The effect of mesoscale heterogeneity on the genesis and structure of mesovortices within quasi-linear convective systems

Dustan M. Wheatley, Robert J. Trapp

Research output: Contribution to journalArticlepeer-review

Abstract

This study examines the structure and evolution of quasi-linear convective systems (QLCSs) within complex mesoscale environments. Convective outflows and other mesoscale features appear to affect the rotational characteristics and associated dynamics of these systems. Thus, real-data numerical simulations of two QLCS events have been performed to (i) identify and characterize the various ambient mesoscale features that modify the structure and evolution of simulated QLCSs; and then to (ii) determine the nature of interaction of such features with the systems, with an emphasis on the genesis and evolution of low-level mesovortices. Significant low-level mesovortices develop in both simulated QLCSs as a consequence of mechanisms internal to the system - consistent with idealized numerical simulations of mesovortex-bearing QLCSs - and not as an effect of system interaction with external heterogeneity. However, meso-γ-scale (order of 10 km) heterogeneity in the form of a convective outflow boundary is sufficient to affect mesovortex strength, as air parcels populating the vortex region encounter enhanced convergence at the point of QLCS - boundary interaction. Moreover, meso-β-scale (order of 100 km) heterogeneity in the form of interacting air masses provides for along-line variations in the distributions of low- to midlevel vertical wind shear and convective available potential energy. The subsequent impact on updraft strength/ tilt has implications on the vortex stretching experienced by leading-edge mesovortices.

Original languageEnglish (US)
Pages (from-to)4220-4241
Number of pages22
JournalMonthly Weather Review
Volume136
Issue number11
DOIs
StatePublished - 2008
Externally publishedYes

ASJC Scopus subject areas

  • Atmospheric Science

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