Preliminary modeling of the time variation of the monthly means of some climatic parameters in some localities of chad

In this paper we investigate the best fitting formulas of the time variation of the monthly means of some climatic parameters in the localities of Moundou, N’djaména, Pala and Sarh in the southern part of Chad. We have obtained that the insolation can be fitted by a quadratic function while the minimal, normal and maximal temperatures, minimal and maximal relative humidity of the air can be fitted by cubic functions. The degree of fitness of the empirical formulas generated by their corresponding models were at most one order less the empirical and theoretical values of the considered parameter, indicating that they can be used in operative works to fill missed data in chronological series.