17.4 Exploring the Differences in Deep Convective Transport Characteristics amongst Thunderstorm Regimes Using Seasonal WRF Simulations

Friday, 9 August 2013: 2:15 PM
Multnomah (DoubleTree by Hilton Portland)
Brandon C. Bigelbach, University of North Dakota, Grand Forks, ND; and G. L. Mullendore, M. Starzec, and S. T. Jorgenson

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 both convection-resolving scale (2 km) and at a scale requiring convective parameterization (18 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 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. Storm and environmental characteristics that explain these differences will be discussed.

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