Variability in Space of Solar Radiation

Summary

Data from six out of 19 existing stations measuring global radiation have been prepared for a statistical analysis. Series of simultaneous measurements from the period January 1980 to August 1981 have been apt to an automatic error-finding procedure and have been corrected due to systematic fluctuations over time. The statistical structures in data have been investigated at the aim of revealing properties which can be exploited especially for the study of spatial correlations. It has become clear that traditional calculations of measures of correlation do not to a satisfactory degree compensate for certain variance structures in data. In fact, a logtransformation of data is shown to be necessary. The report outlines the structure of a statistical model which will be used for further analyses. It is an important characteristic of the model that it specifies the (logaritmic) mean values as composed by a site-specific parameter and a timespecific parameter, hence allowing the variation in global radiation over time to be systematic rather than stochastic. All correlations are defined in the light of this model.