Global Energy And Water Cycles

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

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.

The Global Energy and Water Cycle Experiment (GEWEX) Panel of the National Research Council (NRC) was tasked by the U.S. Global Change Research Program (USGCRP) to provide a rapid and succinct assessment to relevant agencies on the general merit of the GEWEX America Prediction Project (GAPP), as well as the Coordinated Enhanced Observing Period (CEOP). In addition, the panel was asked to provide guidance to the agencies on the relationships between the agencies' newly proposed hydrologic research activities, GAPP, and CEOP. Providing this guidance is critical, in part, because the federal agencies tend to have somewhat differing priorities across the wide span of GEWEX activities.

Water is the most effective agent in the climate system to modulate energy transfer by radiative processes, through its exchanges of latent heat and within cascades of chemical processes. It is the source of all life on earth, and once convective clouds are formed, it enables large vertical transports of momentum, heat and various atmospheric constituents up to levels above the tropical tropopause. Water triggers very complex processes at the earth's continental surfaces and within the oceans. At last, water in its gaseous phase is the most important greenhouse-gas! Numerical modelling and measurements of the state of the present climate system needs a very thorough understanding of all these processes and their various interactions and forcings. This is a prerequisite for more substantial forecasts of future states in all scales of time, from days to centuries. Therefore, the management of the World Climate Research Programme established in 1988 the new programme GEWEX (Global Energy and Water Cycle Experiment). GEWEX is specifically defined to determine the energy and water transports in the fast components of the climate system with the presently available modelling and measurement means and to provide new capabilities for the future. Research in GEWEX must further develop methods to determine the influence of climatic anomalies on available water resources.

The Global Energy and Water Cycle Experiment (GEWEX) Panel of the National Research Council (NRC) was tasked by the U.S. Global Change Research Program (USGCRP) to provide a rapid and succinct assessment to relevant agencies on the general merit of the GEWEX America Prediction Project (GAPP), as well as the Coordinated Enhanced Observing Period (CEOP). In addition, the panel was asked to provide guidance to the agencies on the relationships between the agencies' newly proposed hydrologic research activities, GAPP, and CEOP. Providing this guidance is critical, in part, because the federal agencies tend to have somewhat differing priorities across the wide span of GEWEX activities.