Abstract:
Climate variability and change constitute major challenges for Africa, especiallyWest Africa
(WA), where an important increase in extreme climate events has been noticed. Therefore, it appears
essential to analyze characteristics and trends of some key climatological parameters. Thus, this study
addressed spatiotemporal variabilities and trends in regard to temperature and precipitation extremes
by using 21 models of the Coupled Model Intercomparison Project version 6 (CMIP6) and 24 extreme
indices from the Expert Team on Climate Change Detection and Indices (ETCCDI). First, the CMIP6
variables were evaluated with observations (CHIRPS, CHIRTS, and CRU) of the period 1983–2014;
then, the extreme indices from 1950 to 2014 were computed. The innovative trend analysis (ITA), Sen’s
slope, and Mann–Kendall tests were utilized to track down trends in the computed extreme climate
indices. Increasing trends were observed for the maxima of daily maximum temperature (TXX)
and daily minimum temperature (TXN) as well as the maximum and minimum of the minimum
temperature (TNX and TNN). This upward trend of daily maximum temperature (Tmax) and
daily minimum temperature (Tmin) was enhanced with a significant increase in warm days/nights
(TX90p/TN90p) and a significantly decreasing trend in cool days/nights (TX10p/TN10p). The
precipitation was widely variable overWA, with more than 85% of the total annual water in the study
domain collected during the monsoon period. An upward trend in consecutive dry days (CDD) and
a downward trend in consecutive wet days (CWD) influenced the annual total precipitation on wet
days (PRCPTOT). The results also depicted an upward trend in SDII and R30mm, which, additionally
to the trends of CDD and CWD, could be responsible for localized flood-like situations along the
coastal areas. The study identified the 1970s dryness as well as the slight recovery of the 1990s, which
it indicated occurred in 1992 over West Africa.
