The estimation of solar radiation under cloudless skies with atmospheric dust

Observations of global radiation received in a small catchment in Yorkshire were analysed for clear sky conditions and an empirical relationship of the form Q = 1380 sin θ( a + b sin θ) W m −2 Found, between incoming solar radiation Q and the solar elevation θ, where a and b are constants. The constants differ markedly from those obtained in a similar analysis of data from eastern Atlantic weather ships, suggesting that the radiation, under cloudless skies, over inland Britain, is only about 60% of that received under cloudless skies over the eastern Atlantic.