The Mesoscale Alpine Programme MAP :
A significant effort to improve weather prediction in the Alpine area


Preamble:          
Heavy precipitation, flash floods but also windstorms are of central importance
for the weather in the Alpine area. Severe weather during fall on the southern side of
the Alps has caused more than 80 losses of lives and more than 10 Billions Euros
of damages during the last 6 years. Timely and accurate prediction of such
events hold a potentially large benefit for society as catastrophic consequences
of severe weather could  be mitigated given precise early warning.

The Mesoscale Alpine Programme:                  
	From 7 September to 15 November 1999, an international consortium of Science Agencies and 
Weather Services will conduct the largest observational field program of meteorology over the Alps since 
ALPEX in 1982.
The objective of this program, called the Mesoscale Alpine Programme or MAP, is to improve basic 
understanding and prediction techniques of severe precipitation and flash floods, strong surface winds in 
Alpine valleys, and high altitude turbulence generated by mountain waves.

Severe precipitation and flash floods:
	Mountainous terrain tends to facilitate the formation of extremely intense rainfall (up  to 300 mm in 
a few hours) on small areas (a few hundred km2). When happening on sensitive watersheds, these events 
can generate in a few hours rapid and destructive floods, as experienced for instance in Vaison la Romaine 
(France, September 1992) and Brig (Switzerland, September 1993). Current weather prediction techniques, 
based on numerical models with a moderate resolution of 10 to 40 km, can now anticipate the risk of heavy 
rainfall, but are unable to represent precisely the timing and the location of these events. A new generation of 
numerical models, with resolution as high as one kilometer, is offering good hope of improvement of the 
forecast skill. However, very accurate measurements of the atmospheric flow and cloud properties are 
needed to develop the best formulations and usages for these models. These will be taken during MAP. The 
prediction of river flow will also be attempted during MAP by coupling hydrologic models with rainfall 
observed and predicted by atmospheric models.  Surface winds and altitude turbulence 

The Foehn or the Mistral 
	are well known examples of severe surface winds generated in Alpine valleys by specific dynamic 
processes that can now be represented in numerical models. They represent a danger for all transportation, 
construction, and outdoor activities, and impact on air quality issues. Turbulence at high altitude (5 to 15 km) 
is often generated by the breaking of mountain waves, and represent a threat to air traffic. The new 
generation of numerical models have a potential capacity to predict all these events much more accurately 
than in the past, and will be tested and improved through special measurements during MAP. 

Institutions and Facilities involved in MAP
	More than 200 scientists and engineers are involved in MAP, a ten years long cooperative research 
program which will culminate with the field campaign of 1999, for a total budget of about 20 Millions 
Euros. Initially proposed by the Swiss Meteorological Institute and the Federal Institute of Technology (ETH 
Zurich), the program was joined over the years by the weather services and science agencies of 13 countries 
(Austria, Canada, Croatia, France, Germany, Greece, Hungary, Italy, Slovakia, Slovenia, Spain, UK, USA), 
under the auspices of the World Meteorological Organization.



The results of MAP
	Like all field projects in meteorology, MAP is highly dependent on weather. If the weather is close 
to the climatology, we expect to run about 10 intensive observation periods of several days. After each 
period, we will report on our investigations and try to draw the lessons for the next period. The press will be 
informed of this continuing process. However, the final result will be achieved only when the numerical 
models will have been able to simulate  accurately the most important events, and when we will have 
acquired a reasonable understanding of what input data are necessary to achieve these good simulations. 
This may not come before a few years. One important outcome may be the design of a new routine 
observational system and the progressive operational use of the numerical models which have best 
performed on MAP cases.