SPATIAL COHERENCE OF SOLAR-RADIATION FOR REGIONS IN THE CENTRAL AND EASTERN UNITED-STATES

Information from the National Climatic Data Center's Solar and Meteoro logical Surface Observation Network CD-ROM data set is used to study t he spatial coherence of incoming solar radiation for selected regions in the United States for the 30-year period 1961-1990. Networks of nin e sites are analyzed for each of five regions: North Central, Ohio Val ley, New England, East Texas, and Southern Piedmont. The spatial coher ence of solar radiation is examined by calculating the standard deviat ion of daily differences in solar radiation receipt for paired station s and subsequently determining a coefficient of variability. These are plotted as a function of distance between station pairings to establi sh absolute and relative solar radiation spatial-variation relationshi ps. Comparisons are made among the five regions with the Southern Pied mont showing the most spatial coherence and New England generally havi ng the greatest Variation (i.e., greater standard deviation and coeffi cient of Variability values with distance). Interdecade analyses revea l that the relationships are temporally stable, with only slight diffe rences in the three separate decade solar radiation relationships for each region.