The Multidecadal Atlantic SST—Sahel Rainfall Teleconnection in CMIP5 Simulations

• DOI: 10.1175/jcli-d-13-00242.1
• Publication Date: 2013-09-25T01:34:25Z
• Authors: Elinor R. Martin; Chris Thorncroft; Ben B. B. Booth
• Keywords: Teleconnection

Abstract This study uses models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) to evaluate and investigate Sahel rainfall multidecadal variability teleconnections with global sea surface temperatures (SSTs). Multidecadal is lower than observed in all historical simulations evaluated. Focus on North Atlantic SST [Atlantic (AMV)] as it more successfully simulated Indian Ocean teleconnection. To why some this teleconnection others did not, despite having similarly large AMV, two groups were selected. Models AMV highlighted good (or poor) by their ability simulate relatively high (low) have significant (not significant) correlation between an index. Poor fail capture because spatial distribution across incorrect. A lack signal tropical Mediterranean reduces interhemispheric gradient and, through circulation changes, Sahel. pattern was also evident control simulations, where significantly weaker simulations. Errors suggested result a combination weak wind–evaporation–SST feedbacks, poorly cloud amounts feedbacks stratocumulus regions eastern Atlantic, dust–SST–rainfall sulfate aerosol interactions clouds. By understanding deficits successes CMIP5 future projections decadal hindcasts can be examined additional confidence.