The empirical relation between sunshine and radiation and its use in estimating evaporation in North East England



The relation between the duration of sunshine hours and radiation derived from ten years of daily records at Eskdalemuir and Cawood differs significantly from formulae in general use with the Penman formula. When used in the Penman formula with meteorological data from North East England evaporation estimates were more satisfactory than those based on commonly used formulae. While winter months showed different relations between sunshine and radiation their use in estimating evaporation made no significant difference on cumulative evaporation over a year. The regression R/RA = 0.1894-0.624(n/N) derived from Eskdalemuir is satisfactory for use in North East England.