88th Annual Meeting (20-24 January 2008)

Monday, 21 January 2008: 10:00 AM
Forcing of Sahel rainfall change and variability in the CMIP models
217-218 (Ernest N. Morial Convention Center)
Michela Biasutti, Lamont-Doherty Earth Observatory, Palisades, NY
We present a statistical analysis of the pre-industrial, 20th century and A1B scenario simulations performed by thirteen modeling groups in preparation for the IPCC fourth assessment report. We show that the relationship that links Sahel rainfall anomalies to tropical SST anomalies at interannual time scales in observations is reproduced by a vast majority of models in all simulations, independently of the change in the basic state as the world warms. Moreover, the same SST/Sahel relationship can be used to predict the simulated 20th century changes in Sahel rainfall from each model's simulation of changes in Indo-Pacific SST and Atlantic SST meridional gradient. Conversely, such a relationship does not explain the rainfall trend in the 21st century in a majority of models.

Supplementary URL: http://www.ldeo.columbia.edu/~biasutti/Sahel_JC2008.pdf