P3.2
Use of Wind-Temperature profiler Data to Investigate Foehn Episodes During MAP-FORM
Siegfried Vogt, Institut f. Meteorologie u. Klimaforschung , Forschungszentrum, Karlsruhe, Germany
One of the scientific objectives of the subprogramme FORM addressed the four-dimensional variability of the Foehn flow in the Rhine valley.To investigate Foehn phenomena a very dense observing network was installed during the MAP special observing period in the Rhine valley target. Our wind-temperature profiler was continuously operating in the middle of the Rhine valley south of Lake Constanze.
The profiler has a 5-beam geometry for two bistatic radiofrequency (rf) and for one acoustic (a) antennas. The rf and a antennas are emitting continuous waves that are frequncy modulated with a saw tooth (FM-CW-Doppler-RADAR), to provide high average transmitted power.Thanks to this unique technical design redundant wind profiles are derived for both the clear air and the RASS signal with high resolution in time and height. The temperature profiles are estimated simultaneously from the RASS signal.
During 77 days of mesurements there were 17 days with South Foehn at the profiler site. We will present wind and temperature information (time series and 2D plots) of two selected Foehn episodes. In the first case the cold air pool in the valley was removed slowly but steadily. In the second case the warm Foehn air didn't reach the valley floor.
Poster Session 3, Topographic Flows (with Coffee Break)
Thursday, 20 June 2002, 2:45 PM-4:30 PM
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