Evolution of Area-Averaged Vertical Velocity in the Convective Region of a Midlatitude Squall Line
Abstract
The evolution of area-averaged vertical velocity over a 50 km length segment of the convective region of the 10 - 11 June 1985 squall line system observed during PRESTORM (Preliminary Regional Experiment for Stormscale Operational and Research Meteorology - Central Phase) was examined over a period of 43 minutes during the storm's mature stage. Seven dual-Doppler analyses with a temporal resolution of 6 - 10 minutes were used to determine vertical velocity. The vertical velocity was then sampled within the boundaries of an objectively defined convective region; delineated by low and mid-level thresholds of reflectivity and reflectivity gradient. Variations in area- averaged vertical velocity profiles suggested significant mesoscale evolution of the convective region over the period of analysis. This notion was supported by examination of area-averaged reflectivity profiles, and the distribution of vertical velocity magnitudes as a function of height, as well as cross-sections of vertical velocity, reflectivity, and storm-relative flow fields. Comparison of the observed changes in the convective drafts, reflectivity structure, and storm-relative flow, with those of numerical simulations of squall line evolution suggested that the convective region had undergone a rather quick transition from a stronger, developing state to a much weaker, mature state
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1992
- Accession Number
- ADA265333
Entities
People
- Dennis A. Hobson
Organizations
- Air Force Institute of Technology