Spatial Coherence of Incoming Solar Radiation for the Southern Piedmont

The spatial coherence of incoming solar radiation is examined for a mesoscale network of locations across the Southern Piedmont region of Alabama, Georgia, and South Carolina. Data from the National Climatic Data Center's (NCDC) Solar and Meteorological Surface Observation Network (SAMSON) are used in the analysis for the period 1961-1990. The method involves calculation of the standard deviation of the daily differences in solar radiation receipt for each pair of stations and the determination of a coefficient of variability. These are plotted as a function of distance between station pairs to establish absolute and relative solar radiation spatial variation relationships. In addition to overall annual and decadal analyses, the spatial coherence for different seasons is assessed. Results are compared to similar previous studies in other mesoscale regions, all of which were based on much shorter periods of record.