Monsoon variability over the Horn of Africa.

Abstract

Over the past several decades, the Horn of Africa has been ravaged by catastrophic droughts and famines. In spite of the devastating frequent droughts and occasional floods in the region, our understanding of the region's weather and climate variability is limited. The present study represents the first exhaustive investigation of rainfall variability over the Horn of Africa at intraseasonal, seasonal, interannual, and multidecadal time-scales, and contributes substantially to the fundamental understanding of weather and climate variability in the region.

This research involves observational and modeling investigations to explore and document the space-time distribution of the major elements of weather and climate and their variability in the Horn of Africa. In particular, an exhaustive diagnostic examination is performed to identify the dominant modes of rainfall variability and the large-scale atmospheric and oceanic features that affect rainfall in the region. Building on the results of the diagnostic study, dependable short- to long-range prediction models are developed. These models are capable of predicting rainfall amounts and anomalies at a specific location or region from a few days to seasons in advance. The modeling study has identified the roles of sea surface temperatures over the Mediterranean Sea, Atlantic, and Indian Oceans in shaping rainfall variability over the Horn of Africa. The impacts of depleted vegetation resulting from poor early rains on Horn of Africa summer rainfall also are investigated and identified through model sensitivity experiments.