Submitted to: Trans American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 12/11/1998
Publication Date: N/A
Technical Abstract: A key component of the SGP experimental plan was to measure surface energy fluxes over representative vegetation cover types existing in the study area. One of the main sites chosen for such observations was located in the USDA-ARS Grazinglands Research facility in El Reno, Oklahoma. The surface energy balance was estimated for pasture, rangeland, and harvested/ /disced winter wheat fields. Fluxes were estimated by Bowen ratio and eddy correlation systems. Rainfall occurred frequently throughout the observation period; however, there were several drydown periods providing a dynamic range in near-surface moisture conditions. Changes in near-surface moisture had a dramatic impact on the harvested wheat fields where the energy partitioning, expressed as the ratio of sensible to latent heat flux (i.e., Bowen ratio, Bo), varied by an order of magnitude. All other sites showed smaller changes in Bo because of adequate moisture in the root zone to accommodate increases in atmospheric demand. Factors influencing differences in surface fluxes and for the various cover types will be discussed.