Robust Sahel drying in response to late 20th century forcings

Publication Type  Journal Article
Year of Publication  2006
Authors  Biasutti, M.; Giannini, A.
Journal Title  Geophysical Research Letters
Volume  33
Issue  11
Pages  -
Journal Date  Jun 8
ISBN Number  0094-8276
Accession Number  ISI:000238218400002
Key Words  west-africa; el-nino; rainfall; climate; variability; drought
Abstract  

The African Sahel experienced severe drying between the 1950s and the 1980s, with partial recovery since. We compare Sahel rainfall in the 20th century, pre-industrial, and increased greenhouse gases (GHG) simulations produced for the Intergovernmental Panel on Climate Change (IPCC). The simulations forced by 20th century concentrations of aerosol and GHG reproduce (i) a global change in SST akin to that associated with Sahel drought and (ii) a correspondent drying of the Sahel. We conclude that late 20th century Sahel climate was significantly dryer than pre-industrial, and at least 30% of the drying was externally forced. Comparison between 20th century runs and runs forced by GHG alone reveals the key role of reflective aerosols: they force a gradient in SST that excites robust drying in the northern edge of the Atlantic Inter-Tropical Convergence Zone (ITCZ) and in the Sahel.

Notes  

052FRTimes Cited:3Cited References Count:19

URL  <Go to ISI>://000238218400002
DOI  Doi 10.1029/2006gl026067