Implementation of the Limited-Area Numerical Weather Prediction Model Aladin in Distributed Memory

The technical challenges for the limited area model Aladin are various: Aladin is the French operational mesoscale model, run on the Météo-France VPP-700E on 4 processors twice a day. Also, the model is used in operational or pre-operational mode in several European countries, plus Morocco, and therefore the model has to be portable and computationally efficient on several platforms. In the presentation, the general choices for the porting of Aladin in a parallel environment will be discussed, with an emphasis to Aladin-specific aspects, the general choices being closely related to those of Arpège. Finally, the question of applications to workstation clusters will be addressed.