Calibration and sensitivity analysis of a spatially-distributed solar radiation model

SRAD, a spatially-distributed solar radiation model, was applied to a Canadian boreal forest environment in north-western Ontario. SRAD is grid based, and factors in both topo- and meso-scaled processes using a digital elevation model (DEM) and local monthly atmospheric parameters as inputs. SRAD generates estimates of incident, outgoing, and net irradiance, as well as surface and air temperatures for each point in the DEM, over any time period ranging from one day to one year. Cloudiness and other atmospheric conditions are factored into the shortwave irradiance estimates. From the DEM, the terrain effects of slope angle, aspect, and topographic shading are calculated and used to modify the estimates of shortwave irradiance. The SRAD-generated irradiance estimates for the study region were found to be consistent with irradiance data from other sources. Estimates of irradiance were most sensitive to the parameters of sunshine fraction and cloudiness. Radiation estimates were generated and compared using b...