EVALUATION OF THE ATMOSPHERIC WATER CYCLE IN ERA-40 USING OBSERVATIONALLY-CONSTRAINED LAND MODEL RESULTS

Quantifying the various storage and flux compo-nents of the global water and energy cycle and determining their variability and changes, and their causes, are a central goal of GEWEX and other global projects. Our quantitative knowledge about these components is still fairly limited because of a lack of reliable data for global clouds, precipitation, evaporation, terrestrial runoff, and other fields (Trenberth et al., 2006). Improved long-term obser-vations and global analyses of these fields are critical for studying the global climate and its future changes. However, most fields have been studied in isolation rather than in the framework of the entire cycle. A synthesis of observed atmospheric data through glo-bal analyses of multi-variate data can potentiall