The distance factor in the relationships between solar radiation and sunshine

✍ Scribed by Baker, Donald G. ;Skaggs, R. H.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1984
• Weight: 640 KB
• Volume: 4
• Category: Article
• ISSN: 2314-6214
• DOI: 10.1002/joc.3370040203

✦ Synopsis

The effect that distance ( d ) has upon the correlation coefficient (r) obtained between paired radiation ( R ) and sunshine (S) stations was determined for the North Central region of the United States. Distances between stations vaned from 0 to 608 km.

In the regression of r against d three features of interest were found. First, the slope of the annual r values with distance is essentially linear from about 60 to 550 km and equals about -0.12/100 km. Secondly, from d = 0 to 60 km, the value of r remains constant at about 0.88, creating a 'zone of indifference' due to inherent differences between radiation and sunshine recording instruments and the insensitivity of the latter. Thirdly, beyond about 550 km the slope appears to reach a constant value, which varies with season but is about r = 0.30 on an annual basis.

Seasonal and geographical differences in the degree of correlation between r and d are noted and discussed briefly.