Robust Sahel drying in response to late 20th century forcings
نویسندگان
چکیده
[1] 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 InterTropical Convergence Zone (ITCZ) and in the Sahel. Citation: Biasutti, M., and A. Giannini (2006), Robust Sahel drying in response to late 20th century forcings, Geophys. Res. Lett., 33, L11706, doi:10.1029/2006GL026067.
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