During the 1970s and 1980s, the Sahel experienced a drastic drought with rainfall reduced by ~20% compared to the 1950s and 1960s. Since 1990, a recovery is observed with a rapid increase in the frequency of occurrence of extreme precipitation events (EPEs) and this trend is expected to persist with global warming. Over the past 10 years, there has been a surge of interest in documenting the statistical properties and studying the physical mechanisms involved in the occurrence of EPEs over the Sahel and West Africa in general through case studies and studies based very often on some portions of the region depending on data availability. It is still a challenge to generalize the conclusions of these studies to the entire region due to the low density of the rain-gauge network. Satellite observations offer an interesting alternative for the study of EPEs. However, these observations also suffer from a lack of in-situ data for their calibration in a large part of the Sahel.
In this seminar, we will discuss the properties of EPEs over the Sahel that are robust in rain-gauge and satellite based rainfall observation products and draw attention to those that are not robust. It will also discuss how the uncertainties in rainfall products affect studies on the mechanisms of interannual variability of EPEs over the Sahel in relation to the surface temperature of the tropical Atlantic.
This seminar will be based on the below paper findings and work in progress.
Sanogo et al. (2022), Extreme Precipitating Events in Satellite and Rain Gauge Products over the Sahel. JCL, DOI:https://doi.org/10.1175/JCLI-D-21-0390.1