Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

“A Theory for Strong Long-Lived Squall Lines” Revisited

“A Theory for Strong Long-Lived Squall Lines” Revisited Based on the analysis of idealized two- and three-dimensional cloud model simulations, Rotunno et al. (hereafter RKW) and Weisman et al. (hereafter WKR) put forth a theory that squall-line strength and longevity was most sensitive to the strength of the component of low-level (0–3 km AGL) ambient vertical wind shear perpendicular to squall-line orientation. An “optimal” state was proposed by RKW , based on the relative strength of the circulation associated with the storm-generated cold pool and the circulation associated with the ambient shear, whereby the deepest leading edge lifting and most effective convective retriggering occurred when these circulations were in near balance. Since this work, subsequent studies have brought into question the basic validity of the proposed optimal state, based on concerns as to the appropriate distribution of shear relative to the cold pool for optimal lifting, as well as the relevance of such concepts to fully complex squall lines, especially considering the potential role of deeper-layer shears in promoting system strength and longevity. In the following, the basic interpretations of the RKW theory are reconfirmed and clarified through both the analysis of a simplified two-dimensional vorticity–streamfunction model that allows for a more direct interpretation of the role of the shear in controlling the circulation around the cold pool, and through an analysis of an extensive set of 3D squall-line simulations, run at higher resolution and covering a larger range of environmental shear conditions than presented by WKR . http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of the Atmospheric Sciences American Meteorological Society

“A Theory for Strong Long-Lived Squall Lines” Revisited

Download PDF
22 pages

Loading next page...
 
/lp/american-meteorological-society/a-theory-for-strong-long-lived-squall-lines-revisited-lhNoV0S6ul

References (41)

Publisher
American Meteorological Society
Copyright
Copyright © 2002 American Meteorological Society
ISSN
1520-0469
DOI
10.1175/1520-0469(2004)061<0361:ATFSLS>2.0.CO;2
Publisher site
See Article on Publisher Site

Abstract

Based on the analysis of idealized two- and three-dimensional cloud model simulations, Rotunno et al. (hereafter RKW) and Weisman et al. (hereafter WKR) put forth a theory that squall-line strength and longevity was most sensitive to the strength of the component of low-level (0–3 km AGL) ambient vertical wind shear perpendicular to squall-line orientation. An “optimal” state was proposed by RKW , based on the relative strength of the circulation associated with the storm-generated cold pool and the circulation associated with the ambient shear, whereby the deepest leading edge lifting and most effective convective retriggering occurred when these circulations were in near balance. Since this work, subsequent studies have brought into question the basic validity of the proposed optimal state, based on concerns as to the appropriate distribution of shear relative to the cold pool for optimal lifting, as well as the relevance of such concepts to fully complex squall lines, especially considering the potential role of deeper-layer shears in promoting system strength and longevity. In the following, the basic interpretations of the RKW theory are reconfirmed and clarified through both the analysis of a simplified two-dimensional vorticity–streamfunction model that allows for a more direct interpretation of the role of the shear in controlling the circulation around the cold pool, and through an analysis of an extensive set of 3D squall-line simulations, run at higher resolution and covering a larger range of environmental shear conditions than presented by WKR .

Journal

Journal of the Atmospheric Sciences – American Meteorological Society

Published: Apr 29, 2002

There are no references for this article.