caa a22 4500 467938121 CHVBK 20180406153004.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s00703-004-0106-7 doi (NATIONALLICENCE)springer-10.1007/s00703-004-0106-7 Zängl G. Meteorologisches Institut der Universität München, München, Germany aut North foehn in the Austrian Inn Valley: A case study and idealized numerical simulations [Elektronische Daten] [G. Zängl] Summary: This study presents high-resolution numerical simulations of north foehn in the Austrian Inn Valley which have been performed with the Penn State/NCAR mesoscale model MM5. As the Inn Valley is located north of the Alpine crest, north foehn occurs comparatively rarely in this valley, and there are only sparse observations available for this phenomenon. Simulations of the 24 January 1993 case as well as idealized simulations are performed to get a deeper insight into the dynamics of the north foehn. Moreover, the synoptic conditions leading to the occurrence of north foehn in the Inn Valley are investigated. The simulations indicate that there are at least four different paths for the foehn to penetrate into the valley. Two of them are running along side valleys entering the upper Inn Valley from the west. These flow paths appear to be most important when the large-scale flow has a significant westerly component. The other possible flow paths enter the Inn Valley from the northwest or north and require a strong northerly component of the large-scale flow. From a dynamical point of view, north foehn appears to be similar to the well researched south foehn in that vertically propagating gravity waves force the descent of the ambient flow into the valleys. However, there are also indications that trapped lee waves have a significant impact on the surface wind field, which has not been reported for south foehn so far. Moreover, the model results show that a precondition for the formation of north foehn in the Inn Valley is the absence of significant orographic precipitation. Evaporative cooling induced by precipitation falling into subsaturated air not only reduces the surface temperatures but also inhibits the formation of large-amplitude gravity waves, suppressing the development of stormy surface winds. Springer-Verlag/Wien, 2005 Meteorology and Atmospheric Physics Springer-Verlag 91/1-4(2006-01-01), 85-105 0177-7971 91:1-4<85 2006 91 703 https://doi.org/10.1007/s00703-004-0106-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00703-004-0106-7 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Zängl G. Meteorologisches Institut der Universität München, München, Germany aut NATIONALLICENCE 773 0- Meteorology and Atmospheric Physics Springer-Verlag 91/1-4(2006-01-01), 85-105 0177-7971 91:1-4<85 2006 91 703 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer