The role of the Sahara low in summertime Sahel rainfall variability and change in the CMIP3 models

Biasutti, Michela; Sobel, Adam H.; Camargo, Suzana J.

Projections for twenty-first-century changes in summertime Sahel precipitation differ greatly across models in the third Coupled Model Intercomparison Project (CMIP3) dataset and cannot be explained solely in terms of discrepancies in the projected anomalies in global SST. This study shows that an index describing the low-level circulation in the North Atlantic–African region, namely, the strength of the low-level Saharan low, correlates with Sahel rainfall in all models and at the time scales of both interannual and interdecadal natural variability and of the forced centennial trend. An analysis of Sahel interannual variability provides evidence that variations in the Sahara low can be a cause, not just a consequence, of variations in Sahel rainfall and suggests that a better understanding of the sources of model discrepancy in Sahel rainfall predictions might be gained from an analysis of the mechanisms influencing changes in the Sahara low.



  • thumnail for biasutti_sobel_camargo_jclim09.pdf biasutti_sobel_camargo_jclim09.pdf application/pdf 2.08 MB Download File

Also Published In

Journal of Climate

More About This Work

Academic Units
Lamont-Doherty Earth Observatory
Applied Physics and Applied Mathematics
Earth and Environmental Sciences
Ocean and Climate Physics
American Meteorological Society
Published Here
June 2, 2015