at a stable interface above a convec­ tive layer. T h e rate of rise of t h e in­ terface was f o u n d t o be i n d e p e n d e n t of t h e d e p t h of t h e convective layer in agreement with H o w a r d ' s ( 1 9 6 4 ) t h e o r y of convection at large R a y leigh n u m b e r . This paper evoked t h e most lively discussion of any at t h e symposium, mainly over t h e appli­ cability of H o w a r d ' s t h e o r y , w i t h t h e pros perhaps coming out o n t o p . A . D . M c E w a n and G.W. Paltridge described experiments o n a radiatively heated, turbid w a t e r layer t h a t was used t o m o d e l radiative cooling at t h e t o p of a stratiform cloud. B.R. M o r t o n reviewed results of field work in t h e a t m o s p h e r e a n d of laboratory e x p e r i m e n t s o n b u o y a n t t u r b u l e n t convection at very large R a y l e i g h n u m b e r s and concluded that t w o distinct scales of m o t i o n exist: a small scale typical of t h e tur­ bulent eddies a n d a large scale typical of t h e b u o y a n t p l u m e . J.M. Richards presented t h e results of an experi­ mental and numerical s t u d y of con­ vection and diffusion w i t h i n puffs. J.A. Whitehead showed some very nice movies of Rayleigh-Taylor insta­ bility e x p e r i m e n t s with very viscous fluids. These showed t h a t , w h e n t h e rising fluid is m o r e viscous t h a n t h e u p p e r fluid, it rises in c o n t i n u o u s columns from t h e lower layer, b u t w h e n t h e rising fluid is less viscous, it rises in blobs disconnected from t h e lower layer. F o u r papers on ocean convection w e r e presented. J.C. Gascard re­ viewed s o m e new results from the continuing s t u d y of deep water for­

m a t i o n in t h e n o r t h w e s t Mediter­ r a n e a n Sea. F r o m current m e t e r m e a s u r e m e n t s he s h o w e d t h a t in t h e winter, stability waves may trigger free c o n v e c t i o n t h a t results in deep water f o r m a t i o n . P.C. Manins p r e s e n t e d a numerical p l u m e m o d e l with application t o t h e circulation of t h e R e d Sea, w h i c h evoked m u c h discussion a b o u t t h e high velocities and low e n t r a i n m e n t c o n s t a n t of t h e m o d e l . T . D . F o s t e r p r e s e n t e d a numerical m o d e l of t h e u p p e r A r c t i c O c e a n w h i c h he h o p e s will help t o predict sea ice g r o w t h . P . D . Killworth de­ scribed t w o c o m p l e m e n t a r y n u m e r ­ ical m o d e l s for t h e f o r m a t i o n of A n t a r c t i c B o t t o m Water. T h e first in­ v o k e d wind-forced convection, a n d the s e c o n d invoked upwelling o n t h e shelf. T o g e t h e r t h e t w o models m a y a c c o u n t for s o m e of t h e major fac­ tors t h a t influence t h e f o r m a t i o n process. Overall, I feel t h a t t h e S y m p o s i u m on D e e p Convection was a w o r t h ­ while a t t e m p t to p r o m o t e exchange of ideas b e t w e e n fluid dynamicists, meteorologists, a n d o c e a n o g r a p h e r s . It is h o p e d that a similar s y m p o s i u m can b e arranged again in t h e f u t u r e . T h e o d o r e D. F o s t e r Scripps I n s t i t u t i o n of O c e a n o g r a p h y La Jolla, California 9 2 0 3 7

IAMAP Plenary Session T h e closing session of t h e special a s s e m b l y in M e l b o u r n e was t h e I A M A P Plenary Session. President S i g m u n d Fritz presided, with Secre­ tary Warren L. G o d s o n assisting. T h e chief m a t t e r s of business were as fol­ lows. 1. T h e I n t e r n a t i o n a l U n i o n of G e o d e s y and G e o p h y s i c s ( I U G G ) G e n e r a l A s s e m b l y in G r e n o b l e , F r a n c e , August 24—September 16, 1 9 7 5 : A t e n t a t i v e list of s y m p o s i u m s was p r e s e n t e d . A large fraction of t h e m are directly c o n c e r n e d w i t h m e t e o r o l o g y or are being cosponsored b y m e t e o r o l o g y . It promises t o be an excellent m e e t i n g . 2. Change of by-laws: It was v o t e d o n and accepted t h a t t h e I A M A P by-laws be a m e n d e d t o m a k e

it possible t o pass o n m a t t e r s relating t o f o r t h c o m i n g meetings at a special assembly. 3. L o c a t i o n of t h e n e x t IAMAP Special A s s e m b l y : With t h e above change in t h e by-laws, it was possible t o consider t h e invitation f r o m t h e United States t o h o l d t h e 1977 IAMAP Special A s s e m b l y t h e r e . (It was n o t e d t h a t the I n t e r n a t i o n a l Association of G e o m a g n e t i s m a n d A e r o n o m y [ I A G A ] had b e e n issued a similar invitation and h a d ac­ cepted.) T h e invitation t o I A M A P was v o t e d o n a n d a c c e p t e d unani­ m o u s l y . T h e meeting will b e held jointly with IAGA. 4. I A M A P / I A G A J o i n t C o m m i s ­ sion: T h e p r o p o s a l t o create a j o i n t

IAGA

Division One Organizational Plans

commission w i t h I A G A t o w o r k o u t such p r o b l e m s as overlapping inter­ ests in t h e u p p e r a t m o s p h e r e was discussed, b u t n o c o n c l u s i o n was r e a c h e d . T h e p r o p o s a l was set aside u n t i l t h e existing c o m m i s s i o n s of IAMAP have h a d an o p p o r t u n i t y t o consider it and u n t i l p r o p e r t e r m s of reference for t h e n e w j o i n t c o m m i s ­ sion can be drafted. 5. R e o r g a n i z a t i o n of I A M A P : T h e reorganization is still in t h e p r o p o s a l stage a n d is still being con­ sidered b y an ad h o c w o r k i n g g r o u p of commission p r e s i d e n t s . In essence, IAMAP would have a n e w n a m e I n t e r n a t i o n a l Association for A t m o ­ spheric Science ( I A A S ) - a n d w o u l d

I

N J a n u a r y 1974 t h e I n t e r n a t i o n a l Association of G e o m a g n e t i s m a n d A e r o n o m y was reorganized i n t o five divisions, each t o c o n c e r n itself w i t h a specific field of research: (1) inter­ nal magnetic fields; (2) a e r o n o m i c p h e n o m e n a ; (3) m a g n e t o s p h e r i c p h e ­ n o m e n a ; (4) solar w i n d / i n t e r p l a n e t a r y magnetic field; and (5) observa­ tories, i n s t r u m e n t s , indices, and d a t a . O n t h e basis of g r o u n d w o r k laid at its first divisional m e e t i n g , t h e executive c o m m i t t e e of division 1 is submitting t o t h e division m e m b e r ­ ship its proposals for an organiza­ tional structure t h a t will be r e s p o n ­ s i v e t o t h e o b j e c t i v e s of t h e association as well as t o t h e n e e d s of those working in t h e research area assigned t o t h e division. A list of suggested subject areas for w o r k i n g groups is included. M e m b e r s are ur­ gently requested t o r e s p o n d w i t h their c o m m e n t s a n d suggestions t o the committee. As defined in t h e proposals, t h e scope of division 1 is t o include areas of research pertaining t o t h e i n t e r n a l magnetic fields a n d t o electromag­ netic induction in t h e e a r t h a n d planets. This includes studies of r o c k m a g n e t i s m , lithospheric anomalies, and t h e past history of t h e geomag­ netic field from a r c h e o m a g n e t i s m . Emphasis will be o n t h e use of t h e data t o describe t h e physics of t h e

have f o u r divisions, relating to atmo­ spheric c h e m i s t r y , dynamics, physics and a p p l i e d m e t e o r o l o g y . A report on t h e p r o p o s a l will be prepared prior t o t h e 1975 IUGG General A s s e m b l y so t h a t national commit­ tees c a n decide o n their votes. 6. O z o n e , R a d i a t i o n , and Atmo­ spheric C h e m i s t r y a n d Radioactivity C o m m i s s i o n s : T h e s e t h r e e commis­ sions will be m e e t i n g individually and j o i n t l y in t h e s u m m e r of 1976 near Munich. 7. R e p o r t o n t h e IAMAP/IAPSO Special A s s e m b l i e s : A total of 596 (of w h o m 3 6 1 c a m e from abroad) a t t e n d e d t h e meetings in Melbourne. C o u n t r i e s r e p r e s e n t e d totalled 32.

d e v e l o p m e n t of t h e e a r t h and other p l a n e t a r y b o d i e s as well as current processes. S u b j e c t s p r o p o s e d for working g r o u p s i n c l u d e analysis of the geo­ magnetic field and secular variations, w i t h a special c o m m i t t e e for refer­ ence fields; t h e o r y of t h e main field and secular variations; electromag­ netic i n d u c t i o n a n d electrical con­ ductivity in t h e e a r t h and moon; magnetic a n o m a l i e s , oceanic and on l a n d ; p a l e o m a g n e t i s m (paleomagn e t i s m / t e c t o n i c relations and pal e o / a r c h e o secular variation; and rock m a g n e t i s m . It was also suggested that i n t e r d i v i s i o n a l or inter association groups b e organized for research in m a g n e t i c stratigraphy, quiet mag­ netic v a r i a t i o n s (internal/external re­ lations), a n d h i s t o r y . Division 1 m e m b e r s are asked for an i m m e d i a t e response t o t h e organi­ zational p r o p o s a l s , including indica­ tion of t h e i r interests according to w o r k i n g g r o u p . T h e aim is to give f i n a l f o r m t o t h e organizational s t r u c t u r e b e f o r e t h e S i x t e e n t h Gen­ eral A s s e m b l y of t h e International U n i o n of G e o d e s y a n d Geophysics in G r e n o b l e , F r a n c e , August 2 4 S e p t e m b e r 6, 1 9 7 5 . R e s p o n s e s t o t h e proposals should be d i r e c t e d t o J.C. Cain, Chairman, I A G A Division 1, C o d e 9 2 2 , Greenbelt, Md. 2 0 7 7 1 .