Changes in mesoscale divergence structures based on storm evolution
Jordan Moore, Texas A&M University, College Station, TX; and A. Fanning, J. Stachnik, and C. Schumacher
The upscale effects of diabatic heating and mesoscale divergence from local precipitating systems upon the planetary circulation are poorly understood in the subtropics. More than twelve months of data collected from the S-band Aggie Doppler Radar (ADRAD) are examined to better elucidate the role of mesoscale divergence as related to storm evolution for a variety of storm types and background environments in southeast Texas. A simple classification scheme is used to denote whether a storm is in a developing, mature, dissipating, or decaying phase based upon reflectivity characteristics (including temporal and spatial evolution of the maximum reflectivity, echo top heights, and storm structure). In addition, the scheme identifies whether a storm contained primarily convective or stratiform elements.
Hourly-averaged divergence plots and corresponding velocity azimuth display (VAD) profiles derived from ADRAD velocity data are analyzed as a function of storm evolution for multiple events spanning the data collection period. Trends in the divergence structures (e.g., divergence magnitude, depth, and vertical juxtaposition of divergence/convergence layers) are presented throughout the lifetime of numerous storms, thus providing a preliminary estimate of how climatological divergence structures change with the temporal evolution of precipitating systems in this region.
Poster Session 1, Student Conference General Poster Session
Sunday, 20 January 2008, 5:30 PM-7:00 PM, Exhibit Hall B
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