(SGER) BOREAS SSA Precipitation Radar

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9321105 Lettenmier The goal of BOREAS is "to improve our understanding of the interactions between the boreal forest biome and the atmosphere. The experimental design is based on intensive observations during summer, 1994, of two study areas of approximate size 400-600 km2, near the northern and southern limits of the boreal forest biome. The study areas, which are about 600 km apart, are near Thompson, Manitoba, and Nipawin, Saskatchewan. The objectives of this project are to acquire a radar data set for the BOREAS Southern Study Area (SSA) to define the spatial variability of precipitation in the summer of 1994 in 160 km diameter circle centered in the SSA. The precipitation is maximum in mid-summer and is associated with convective storms. Understanding the spatial distribution of summer precipitation, and the associated dynamics of soil moisture, are critical to the goal of BOREAS. Knowledge of the space-time distribution of soil moisture, and related runoff-generation mechanisms that affect evaporative fluxes under conditions of soil limitation, will be essential for studies exploring the interactions of boreal vegetation, trace gas fluxes, and other aspects of land-atmosphere dynamics in northern climates. Upscaling detailed local-scale energy and mass balances, and biophysical studies using remote sensing and modelling is an essential component. Upscaling is important because transport mechanisms occur at the scale of hundreds of km, but the governing processes are largely measure at the field scale. The PI's BOREAS research is funded by NASA and the proposed funding would, in its entirety, go toward the cost of locating, operating, and processing data collected from a C-band precipitation radar. The cost would be shared with the Canadian Atmospheric Environment Service (AES). The proposal should be considered as representative of a general need of the BOREAS community. ***