Processes driving deep convection over complex terrain

Author(s)
U. Corsmeier, N. Kalthoff, C. Barthlott, F. Aoshima, A. Behrendt, P. Di Girolamo, M. Dorninger, J. Handwerker, C. Kottmeier, H. Mahlke, S. D. Mobbs, E. G. Norton, J. Wickert, V. Wulfmeyer
Abstract

The 'Convective and Orographically-induced Precipitation Study' (COPS) analyses the processes driving deep convection over complex terrain. Convection initiation (CI) is mainly not only expressed by a single process, but by a variety of them, which interact on different scales in time and space and finally can lead to deep convection. A study of such a case over inhomogeneous terrain is presented in this article. Data from the COPS network of stations are taken to identify the time and location of CI. In many cases this is not the same location as the first convective clouds, showers or even thunderstorms. It is shown that the interaction of the CI processes on multiple scales locally leads to either deep convection and severe storms or calm weather. The boundary conditions between the different outcomes are narrow. During IOP 9c (20 July 2007), a mesoscale convective system (MCS) embedded in a surface low over eastern France propagated north-eastward and a gust front of the MCS reached the COPS area. During the passage of the gust front through the Rhine valley, convective activity was significantly reduced. The gust front reached the slope of the Black Forest, and the warm and humid air above the mountain range prior to the gust front was lifted up to 2000 m within a short time period. Within the air prior to the gust front aloft from the surface, CI started along a north-south oriented line above the crest. Due to insolation ahead of the gust front, a convergence line developed. The interaction of local-scale orographic winds, the regional-scale gust front, the mesoscale convergence line, and the synoptic-scale cold front led to a squall line. Finally, individual severe convective cells formed along the outer section of the synoptic-scale cold front.

Organisation(s)
Department of Meteorology and Geophysics
External organisation(s)
Karlsruher Institut für Technologie, Universität Hohenheim, Università degli Studi della Basilicata, University of Leeds, Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum, University of Manchester
Journal
Quarterly Journal of the Royal Meteorological Society
Volume
137
Pages
137-155
No. of pages
19
ISSN
0035-9009
DOI
https://doi.org/10.1002/qj.754
Publication date
01-2011
Peer reviewed
Yes
Austrian Fields of Science 2012
105208 Atmospheric chemistry
Keywords
ASJC Scopus subject areas
Atmospheric Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/processes-driving-deep-convection-over-complex-terrain(3749cc02-1b30-4a82-8733-29d763890b0f).html