§16§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 En §16§ergy 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. §04§1 Atmospheric Energetics and the Water Cycle.- 2 Aspects of Large Scale Modelling.- 3 Radiation-Cloud-Climate Interaction.- 4 Convective and Large-Scale Cloud Processes in GCMS.- 5 Satellite Observations of Radiation and Clouds to Diagnose Energy Exchanges in the Climate: Part I.- 5 Satellite Observations of Radiation and Clouds to Diagnose Energy Exchanges in the Climate: Part II.- 7 Observation and Analysis of Global Rainfall.- 8 Data Assimilation Problems.- 9 Forcing the Ocean by Heat and Freshwater Fluxes.- 10 Modelling of Oceans Circulation.- 11 Observations of Air Sea Fluxes.- 12 Sea-Ice Interactions in Polar Regions.- 13 The Soil-Vegetation-Atmosphere Interface.- 14 Observing and Modelling the Planetary Boundary Layer.- 15 The Terrestrial Hydrological Cycle.- A Databases for Gewex Research.- B Poster-Session.
