A simulation of topographic solar radiative forcing over a mountainous region using geostationary satellite data

摘要

The radiative forcing effects of topography and clouds were examined for a mountainous region during the rainy season to further our understanding of the relative roles of each in modulating incoming solar energy at the Earth's surface. Solar radiation fields derived from hourly, 8 km GOES observations were used to drive a topographic solar radiation model at 60 m resolution during August 1988, for the Rio Grande River basin in Colorado. Monthly, basinwide mean solar radiative forcing as a percentage of average, clear-sky insolation was -37.3% for clouds and +10.2% for topography. The overall positive monthly topographic forcing (+10.2%) resulted from positive elevation effects (+18.6%); these outweighed the negative forcings (-8.4%) caused by terrain. These results suggested that topography must be considered for clear, cloudy, and partly cloudy conditions in mountainous regions, even at coarse temporal and spatial scales.