Date of Award

January 2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Atmospheric Sciences

First Advisor

Gretchen L. Mullendore

Abstract

Convective mass transport is the transport of mass from near the surface up to the upper troposphere and lower stratosphere (UTLS) by a deep convective updraft. This transport can alter the chemical makeup and water vapor balance of the UTLS, which can affect cloud formation and the radiative properties of the atmosphere. It is therefore important to understand the exact altitudes at which mass is detrained from convection. The purpose of this study is to improve upon previously published methodologies for estimating the level of maximum detrainment (LMD) within convection using data from individual radars. Three methods were used to identify the LMD and validated against dual-Doppler derived vertical mass divergence fields. The best method for locating the LMD was determined to be the method that uses a horizontal reflectivity texture-based technique to determine convective cores and a multi-layer echo identification to determine anvil locations.

The methodology was found to work in many but not all cases. The methodology works best when applied to convective systems with mature updrafts, and is most accurate with convective lines and isolated cells. A time lag is present in the reflectivity based LMD compared to the vertical mass divergence based LMD because the reflectivity method is dependent on anvil growth.

This methodology was then applied to archived NEXRAD 3D mosaic radar data. The regions of analysis were chosen to coincide with the observation regions for the Deep Convective Clouds and Chemistry Experiment (DC3): the Colorado Foothills, Southern Plains (OK/TX), and Southeast US (AL). These three regions provide a wide variety of convection. The dates analyzed were from May and June of 2012 so the results can be compared to future DC3 studies

Download

Share

COinS