African monsoon synoptic variability:: Validation of the Meteo-France GCM

The aim of this study is to describe the African monsoon synoptic variability and investigate the ability of the Meteo-France GCM to reproduce that variability. We used the ECMWF Reanalysis as a reference dataset. The main results about the characterization of the synoptic variability is a "Northern and Continental" mode vs a "Southern and Oceanic" mode. The first one is predominant during the "dry" years while the second one is predominant during the "wet" years. The model failed to capture the pattern of these modes and their interannual variability. Interestingly, the times series of these modes present a Low Frequency Modulation (LFM) both in the Reanalysis and in the model. Looking at this LFM, the improvement of the behavior of the model seems to be related to improvements in the new land/surface scheme. (C) 2000 Elsevier Science Ltd. All rights reserved.