Increased Extreme Flooding Events in the Sahel Due to Climate Change Dynamics

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A recent analysis shows that extreme flooding events in the Sahel are expected to increase in both frequency and intensity due to changes in African easterly waves (AEWs) exacerbated by climate change. The study uses Earth system models to predict these shifts and highlights the implications for Saharan dust transport and tropical cyclone development as AEW activity rises in the region.

A recent study has indicated that extreme flooding events in the Sahel region will likely increase in frequency and intensity due to significant changes in African easterly waves (AEWs) driven by climate change. These weather systems are crucial as they influence precipitation patterns across drought-affected areas of northern Africa while also transporting Saharan dust and seeding hurricanes in the Atlantic. Researchers utilized a multitude of Earth system models to project changes in AEWs under various emission scenarios.

The study’s findings reveal a correlated rise in AEW activity in the Sahel-Sahara region by the close of the 21st century, specifically linked to increased baroclinicity. This condition arises from a strengthened temperature gradient between the Guinea Coast and the Sahara. Additionally, the researchers identified that warming at lower atmospheric levels bolsters AEWs by accentuating monsoon flows, thus increasing convergence and vertical motion along the intertropical discontinuity. Such transformations in conditions are expected to elevate the occurrence of significant flooding in the region.

The anticipated rise in AEW activity has notable implications for the transport of Saharan dust. Regions poised for the most substantial increases in AEW occurrence coincide with rich dust sources in western Sahara. Notably, the influence of AEWs is multifaceted; they can either delay the formation of tropical cyclones or, alternatively, inhibit such formations altogether based on their trajectory and the surrounding environmental conditions. The paramount findings of this study underscore AEWs’ critical role in modulating climate patterns and precipitation in the Sahel, particularly during the West African monsoon season.

Prof. Akintomide A. Akinsanola from the University of Illinois emphasized the influence of AEWs, stating that, “Strong winds associated with a northern track AEW can transport dry Saharan air downstream… delaying tropical cyclogenesis until the wave reaches more favorable environmental conditions farther west in the Atlantic basin, where sea surface temperatures are warmer.”

The article discusses the impact of climate change on the intensity and frequency of flooding events in the Sahel region. It highlights the role of African easterly waves (AEWs) in influencing weather patterns and their implications for regional hydroclimates. The findings from this research illustrate how global warming could affect AEW activity, leading to increased precipitation and its subsequent consequences on flooding in drought-prone areas of northern Africa. Furthermore, the study underscores the interconnectedness of AEWs with dust transport and tropical cyclone formations in the Atlantic.

The study clearly demonstrates that the intensification of African easterly wave activity will likely have significant ramifications for the Sahel region, particularly regarding increased flooding events due to climate change. As AEWs are projected to become more active, the implications extend to Saharan dust transport and the functioning of tropical cyclone systems. Hence, understanding AEWs’ dynamics is crucial for developing better predictive models related to future climate and weather patterns in the Sahel.

Original Source: www.downtoearth.org.in

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