Département de Physique, Laboratoire d’Océanographie, des Sciences de l’Environnement et du Climat (LOSEC), Université Assane SECK de Ziguinchor, Senegal
The objective of this study is to estimate the potential changes in extremes rainfall over three orographic regions of Africa (Guinea, Nigeria and Cameroon) under the 1.5°C and 2°C warming scenarios. The results project an increase of the number of rainy days over Guinea under both scenarios by 2059. Over Nigeria, this index will decrease in the north of the country under both scenarios. Over Cameroon, this index will decrease over the whole country under the 1.5°C warming and will increase in the southeast and northeast parts of the country under the 2°C warming. Rainfall intensity will increase over the northern and southwestern parts of Guinea under both scenarios. The maximum one-day rainfall accumulation will increase in almost all three considered countries in the near future. However, compared to Cameroon, the maximum one-day rainfall accumulation will be more important in the northern and central parts of Guinea and Nigeria. There will be a decrease of the number of consecutive wet days in the southwest and central parts of Guinea under the 1.5°C scenario and over most parts of Guinea under the 2°C scenario. Over Nigeria, this index will decrease in the south and center of the country. The number of consecutive wet days will decrease in the southwest and northern Cameroon and increase slightly in the southeast of this country under both warming scenarios. The number of consecutive dry days will decrease over the whole Guinea, over the northern and central parts of Nigeria under both scenarios. The increase noted in extreme events could cause flooding. This work can be considered as a support for the Guinean, Nigerian and Cameroon policymakers for implementing sustainable mitigation and good adaptation measures to limit and combat the adverse effects of climate change (floods, heat waves and drought). Finally, this study shows that the three considered regions will need additional irrigation as an adaptation strategy for the protection of the agricultural sector by 2059 under both scenarios due to the decrease of the number of consecutive wet days.