PROGRAM TITLE: Clouds, Energy and Water (GEWEX) ACTIVITY STREAM: Process Research SCIENCE ELEMENT:Climate and Hydrological Systems DEPARTMENT OF COMMERCE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION DESCRIPTION: Two of the highest scientific priorities in the USGCRP in determining the nature and variability of the Earth's climate system involve understanding the nature of land-atmosphere-ocean water and energy interactions, and the role of clouds. This program encompasses NOAA's primary contribution to the Global Energy and Water Cycle Experiment (GEWEX) of the World Climate Research Program (WCRP), and to related projects of the International Geosphere Biosphere Program (IGBP). The principle thrusts are directed at: -- atmosphere-land surface interactions -- distribution of atmospheric water vapor -- cloud processes, and -- radiative impacts of anthropogenic aerosols Support within each of these thrusts is given to special observing programs, to process and diagnostic studies, and to the development of parameterization techniques that improve the representation of subgrid-scale processes in climate models. Many of these processes operate on very short time-scales, however, our ability to represent them explicitly or implicitly in climate models is critical to successful prediction of climate change on seasonal to decadal and longer time-scales. The mechanisms through which NOAA will implement this program involve promotion and participation in: -- the GEWEX Continental-scale International Project (GCIP), including the role of Lead Agency and sponsorship of the project office; -- the Global Water Vapor Project (GVaP); -- the International Satellite Cloud Climatology Project (ISCCP) and the GEWEX Cloud System Study (GCSS) Project, aerosol climatology and characterization projects of IGBP, and -- the emerging CLIVAR/GOALS project on large-scale influences on seasonal to interannual variability of North American precipitation. STAKEHOLDERS: NOAA will work closely with those USGCRP partners also contributing directly and indirectly to the activities of GEWEX and IGBP, including NASA, DOE, USGS, USDA and NSF. NOAA will also continue to play an active role in national and international planning mechanisms for GEWEX and related programs through its involvement in and support for National Academy, WCRP and IGBP scientific committees and working groups. Particular attention will be given to coordinating studies planned for the continental United States with related programs in Canada and the countries of Central and South America. SHORT-TERM POLICY PAYOFFS: Enhancing measurements of key climate parameters over the Mississippi River Basin and adjacent areas, coupled with work already in process on improving subgrid-scale parameterizations, will lead to a better understanding of the complex hydroclimatology of the Basin. The incorporation of improvements deriving from this increased understanding into predictive models of the climate system will enable greater specificity in seasonal to interannual predictions of regional climate variability. Further, knowledge gained on water and energy processes over the data rich regions of the continental United States can be applied to regions of the earth's surface less well monitored by in situ observing systems; this is the primary rationale behind GCIP. Concurrent advancements in global remote sensing capabilities will lead to improved global models, and to greater confidence in assessments of the regional impacts of global change. PROGRAM CONTACT:Michael Coughlan, Office of Global Programs, 1100 Wayne Avenue, Suite 1225, Silver Spring, MD 20910 (301) 427-2089 X40.