Solar radiation climate of India

Abstract

This paper presents the essential results of solar radiation measurements made at a network of thirteen stations in India during the last ten years. The basic records are of total integral wavelength global solar radiation and sky radiation on a horizontal surface, and of direct solar radiation and its spectral components, defined by the wavelength intervals λ < 525, 525-630, λ < 630, 525-710 and λ < 710 nm. Values of direct solar radiation at normal incidence and on horizontal and vertical surfaces have also been calculated from continuous records of the global and sky radiation on a horizontal surface at all 13 stations. The spatial and seasonal variations of direct solar radiation, global solar, and sky radiation are discussed. Results are also presented of special direct solar observations made at a few high altitude stations in Kashmir in 1969.