Extreme Sahelian Rainfall Continues to Rise Despite Stable Storm Frequency
- Author(s)
- Dorian Spät, Michela Biasutti, Aiko Voigt
- Abstract
Since the 1980s, Sahel rainfall totals, extreme rainfall, and the share of rainfall from extreme events have all trended upward. In observational and reanalysis data sets, these increases are linked to trends in mesoscale convective systems (MCSs) and extreme deep convection (cold clusters). Throughout this period, precipitation metrics have increased first via increases in MCS frequency and the relative increase in cold clusters, and later via an increase in storm precipitation intensity. Until the late 2000s, increases in the frequency of strong storms were supported by increased vertical shear of the zonal wind, as the African easterly jet intensified in response to the strengthening meridional temperature gradient over the Sahel. Afterward, the storm frequency and vertical wind shear stopped increasing. Yet, extreme precipitation continued to increase, as the storms' precipitation intensity increased. We link the higher precipitation intensity to an increase in atmospheric moisture in both the boundary layer and aloft.
- Organisation(s)
- Department of Meteorology and Geophysics
- External organisation(s)
- Lamont-Doherty Earth Observatory
- Journal
- Geophysical Research Letters
- Volume
- 52
- ISSN
- 0094-8276
- DOI
- https://doi.org/10.1029/2025GL115942
- Publication date
- 08-2025
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105204 Climatology
- Keywords
- ASJC Scopus subject areas
- Geophysics, General Earth and Planetary Sciences
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/5d665b7b-87a7-44f9-8b87-106111a6265c