Abstract Author: Sharon Nicholson
Abstract Title: The physical basis for drought in West Africa
Abstract: The extreme droughts that plague the West African Sahel have long been shown to be strongly linked to Atlantic and global sea-surface temperatures. Unfortunately, only a handful of studies have attempted to link SSTs to the circulation features that directly drive rainfall variability. This paper emphasizes that link. It examines two types of droughts over West Africa, one linked to an anomalous displacement of the tropical rainbelt/ITCZ and another linked to changes in its intensity. Factors are identified that modulate both the latitudinal displacement and the intensity. These factors are significantly different, as are their associations with SSTs. Forecasts will be improved by considering these very different modes in which droughts in the region can be manifested.