HR: 16:20h
AN: C42C-02    [PDF]
TI: Comparing simulated and measured sensible and latent heat fluxes over snow
AU: * Marks, D
EM: danny@nwrc.ars.usda.gov
AF: Northwest Watershed Research Center, USDA-ARS, 800 Park Blvd Suite 105, Boise, ID 83712-7742 United States
AU: Winstral, A
EM: awinstra@nwrc.ars.usda.gov
AF: Northwest Watershed Research Center, USDA-ARS, 800 Park Blvd Suite 105, Boise, ID 83712-7742 United States
AU: Elder, K
EM: keldere@fs.fed.us
AF: Rocky Mountain Research Station, USDA Forest Service, 240 W. Prospect Rd, Fort Collins, CO 80526 United States
AU: Pomeroy, J
EM: pomeroy@usask.ca
AF: University of Saskatchewan, 9 Campus Drive, Saskatoon, Sas S7N 5A5 Canada
AB: Verifying simulated sensible and latent heat fluxes over snow has seldom been attempted because of the difficulty in direct measurement. Recent development of more robust eddy correlation (EC) systems allowed us to directly measure fluxes of heat and water vapor over snow during the 2003 NASA Cold Lands Processes Experiment. Measurements were made from February through melt-out of the snowcover in mid-June, 2003, at the Local Snow Observation Site (LSOS) in the Fraser Experimental Forest in Colorado. The measurement system was located in an open stand of pines, along with two additional meteorological measurement systems which monitored radiation, temperature, wind, humidity, snow and soil temperature, and snow depth. Precipitation was measured at the near-by USFS climate monitoring station. Th ough the EC system was operated continuously for nearly 5 months, reliable data are available only during relatively clear periods between storms. The point model SNOBAL was used to simulate the snowcover energy and mass balance over this same period of time. Measured fluxes follow the same trends as simulated with sensible heat flux being toward the snow and latent heat flux away from the snow. However, the magnitude of the simulated fluxes were less than those measured by the EC system. This measurement effort shows the need to better tune the EC system to conditions over snow, particularly during storms and condensing conditions. It also indicates that snowcover energy balance simulations are sensitive to wind measurement errors under low-wind conditions such as that found below a forest canopy.
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2003 Fall Meeting