On correlating the relative sunshine duration with the state of the sky

Abstract

The state of the sky defined in terms of the cloud cover has been correlated with bright sunshine duration using data from five meteorological stations in Bangladesh. The r.m.s. errors of computed sunshine duration using the correlation are 2 to 5% for these stations. The correlation has been tested for three stations which have been found to give satisfactory estimates of sunshine duration from the cloud cover. Hence, it is expected that for stations which do not have sunshine recorders the state of the sky should give good predictions of sunshine duration and hence global radiation.