Study of the statistical correlation of the global radiation Case study of Tetuan in northern Morocco

In this paper, we are interested in meteorological data of the global radiation of the city of Tetuan in northern Morocco. Thus, we conducted a comparative study of solar radiation values recorded with those values given by the general mathematical model of Rietveld. Results enabled us to calculate new Rietveld model parameters that fit the best our actual data. We used actual data from a meteorological station and we used a mathematical model to calculate the global solar radiation of Tetuan. We studied also in this paper the best solar radiation minimum that gives the best correlation between the daylight duration ratio and the global solar radiation ratio.