Test of a mesoscale model over the south west Indian ocean for cyclones analysis and prediction

A limited area assimilation/prediction system has been built over the south west Indian ocean for cyclones forecasting. The horizontal resolution of both analysis and prediction is significantly improved compared to the global models. Moreover, to focus over a tropical area allows to implement specific tunings in the assimilation : for instance, the background error covariances have been estimated over the warm season, ie the cyclonic period, by using the ensemble technique. Compared to its coupling model, this mesoscale model is much more able to simulate well defined cyclonic structures. This capability has a direct impact on the forecast quality which is significantly improved.