Author(s)

Mouhammed Fall^1*, Abdou L. Dieng¹, Laurence Eymard², Gaëlle De Coëtlogon², Saidou M. Sall¹, Youssouph Sane³

¹Laboratoire de Physique de l’Atmosphère et de l’Océan-Siméon Fongang (LPAO-SF), École Supérieure Polytechnique, Université Cheikh Anta Diop, Dakar, Sénégal.
²Laboratoire Atmosphère et Observations Spatiales (LATMOS), Sorbonne Université, Paris, France.
³Agence Nationale de l’Aviation Civile et de la Météorologie (ANACIM), Dakar, Sénégal.

The period of the 70s and 80s was marked by a drought in the Sahelian countries. However, since the beginning of the 21^st century, these countries have experienced a resurgence of heavy rainfall and devastating floods, causing inestimable socio-economic damage and losses. The objective of this work is to study the dynamics of atmospheric conditions associated with seventeen extreme rainfall events listed in the database of the Directorate of Civil Protection of Senegal and having caused significant socio-economic impacts between 2000 and 2017. This study was carried out using satellite products and atmospheric reanalysis data. The results of the analyses of the various atmospheric parameters studied show, at the synoptic scale, that extreme rainfall events are mainly modulated by African easterly waves. Strong moisture transport convergences in the lower tropospheric layers due to vortices associated with these waves are recorded. A response of this moisture convergence in the lower layers accompanied by vertical moisture transport is highlighted by strong anomalies and wind divergence. This configuration corresponds to the presence of a vertically well-structured convective system. The analysis of atmospheric parameters such as relative vorticity, wind, relative humidity and precipitable water shows that they are good indicators to characterize rainfall extremes. The behavior of the anomalies of these variables shows the presence of a significant amount of moisture in the tropospheric column and the most marked pressure levels are between 850 and 700-hPa, and in the upper layers around 200-hPa.

Extreme Rainfall Events, Convective Systems, African Easterly Waves, Climate Dynamic, Climate Change, Climate Impacts

Fall, M. , Dieng, A. , Eymard, L. , Coëtlogon, G. , Sall, S. and Sane, Y. (2025) Atmospheric Dynamics of Extreme Precipitation over the West African Sahel. American Journal of Climate Change, 14, 119-145. doi: 10.4236/ajcc.2025.141007.