Abstract
Macro-scale hydrological models have been investigated for the purpose of introducing the effect of land surface heterogeneity to the GCM. The shortwave radiation budget, which is one of the most important components, is influenced by the topography as well as the surface albedo. Generally speaking the topographical effect on incident solar radiation is expressed by using inclination and aspect of a slope. This paper evaluates the difference between the insolation receiving rate using only averaged inclination and aspect on the grid scale of a GCM and one by using the variance and co-variance as well as mean values. The difference is related to a area-wise parameter to give the effect of topographical heterogeneity on shortwave radiation budget.
