Efforts to understand climate variability and predict future climate change have highlighted many aspects of the hydrologic cycle and the exchange of energy and water at the atmosphere-surface interface as areas of critically needed study. The very nature of weather and climate demands that an international perspective and a comprehensive research approach be applied to understand these important issues. In response to this need, the international partners of the World Climate Research Program developed GEWEX (Global Energy and Water Experiment) as a major focus of international study. As the first of five continental-scale experiments, the GEWEX Continental Scale International Project (GCIP) was established to quantitatively assess the hydrologic cycle and energy fluxes of the Mississippi River basin. GCIP focuses on understanding the annual, interannual, and spatial variability of hydrology and climate within the Mississippi River basin; the development and evaluation of regional coupled hydrologic/atmospheric models; the development of data assimilation schemes; and the development of accessible, comprehensive databases. Improved water resource management on seasonal to interannual time scales is also a key GCIP goal. This book reviews the GCIP program, describes progress to date, and explores promising opportunities for future progress.

A comprehensive treatment of models and processes related to water fluxes for meteorologists, hydrologists and oceanographers.

The high latitudes of the Arctic and Antarctic, together with some mountainous areas with glaciers and long-lasting snow, are sometimes called the cryosphere-defined as that portion of the planet where water is perennially or seasonally frozen as sea ice, snow cover, permafrost, ice sheets, and glaciers. Variations in the extent and characteristics of surface ice and snow in the high latitudes are of fundamental importance to global climate because of the amount of the sun's radiation that is reflected from these often white surfaces. Thus, the cryosphere is an important frontier for scientists seeking to understand past climate events, current weather, and climate variability. Obtaining the data necessary for such research requires the capability to observe and measure a variety of characteristics and processes exhibited by major ice sheets and large-scale patterns of snow and sea ice extent, and much of these data are gathered using satellites. As part of its efforts to better support the researchers studying the cryosphere and climate, the National Aeronautics and Space Administration (NASA)-using sophisticated satellite technology-measures a range of variables from atmospheric temperature, cloud properties, and aerosol concentration to ice sheet elevation, snow cover on land, and ocean salinity. These raw data are compiled and processed into products, or data sets, useful to scientists. These so-called "polar geophysical data sets" can then be studied and interpreted to answer questions related to atmosphere and climate, ice sheets, terrestrial systems, sea ice, ocean processes, and many other phenomena in the cryosphere. The goal of this report is to provide a brief review of the strategy, scope, and quality of existing polar geophysical data sets and help NASA find ways to make these products and future polar data sets more useful to researchers, especially those working on the global change questions that lie at the heart of NASA's Earth Science Enterprise.