Estimating global radiation on sloping surfaces

Abstract

A recent article by Radcliffe & Lefever (1981) included global radiation estimates for sloping surfaces calculated from horizontal surface measurements. The estimation method used (McAneney Noble 1976) was derived from direct radiation considerations only. By not taking diffuse radiation into account this method may not provide good estimates of global radiation. This will be particularly so in the winter months when global radiation on northern facing slopes will be over-estimated and on southern facing slopes will be under-estimated.