High-Performance Modelling for the Mesoscale Alpine Programme (MAP) Field Experiment

With the development of a version of the Canadian non-hydrostatic MC2 model optimized for massively parallel processors, it has become possible to solve very large weather forecast problems in a time sufficiently short to envision a realtime daily calculation over a domain covering the entire Alps. MAP is a large multinational research program that will gather new knowledge about the heavy precipitation over steep topography; its field phase is to take place during Fall of 1999. The tentative grid dimensions are 490 − 400 − 35 at a horizontal resolution of 2 km, with possibly a need to increase the number of vertical layers. This is a very large problem to be solved with realtime constraints. The model results will be accessible to the forecasters at the MAP Operations Centre in Innsbruck, to assist in the scientific briefings to dispatch the flight plans of the research aircraft. The forecasts are planned to be performed on the NEC-SX/4 (10 PE) at the CSCS (Centro Svizzero di Calcolo Scientifico) in Manno (Canton Ticino, Switzerland), which is affiliated with the ETH. The current state of this joint effort is presented.