Bougeault, Philippe (CNRM, Meteo-France and CNRS, Toulouse France)
The Mesoscale Alpine Programme MAP is a cooperative long term program concerning all alpine countries, Spain, the USA and Canada. Its objectives are to improve the understanding and numerical forecast of some key weather patterns, strongly influenced by the Alps. Of prime interest are (i) the intense rainfall influenced by orography, leading to flash floods, especially in the fall season, when moist mediterranean air impiges the range from the South; (ii) the braking of gravity waves in the upper atmosphere, and the generation of potential vorticity streamers in the lee of the Alps.
The programme is divided in three phases. The preparatory phase will cover 1996-1998. It allows several groups to run numerical models on selected cases, to establish better climatologies of the events of interest, in order to optimize the observational requirements, and the measurement strategies. This will be followed by a major field experiment, to be held during the fall of 1999. This will feature the deployement of several research aircraft, and the use of research networks of ground doppler radars, wind profilers, and surface measurements.
The MAP experiment will also contain a significant hydrological component. During the preparatory phase, hydrological models are run over several watersheds of interest, both in stand alone mode, and coupled with atmospheric models. During the field phase, special measurements will be done to verify the ability of the models to forecast the stream flow in coupled mode.
The MAP will be an occasion to adress important issues for the scientifice community of mediterranean studies.
Most of the weather events studied in the MAP program are strongly influenced by the Mediterranean. The paper will describe the present results of the preparatory phase, and the experimental plans for the field phase.