Evolution of Extreme Rainfall and Temperature Indices in the Nakambé Watershed at the Bagré Outflow (Burkina Faso)

Abstract

Climate change is now a global phenomenon with serious implications for many countries. Like other countries in sub-Saharan Africa, Burkina Faso is also vulnerable to the extreme effects of climate change, although few studies have been carried out, even though several vital sectors, such as agriculture and the livestock, forestry are strongly affected. The objective of this work is to study the evolution of rainfall and temperature extremes in the Nakambé watershed at the synoptic stations of Ouagadougou, Ouahigouya and Pô. ClimPACT2 was used to calculate the extreme rainfall and temperature indices. The results show that cumulative rainfall above the 95th percentile (R95p) increases by 147.2 mm and 141.3 mm respectively in Ouahigouya and Ouagadougou. However, in Pô, a slight downward trend in the index (-0.17 mm) was observed. Cumulative extremely wet rainfall (R99p) is increasing at all stations. The frequencies of cold nights (TN10p) and cold days (TX10p) are decreasing while those of warm nights (TN90p) and warm days (TX90p) are increasing. The application of break detection tests to rainfall indices shows breaks in the time series. The PETTITT, HUBERT and LEE and HEGHINIAN tests show a break in 2008 for the PRCPTOT index in Ouagadougou with an excess of 20.8% from 2009 to 2018. With these same tests, a break is detected in 2006 in Ouahigouya on the same index followed by a 29.5% surplus