caa a22 4500 469052759 CHVBK 20180323132834.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF01025610 doi (NATIONALLICENCE)springer-10.1007/BF01025610 A mechanism of Alpine lee cyclogenesis as revealed by a quasigeostrophic variational filter [Elektronische Daten] [Yoshi Sasaki, Milija Zupanski] Summary: Mechanisms associated with Alpine lee cyclogenesis during the early phase of their generation are investigated using a variational quasigeostrophic filter technique. It was possible to extract the quasigeostrophic signal from the available analyzed real data set. The results presented here are for the 11-12 March 1982, an example of so-called "orographically induced” lee cyclogenesis. Non-quasigeostrophic fields, calculated as a difference between observations and the quasigeostrophic fields, show significant magnitudes indicating the possible importance of non-quasigeostrophic processes. A "dipole” structure in the residual geopotential field was observed, similar to the results of numerical model experiments. Also, a strong upper-level non-quasigeostrophic divergence was found in the Alpine region 24 hours prior to lee cyclogenesis, lasting for 6-12 hours. On the other hand, quasigeostrophic results indicate only a local effect of mountain slopes, suggesting possibly a dominant role of the low-level blocking. A hypothetical "scenario” of Alpine lee cyclogenesis is proposed, based on results obtained here. Springer-Verlag, 1992 Sasaki Yoshi School of Meteorology, University of Oklahoma, 200 Felgar Street, 73019, Norman, OK, USA aut Zupanski Milija NOAA/National Meteorological Center, 20233, Washington, DC, USA aut Meteorology and Atmospheric Physics Springer-Verlag 47/2-4(1992-06-01), 91-105 0177-7971 47:2-4<91 1992 47 703 https://doi.org/10.1007/BF01025610 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01025610 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sasaki Yoshi School of Meteorology, University of Oklahoma, 200 Felgar Street, 73019, Norman, OK, USA aut NATIONALLICENCE 700 1- Zupanski Milija NOAA/National Meteorological Center, 20233, Washington, DC, USA aut NATIONALLICENCE 773 0- Meteorology and Atmospheric Physics Springer-Verlag 47/2-4(1992-06-01), 91-105 0177-7971 47:2-4<91 1992 47 703 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer