Analysis of Rainfall and Temperature over a sub-basin of Lake chad

Abstract

Rainfall and temperature are two climatic variables that are indispensable for climate variability and change studies. This study aims to examine the trend pattern of rainfall and temperature over a sub-basin of Lake Chad Hydrological Area. To achieve this, rainfall and temperature datasets over 50 years (1970-2020) were analysed for variability and trends using descriptive statistics and Mann Kendal Trend Analysis. The results showed that the area has experienced a mean annual rainfall of 751.13 mm yr−1 with a standard deviation of 136.58 mm yr−1. Rainfall variability was high (CV >30) in the early rainy but less (i.e., CV <20) in the annual and late rainy season. The highest mean value was noted for TMIN, TMAX and TMEAN in the months of April and May and their highest variability was in the months of January and February. Also, an increasing trend in rainfall pattern that is significant (p<0.05) had been recorded in the late rainy season and annual timescale. Except for the TMAX (i.e., the day temperature) that showed an upward but non-significant trend, the remaing temperatures (TMIN and TMEAN) showed upward trends of varying levels of significance on seasonal and annual bases. This implies that the area has been experiencing a warming trend with effects on rainfall that has probably attracted the flood witnessed in part of the Lake Chad Hydrological Area.