Abstract:
Climate change has led human beings to take an interest in the study of meteorological and climatic phenomena. In fact, the main impact of climate
change on different sectors of society is caused by extreme events since the
occurrence of extreme events leads to more impact related to change in mean
climate. Unfortunately, the West African region is vulnerable to extreme
rainfall impact because its economy is based on rain-fed agriculture. This
study examined the seasonal variability of extreme rainfall in West Africa.
Eight (8) climate indices were chosen from among the 27 defined by the Expert Team on Climate Change Detection and Indices (ETCCDI). The nonparametric Mann-Kendall test was used to assess the seasonal trends. The indices of the same types (frequency or intensity) were compared to assess the
intra-seasonal variation of extreme precipitation. The results indicate that,
regardless of the season, the Gulf of Guinea receives more rainfall than the
Sahel. This phenomenon is due to the fact that the coastal part of West Africa
is under the influence of evaporation which is observed at the Atlantic Ocean
and during the monsoon, while the other part is dominated by the desert.
Mann-Kendall’s test revealed upward and downward trends during each season. The increase in extreme rainfall trends in the number of consecutive dry
days suggests that droughts, due to global warming, could be observed and
could have severe consequences in terms of water availability, energy supply,
agricultural yields and ecosystems in West Africa. In addition, it can lead to
the loss of biodiversity and health issues. It is therefore essential for policy makers or decisions makers to determine strategies and mitigation measures
against climate change and its impacts on populations.
