Empirical Relationships Between Global and Diffuse Radiation and Sunshine Duration in Chad: Polynomial Regression Approach

Chad, in regards to its geographical position is considered as one of the countries world that receives an important annual solar radiation over entire territory. The average sunshine duration about 10 hours North, 8 Center and 7 South. This can be used quantify whole territory evaluate potential. In this paper, some new correlations between have proposed four cities (Abeche, Bitkine, Mongo Ndjamena) located Sahelian climate order tools for quantifying all components radiation. polynomial regression model approach their parameters are estimated by ordinary least squares method. A statistical evaluation was carried out compare different obtained. results show third most appropriate empirical relationship global, diffuse relative each cities. Considering long dry seasons characterized high temperatures region, consideration temperature variable functional form could improve quality accuracy models estimation.