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.

This book presents decade-long advances in atmospheric research in the Mackenzie River Basin in northern Canada, which encompasses environments representative of the coldest areas on Earth. Collaborative efforts by a team of about 100 scientists and engineers have yielded knowledge entirely transferable to other high latitude regions in America, Europe and Asia.

Water vapor plays a vital role in shaping weather and climate on Earth. Hence, monitoring water vapor is critical if we are to explain and predict the behavior of the climate system. Unfortunately, measuring and analyzing water vapor on the time and space scales needed for this purpose have proven elusive. Therefore, it is appropriate and timely for the international climate research community, through the Global Energy and Water Cycle Experiment (GEWEX), to focus a project around water vapor. To this end, a GEWEX Global Water Vapor Project (GVaP) has been proposed, and draft Science and Implementation Plans have been developed. As requested by the U.S. Global Change Research Program (USGCRP), the National Research Council's (NRC) GEWEX Panel has reviewed these plans with an eye toward U.S. priorities.