Rainfall & Climate in the Horn of Africa

The severe drought in 2010-2011 across the Horn of Africa caused widespread famine and a humanitarian crisis. Such events remind us of how vulnerable this region is to climate variability. Though we know that El Niño can affect precipitation in this region, long-term (decadal and longer) controls on rainfall have not been extensively studied, making future prediction of drought and food security challenging. With support from the National Science Foundation, we are developing the first paleoclimate record of rainfall in the Horn of Africa region, based on hydrogen isotopes measured on terrestrial leaf waxes. We will also reconstruct local SSTs in the Gulf of Aden, and use climate model simulations to understand the influence that the Indian and Pacific Oceans may have on changes in precipitation on the decadal and centennial scale.
(Photo courtesy of OxFam East Africa)

Relevant Papers

Multidecadal variability in East African hydroclimate controlled by the Indian Ocean
Jessica E. Tierney, Jason E. Smerdon, Kevin J. Anchukaitis and Richard Seager Nature, 493, 389-392.
Multidecadal variability in East African rainfall is an important but poorly understood component of the climate of the region. Here we use paleoclimate records of relative moisture balance from the last millennium and general circulation model simulations to provide perspective on multidecadal variability in East Africa and insight on the mechanisms that drive it.
Abrupt shifts in Horn of Africa hydroclimate since the Last Glacial Maximum
Jessica E. Tierney & Peter B. deMenocal, Science, 342, 843-846.
The timing and abruptness of the initiation and termination of the Early Holocene African Humid Period are a subject of ongoing debate. Here we provide proxy evidence from the Horn of Africa region that documents abrupt transitions into and out of the African Humid Period in northeast Africa. Similar and generally synchronous abrupt transitions at other East African sites suggest that rapid shifts in hydroclimate are a regionally coherent feature. Our analysis suggests that the termination of the African Humid Period in the Horn of Africa occurred within centuries, underscoring the non-linearity of the region's hydroclimate.