Effects of Spatial Sampling of Satellite Data on Derived Surface Solar Irradiance

Abstract

The effect of different spatial sampling of satellite observations on retrieved surface solar irradiance (SW down arrow ) is studied. The results indicate that sampled (8-km resolution) and areally averaged (50-km resolution) visible brightness are highly correlated; the correlation has a regional, seasonal, and diurnal dependence. Using the two different resolutions of satellite observations, SW down arrow was computed for a whole annual cycle. On the average, the results differed by about 8%-9%. Therefore, to validate satellite methods against ground truth to an accuracy which exceeds 8%-9% of the mean, attention should be given to the type of satellite data and ground truth used in the validation process. The scales selected for investigation are of interest to the International Satellite Cloud Climatology Project (ISCCP) B3 sampling. [Journal Article; 45 Refs]