Inversion breakup in small Rocky Mountain and Alpine basins

Author(s)
Charles David Whiteman, Bernhard Pospichal, Stefan Eisenbach, Philipp Weihs, Craig B. Clements, Reinhold Steinacker, Erich Mursch-Radlgruber, Manfred Dorninger
Abstract

Comparisons are made between the postsunrise breakup of temperature inversions in two similar closed basins in very different climate settings, one in the eastern Alps and one in the Rocky Mountains. The small, high-altitude, limestone sinkholes have both experienced extreme temperature minima below -50°C and both develop strong nighttime inversions. On undisturbed clear nights, temperature inversions reach to 120-m heights in both sinkholes but are much stronger in the drier Rocky Mountain basin (24 vs 13 K). Inversion destruction takes place 2.6-3 h after sunrise in these basins and is accomplished primarily by subsidence warming associated with the removal of air from the base of the inversion by the upslope flows that develop over heated sidewalls. A conceptual model of this destruction is presented, emphasizing the asymmetry of the boundary layer development around the basin and the effects of solar shading by the surrounding ridgeline. Differences in inversion strengths and postsunrise heating rates between the two basins are caused by differences in the surface energy budget, with drier soil and a higher sensible heat flux in the Rocky Mountain sinkhole. Inversions in the small basins break up more quickly following sunrise than for previously studied valleys. The pattern of inversion breakup in the non-snow-covered basins is the same as that reported in snow-covered Colorado valleys. The similar breakup patterns in valleys and basins suggest that along-valley wind systems play no role in the breakups, since the small basins have no along-valley wind system. Œ 2004 American Meteorological Society.

Organisation(s)
Department of Meteorology and Geophysics, Department of Geography and Regional Research
External organisation(s)
Pacific Northwest National Laboratory, Universität Wien, Universität für Bodenkultur Wien, University of British Columbia (UBC)
Journal
Journal of Applied Meteorology
Volume
43
Pages
1069-1082
No. of pages
14
ISSN
0894-8763
DOI
https://doi.org/10.1175/1520-0450(2004)043<1069:IBISRM>2.0.CO;2
Publication date
2004
Peer reviewed
Yes
Austrian Fields of Science 2012
1030 Physics, Astronomy
Sustainable Development Goals
SDG 13 - Climate Action
Portal url
https://ucris.univie.ac.at/portal/en/publications/inversion-breakup-in-small-rocky-mountain-and-alpine-basins(42ab2aa1-8159-4c42-ae72-cb3129c1e781).html