Impact of Saharan air layer on hurricane peak intensity

[1] The Saharan air layer (SAL), which is associated with African dust outbreaks, forms as air moves across the Sahara Desert, containing substantial amounts of mineral dust. While the relationships of Sahel rainfall with African dust outbreaks and Atlantic hurricane activity have been documented in previous studies, analyses of various independent datasets show that the Sahel rainfall, SAL activity and hurricane peak intensity in the Atlantic basin are highly correlated. The long-term trend in hurricane peak intensity generally follows the Sahel rainfall and SAL activity. The decreasing trend in hurricane intensity by the mid-1980s was associated with the enhancing SAL activity (drying relative humidity and enhancing vertical shear) and the severe drought in the Sahel, while the recent moderate increasing trend in hurricane intensity is consistent with the weakening SAL activity (wetting relative humidity, weakening vertical shear and decreasing dust load) and the ameliorating Sahel drought. This study suggests that the SAL may act as a link between the summer African monsoon and Atlantic hurricane activity.

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