Date of Award

January 2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Atmospheric Sciences

First Advisor

Gretchen Mullendore

Abstract

It has been shown in several previous studies that there is a relationship between mesoscale storm type and deep convective mass transport characteristics. For example, a previous simulation study showed that a supercell storm transported significantly more

tracers into the stratosphere than did a multicell storm in an environment with identical thermodynamic structure. We utilize the Weather Research and Forecasting (WRF) model (version 3.2.1) with chemistry to simulate mass transport during the convective season of 2007 in the U.S. Southern Great Plains at convection-resolving scale (2 km). The storms that were resolved in the model were then classified using an object-based classification scheme. This classification scheme, which is based on schemes used in the

mesoscale observational community, uses model-derived radar reflectivity (a function of precipitation hydrometeors) to classify storm type as either weak convection, quasi-isolated strong convection (QISC), mesoscale convective system (MCS), or linear MCS.

This study focuses on examining the differences between the QISC and MCS regimes. Differences on the domain-scale are determined by investigation of two transport parameters: the level of maximum detrainment (LMD) and the magnitude of newly transport mass. Based on total transport over the entire region, results have shown

that there are some significant differences between regimes. The LMD is significantly higher in the MCS regime than in the QISC regime in July, but the LMD is very similar in the two regimes in May. Conversely, the magnitude of newly transported mass in the MCS and QISC is very similar in July, but significantly different in May. At a per storm scale, differences were determined by analysis of the magnitude of transport per deeply convective object and the LMD relative to the height of the tropopause. The tropopause-relative

LMD followed the domain-wide results, where there were significant differences in July but the regimes transported to similar altitudes in May. There were significant differences in the magnitude of transport per deeply convective object for both May and July.

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