Experiment to characterize tropical cloud systems

Eos,Vol. 86, No. 31, 2 August 2005 ern Regional Climate Center of the Desert Re­ s e a r c h Institute; and the San Francisco Water and Power Administration is appreciated.

Merced River

References Brown, J. C, and C. M. Skau (1975), Chemical com­ position of snow in the east central Sierra Nevada, Coop. Rep. Sen Publ. AG-], 14 pp., Cent, for Water Resour. Res., Desert Res. Inst., Reno, Nev. Cayan, D. R., and D. H. Peterson (1989), The influ­ ence of North Pacific atmospheric circulation on streamflow in the west, in Aspects of Climate Variability in the Pacific and the Western Ameri­ cas, Geophys. Monogr. Ser, vol. 55, edited by D. H. Peterson, pp. 375-397, AGU, Washington, D.C. Cayan, D. R., M. D. Dettinger, K. T. Redmond, G. J. McCabe, N. Knowles, and D. H. Peterson (2003), The transboundary setting of California's water and hydropower systems-linkages between the Sierra Nevada, Columbia River, and Colorado River hydroclimates, in Climate and WaterTransboundary Challenges in the Americas, Adv. Global Change Res. Ser., vol. 16, edited by H. F. Diaz and B. J. Woodhouse, chap. 11, pp. 237-262, Springer, New York. Clow, D. W, J. O. Sickman, R. G. Striegl, D. P. Krabbenhoft, J. G. Elliott, M. Dornblaser, D. A. Roth, and D. H. Campbell (2003), Changes in the chemistry of lakes and precipitation in highelevation national parks in the western United States, 1985-1999, Water Resour. Res., 39(6), 1171, doi:10.1029/2002WR001533. DiLeo, J., et al. (2003), Notebook of hydroclimatology: Sites/activities—Yosemite National Park, 34 pp., U.S. Geol. Surv. (Available at http://sfbay. wr.usgs.gov/access/HydroClim/SiteBook.pdf) Peterson, D., R. Smith, S. Hager, K. Huber, M. Dettinger, and J. DiLeo (2004), Alpine hydroclimatology: Exploring the mystery of salinity change in portions of the Stanislaus and Merced Rivers, 24 pp., U.S. Geol. Surv. (Available at http://sfbay.wr.usgs.gov/ acess/HydroClim/HydroclimTutorial.pdf) Author

Happy Isles, YNP

-

Gross Primary Productivity

CM

O Jan Feb Mar Apr May Jun

Fig. 3. Merced River discharge at Happy Isles 2002 (warm spring) and 2003 (cool spring) and MODIS-derived gross primary production for the same years. Original color image appears at the back of this volume.

NEWS Experiment To Characterize Tropical Cloud Systems PAGES 2 8 5 - 2 8 6 A major experiment to study tropical convective cloud systems and their impacts will take place around Darwin, northern Australia, in January and February 2006.The Tropical Warm Pool International Cloud Experiment (TWP-ICE) aims to study cloud systems and their radiative, chemical, and moisture budget impacts from the initial convection through to the decaying, convectively generated cirrus. This broad aim is being addressed by a dense observational network that includes two sites equipped with cloud radar and lidar,a polarimetric (dual-polarization) weather radar

Jul Aug Sep Oct Nov Dec

Months

Information

David Peterson, Richard Smith (retired), and Stephen Hager, U.S.Geological Survey, Menlo Park, Calif.; Jeffrey Hicke, Colorado State University, Fort Collins; Michael Dettinger, U.S. Geological Survey, LaJolla, Calif.; and King Huber, U.S. Geological Sur­ vey, Menlo Park, Calif.

2002 2003

and another operational Doppler radar in the area, wind profilers, infrared interferometers, flux stations, lightning interferometers, and oceanographic measurements. Also, an array of five radiosonde sites arranged in a ring with a diameter of about 250 km around Darwin will conduct soundings every three hours for a period of 24 days. In addition, a fleet of aircraft includes highaltitude aircraft for in situ cloud and chemistry sampling,aircraft for remote sensing (cloud radar, lidar, radiometry and infrared interferometry),and an atmospheric boundary layer aircraft (Table 1). Crucial satellite data will also b e gathered.The experiment design

ensures that not only will an outstanding data set for cloud properties b e collected, but also that this data set can b e placed in a synoptic and global context with the radar and satellite coverage, soundings, and numerical weather prediction so that the results gathered here can b e applied globally. Also, the data set should b e ideal for heating, water, and momentum budget studies, i.e., the impact of the convection in the area, and for providing the boundary con­ ditions for modeling activities ranging from climate models to weather prediction, cloud resolving, and single-column models. TWP-ICE is a collaboration of the U.S. Depart­ ment of Energy's (DOE) Atmospheric Radiation Measurement (ARM) Program and the ARMUnmanned Aerospace Vehicle (UAV) Program, NASA centers, the Australian Bureau of Meteorol­ ogy Commonwealth Scientific and Industrial Re­ search Organisation (CSIRO),Airborne Research Australia (ARA),and universities in Australia, Canada, Japan, the United Kingdom, and the United States. Detailed atmospheric measure­ ments will be made through the austral summer,

Eos, Vol. 86, No. 31, 2 August 2005 providing unprecedented coverage through the pre-monsoon and monsoon periods. The timing of the experiment corresponds with the maximum in monsoonal rainfall across northern Australia. However, the large intra-seasonal variability in the region makes it likely that o c e a n i c m o n s o o n systems as well as continental "break" storms will b e sampled. S o m e of the specific s c i e n c e questions that will b e addressed include: • How do the cirrus microphysical char­ acteristics vary with convective intensity and evolve as the clouds age? • How do tropical cirrus clouds affect water and radiation budgets? • What are the microphysical characteristics of thin, high-level cirrus clouds that are ubiqui­ tous in the area? • What controls the diurnal cycle of oceanic convection, and how is this related to the evolu­ tion of the boundary layer structure? A focus of the experiment will b e the valida­ tion of results from ground-based and satellite remote sensing.These include in situ measure­ ment of cirrus cloud microphysics to validate and test the remotely sensed retrievals of cloud characteristics from radar, lidar, and radiometers from the ground and from aircraft. Validation of the NASA CloudSat and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) products also are key experiment goals. Data arising from this experiment will b e made available to the wider community, and could b e a major resource for tropical meteo­ rological research for many years. Programs and centers that will use the data include the

World Climate Research Programme's Global Energy and Water Cycle Experiment Global Cloud System Study and the European Centre for Medium-Range Weather Forecasting. TWP-ICE is collaborating closely with the aircraft experiment organized through the European Union's SCOUT-03 (StratosphericClimate Links with Emphasis on the UTLS) project and the United Kingdom's Natural En­ vironment Research Council (NERC) ACTIVE (Aerosol and Chemical Transport in Tropical Convection) projects in November and Decem­ ber 2005.These projects will benefit from the outstanding permanent observing network in the area (one of the best anywhere in the tropics). The projects also will use a number of research aircraft, s o m e of which will also b e available in TWP-ICE. Additional s c i e n c e questions for this component of the austral summer's activities that are combined with TWP-ICE include the following: • What is, and what controls, the chemical com­ position of the tropical tropopause layer (TIL)? • How fast are short-lived c h e m i c a l species (e.g.,bromine c o m p o u n d s ) transported into, and through, the TTL? What is their likely im­ pact on the ozone budget? • How do thunderstorms transport aerosols and c h e m i c a l species into the TTL? • What is the relative importance of deep convection and large-scale advection in deter­ mining the composition of the TTL? The studies made in TWP-ICE and related campaigns offer an unprecedented opportu­ nity to address the relative roles and impacts of intense continental-type storms and the

MEETINGS Water Supply Planning in the Lake Michigan Region PAGE 2 8 7 Standing in Chicago, Illinois, and gazing across the vastness of Lake Michigan, it is hard to imagine that communities in the surround­ ing region could b e c o n c e r n e d about running short of water. However, international treaties, U.S. Supreme Court decrees, and interstate agreements restrict diversions of water from the Great Lakes in an effort to maintain lake levels.This forces the region to use alternative sources of water to serve the rapidly growing population. Local governments in the southern Lake Michigan region, and likely elsewhere in the Lake Michigan region, need to acquire and integrate data and information regarding the region's water supply into planning processes. In response to the clear potential for water supply shortages, the Northeastern Illinois

Planning Commission (NIPC) and the Illinois State Water Survey (ISWS) organized a recent conference entitled "Straddling the Divide" to foster a dialogue between engineers, planners, scientists, politicians, and other stakeholders who have a c o m m o n interest in maintaining the availability of water for the region's communities.Among the more than 200 confer­ e n c e attendees were representatives from mu­ nicipalities, councils of government, regional planning commissions, state and federal agen­ cies, water resources consulting firms, and universities. According to census-based forecasts, future growth near Lake Michigan in Wisconsin, Illinois, and Indiana will present distinct challenges for planners in the region.The population of the re­ gion surrounding Lake Michigan is expected to grow by 20% by the year 2030. In many instances, population and urban development are increas-

T a b l e 1. TWP-ICE A i r c r a f t and Their Principal Roles Aircraft

Primary

Role/Instruments

DOE Proteus

lidar/in situ microphysics

ARA Egrett

in situ microphysics, aerosols, and chemistry

NERC Dornier

aerosols and chemistry

Twin Otter International

radar/lidar

ARA Dimona

in situ state measurements, fluxes

more widespread but weaker o c e a n i c storms with o n e of the most comprehensive tropical data sets ever collected. More information about the experiments is available online at http://www.bom.gov.au/ bmrc/wefor/research/twpice.htm,http:// science.arm.gov/~mather/darwiniop/, and http://www.ozone-sec.ch.cam.ac.uk/scout_o3/ Darwin/index.htm.

—PETER T. MAY, Bureau of Meteorology Research Centre, Melbourne,Victoria, Australia; JAMES H. MATHER, Pacific Northwest National Laboratory Richland,Wash.; and CHRISTIAN JAKOB, Bureau of Meteorology Research Centre, Melbourne,Victoria, Australia

ing in areas where water is supplied by aquifers and where Lake Michigan water is not available. These trends underscore the need for careful planning to sustain the quantity and quality of groundwater available to meet future demand. NIPC Director of Planning Sam Santell told conference attendees that although the region faces urgent water supply issues, there is an opportunity to address them now rather than wait for a bigger crisis. He said addressing the problem requires cooperation at the municipal, county, regional, and interstate levels. One example of this multi-level, inter-re­ gional planning is the U.S. Environmental Protection Agency's (EPA) 2004 management plan for Lake Michigan.lt represents an agree­ ment among four states, 10 Indian tribes, and six federal agencies on the sustainable use of the lake. The conference helped to provide a critical follow-up step to the EPA planning process: en­ gaging stakeholders across administrative and disciplinary divides that often hinder planning and management. The conference consisted of over 20 invited talks summarizing scientific, engineering, and policy issues regarding the region's water resources. Greg Ellis, formerly of the Edwards Aquifer Authority in Texas, and Pat Stevens of the Atlanta Regional Commission in Georgia discussed water supply planning and manage-