Wednesday, 14 January 2009
Reexamining convective/stratiform classification of TRMM ground validation radar data
Hall 5 (Phoenix Convention Center)
Since the inception of the Tropical Rainfall Measuring Mission (TRMM), the operational algorithm for convective/stratiform classification of ground validation (GV) radar data has been the Steiner et al. (1995) procedure. This approach relies solely on horizontal reflectivity gradients and peakedness criteria to arrive at a determination of rainfall type. Over the past decade, researchers have investigated various methods of incorporating radar data in the vertical to account for the potential influence of the bright band, an enhanced reflectivity signature associated with the melting level. In this study, the Biggerstaff and Listemaa (2000) algorithm, which addresses vertical as well as horizontal reflectivity gradients along with the extent of bright band influence, is applied to radar data from the Houston, Texas and Melbourne, Florida GV sites. The work utilizes reflectivity data interpolated to a finer 0.5 km vertical resolution required by the algorithm, three times the vertical resolution of the current operational product. Shorter range studies are performed for the more unique meteorological events to highlight distinctions between the two approaches. On broader temporal scales, the impacts of algorithm modification on classification fraction and rain volume are explored as well as potential uncertainties in rainfall estimation crucial to numerous hydrological applications.
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