Abstract

Solar radiation is the primary energy source for all physical and biochemical processes that take place on earth. Energy balances are a key feature of processes such as temperature changes, snow melt, carbon fixation through photosynthesis in plants, evaporation, wind intensity and other biophysical processes. Solar radiation level is sometimes recorded, but generally it needs to be estimated by empirical models based on frequently available meteorological records such as hours of sunshine or temperature. This paper evaluates the behavior of two empirical models based on the difference between maximum and minimum temperatures and compares results with a model based on sunshine hours. This work concludes that empirical models based on temperature have a larger coefficient of determination than the model based on cloud cover for the normal conditions of Chile. These models are easy to use in any location if the parameters are correctly adjusted. In addition, probability distribution functions and confidence intervals for solar radiation estimates using stochastic modeling of temperature differences were calculated. (C) 2000 Published by Elsevier Science B.V. All rights reserved.