Reinhold Steinacker, Dept. of Meteorology and Geophysics, University of Vienna, Austria
MAP related events were evaluated for the MAP season 2000 (September 7 through November 15) in the same manner as with the
strawman scenario and the evaluation of the actual MAP-SOP in 1999 (cf. MAP Newsletter 10, 1999; MAP Newsletter 12, 2000;
US MAP Field Phase Report, 2000). The question arises whether an SOP in 2000 would have resulted in a better series of weather
events suited for our research or whether 1999 was a stroke of luck?
Table 1 gives an overview of the events in a similar fashion as in the MAP Newsletter 12.
After a first glimpse an "SOP 2000" would seem to look even better than the actual one. A new "10-year record" of days with
PV-streamers occurred and a new "record" for foehn and gap flow events was barely missed. Also the number of days with heavy
precipitation on the south side of the Alps was larger than in 1999. However, gravity waves and PV-banners occurred less often;
especially northerly flows (with PV-banners in the South) were still less frequent than the already small number of the 1999 SOP.
It is interesting to note that the number of possible IOPs would have been smaller than in 1999 due to a longer mean duration of
episodes with MAP related events. The counted 45 (!) days (out of 70) with at least one event - as compared to 34 in 1999 - have
to be interpreted that our personnel and material resources would not have been sufficient to cover the whole SOP.
The most dramatic weather episode occurred between October 9 and 16, 2000, when excessive precipitation amounts were so large that
severe flooding and landslides with several fatalities happened in the Ticino, the Vallais, the Aosta valley and in large parts
of the Po valley. Should we regret that we missed a comparable event in 1999? In my opinion, we should count ourselves fortunate
that we did not have this event. Probably part of our infrastructure in that area would have been destroyed, ground-based
in-situ measurements would not have been possible due to the break-down of power supply and traffic lines. Flying under such conditions
would certainly have led to questions from the public, why we did not predict the exact location of flooding and landslides to save
life. Hence we should see the SOP 1999 as a real stroke of luck. We had exactly the right number of events according to our resources,
the time sequence of events was nearly perfect, still allowing for some breaks to recover. The MAP data set is unique and will be
the key base for investigations in the field of mountain meteorology and hydrology for years. It will certainly help to further
improve the forecasts of severe weather events over the Alps and other mountains of the world in the future.
Table 1 Number of days with MAP related weather events, calculated from a "half day" based
evaluation.
