A SPACE-TIME STOCHASTIC CLIMATOLOGICAL APPROACH TO DAILY GLOBAL SOLAR-RADIATION

A stochastic climatological model is presented to describe the space-t ime behavior of daily global solar radiation measured by pyranometers. Due to the difficulty of describing daily global radiation by common probability distributions, a nonparametric technique, the Abramson ker nel estimator, is used. The space-time climatological model of daily g lobal radiation consists of a transformed multivariate autoregressive (AR) process conditioned on large-scale atmospheric circulation patter ns. The transformation is necessary to establish a relationship betwee n the probability distribution of global radiation and a normal variab le used in the AR model. In order to check the stochastic model a simu lation study was performed for 7 locations in Nebraska, USA. Although a split sampling approach could not be used due to the relatively smal l sample size the simulated probability distributions reproduced the e mpirical distributions quite correctly. Also, the space-time dependenc y was maintained. The methodology may be a useful tool to estimate loc al/regional radiation under climate change.