Alterations in land surface-atmosphere processes resulting from the 1988 Greater Yellowstone Area fires

During the late summer of 1988, wildland fires in Yellowstone National Park and the surrounding Greater Yellowstone Area (GYA) burned approximately 570,000 ha. The dramatic alteration in land cover resulting from these fires coupled with the availability of surface and satellite data necessary for modeling land surface-atmosphere processes provides an ideal opportunity to study the effects of fire-induced vegetation changes on surface energy budget variables and soil moisture.; Meteorological observations for the 10-year period 1984 to 1993 have been collected from 178 stations within the GYA, quality assured, and spatially and temporally interpolated to produce gridded data suitable for model input. These data comprise 8-km resolution hourly values of seven meteorological variables: near-surface air temperature, relative humidity, precipitation, wind speed, atmospheric pressure, and downwelling solar and longwave radiation.; New algorithms for modeling of snow and frozen soil have been implemented in the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS) model. These added capabilities, necessary for using the SHEELS model in the GYA, allow for the hydrologic, thermal, and albedo effects of snow cover and frozen soil to be realized in model output.; The SHEELS model was then used to examine surface energy budget and soil moisture variables before and after the 1988 fires. Four datasets of these variables were produced for each of three regions within the GYA: a burn area consisting of fire-affected regions, an area upwind of the burn area, and an area downwind from the burn area. The four datasets provide a basis for differentiation among possible causes of any observed alterations in surface energy budget or soil moisture variables and result from varying the vegetation or meteorological model forcing.; Substantial alterations of the latent and sensible heat fluxes were found to result from the removal of vegetation by the 1988 fires. Specifically, latent heat flux was decreased and sensible heat flux increased in the burn area. Furthermore, these effects also were seen downwind of the burn area, indicating that regional climate may have been affected by the fires. Soil moisture was not substantially affected by the fire-induced vegetation changes, however.