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NCAR INITIATIVES

>WATER CYCLES ACROSS SCALES

OBJECTIVE

The main goal of the NCAR Water Cycle Across Scales initiative is to improve predictions of the water cycle in weather and climate models. This goal will be achieved through increased understanding of processes within the water cycle, thereby enabling improvements to convective, land surface, and microphysical parameterizations. Phase I (FY02-05) has been on the summer water cycle over the Continental U.S. using data from the IHOP_2002 field program, NCAR/NCEP and ECMWF ERA-40 re-analysis data, and modeling studies. Four focus areas have been defined, as shown in the figure below. Specific tasks for each focus area are also listed, as well as the interactions among tasks. A particular area of focus will be utilizing the diurnal cycle of water cycle processes, particularly precipitation over the Continental U.S. as it provides a means of systematically examining, testing and improving model predictions.

Steering committee: Roy Rasmussen (chairman), Fei Chen, Jim Hack, Mitch Moncrieff, David Parsons, Kevin Trenberth, Tom Warner, and Jim Wilson.