A Sub-Cloud Layer Vorticity Budget Analysis for Two Microburst-Producing Storms from Jaws Dual-Doppler Data
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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A vorticity component and budget analysis in three-dimensions is conducted for the subcloud layer of two microburst-producing storms using dual- Doppler derived winds. This research examines the vorticity associated with a single microburst-producing storm which occurred on 14 July 1982 and a multiple microburst-producing storm which occurred on 5 August 1982. The calculated vorticity data are examined over the storm domain 10 km x 10 km for the 14 July case and 15 km x 15 km for the 5 August case and the microburst domain 5 km x 5 km including two analysis times for the first case and three for the latter case. Results indicate that horizontal vorticity centers are coincident with strong horizontal gradients of vertical velocity and with areas of strong vertical shear. A vorticity budget analysis of the advection, divergence, and tilting terms, comprising the vorticity component equations, shows the magnitude of these terms to be greater in the microburst domain than in the storm domain. The difference in storm structure allow examination of the vorticity of a simple, nearly circular-symmetric microburst and that of a microburst within a complicated flow field. This leads to different vorticity distributions and budgets. Theses.