NEWS BRIEFS

Manno, Switzerland — On September 7, one of the largest field experiments ever in Alpine meteorological history began, with the objective to make a major contribution to current problems in weather forecasting, with particular regard to extreme events such as heavy precipitation, river run-off and flooding. The Mesoscale Alpine Program (MAP) is a collaboration of several hundred scientists from national weather services; university institutions; prominent research institutes such as the US National Center for Atmospheric Research (NCAR), Environment Canada, the Centre National de la Recherche Scientifique (CNRS, France); and from the World Meteorological Organization. MAP was initiated by Swiss researchers in 1994. Currently the Swiss Meteorological Institute (SMA) hosts the MAP Programme Office, and the Data Center is at the ETH Zurich.

Computer simulations at unprecedented resolution with prospects for substantial improvements of weather prediction are one of the key motivations for MAP. They also play a crucial role for the success of the MAP field experiment. Such simulations are extremely complex and can only be computed with today’s most powerful supercomputers. The highest resolution model utilized is the Canadian MC2 code, one of the most advanced latest-generation weather prediction programs. It is run in a collaborative effort between Environment Canada, ETH Zurich, the Swiss Meteorological Institute (SMA) on the NEC SX-4 parallel-vector supercomputer of the Swiss Center for Scientific Computing (CSCS). CSCS is also equipped with state-of-the-art data management systems capable of coping with the enormous volume of MC2 simulation data that will be generated in the course of the MAP field phase.

The Alpine region is traditionally known for its extraordinary coverage by meteorological measurement instruments. Three regions of particular interest have been selected for the MAP experiment due to their known frequent occurrence of typical alpine weather conditions: to the south of the Alps the Swiss/Italian Lago Maggiore region for strong precipitation and flood events, to the north of the Alps the Rhine valley and the Brenner passage in Austria for Fohn-like windstorm events. The already excellent permanent measurement equipment for these regions has been specially enhanced with sophisticated instruments such as RADAR, extra stations for radio probes, windprofilers, etc.

During 70 days from September 7 to November 15, measurements at extraordinary precision both in space and time will be taken in order to build up a meteorological database of unprecedented completeness and accuracy. This database will allow the researchers to test new advanced forecasting models in order to investigate and improve the models’ abilities to predict extreme local weather conditions such as e.g. the disastrous flooding of Brig (Valais, Switzerland, September 1993), or of Piedmont (Italy, November 1994). The fact that the underlying physical and atmospheric processes bear universal characteristics has stimulated broad international interest into MAP, far beyond the Alpine region. Results from the project will be applied to many mountain ranges throughout the world.

Land-based observations receive further support from eight special research aircraft equipped with highly sophisticated measurement instruments, such as Doppler RADAR. They can reach in a brief time the most interesting locations of critical weather development in the atmosphere and take additional highest-resolution measurements by in-situ and remote-sensing instruments. The operations center for the MAP field phase will be located at Innsbruck airport. Furthermore, full dedication to MAP of METEOSAT6 for satellite monitoring at 5-minute intervals will substantially contribute with most precise tracking of cloud development.

Numerical weather forecasts play a central role during the MAP field experiment. They need to provide timely warnings for the activation of measurement systems, and for the take-off of the aircraft and their direction to the locations of interest. Every night from 11 PM to 4 AM, the leading-edge MC2 model will be run on the dedicated 12-CPU NEC SX-4 at CSCS and produce a daily forecast at an unprecedented spatial resolution of 3 km, compared to the 14 km of today’s model of the Swiss Meteorological Institute. This resolution will describe the weather development in the Alpine area to a fine scale of features that was unattainable to date.

For more information visit http://www.cscs.ch/ or http://www.map.ethz.ch

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