Updated mobile radar climatology of supercell tornado structures and dynamics
Curtis R. Alexander, Center for Severe Weather Research, Boulder, CO; and J. Wurman
High-resolution mobile radar observations of supercell tornadoes have been collected by the Doppler On Wheels (DOWs) platform between 1995 and present. The result of this ongoing effort is a large observational database spanning over 100 separate supercell tornadoes with a typical data resolution of O(50 m X 50 m X 50 m), updates every O(60 s) and measurements within 20 m of the surface.
Stemming from this database is a multi-tiered effort to characterize the structure and dynamics of the high wind speed environments in and near supercell tornadoes. To this end, a suite of algorithms is applied to the radar tornado observations for quality assurance along with detection, tracking and extraction of kinematic attributes.
The integration of observations across tornado cases in the database is providing an estimate of observed tornado size and intensity distributions that differ significantly from the damage surveyed distributions. Vertical structure of the tornadoes is examined to characterize differences between near-surface tornado wind speeds and those associated with the larger scale mesocyclonic flow aloft often observed by operational radars. The evolution of angular momentum and vorticity near the surface in many of the tornado cases is also providing some insight into possible modes of scale contraction for tornadogenesis and failure.
Extended Abstract (2.9M)
Session 19, High-resolution radar observations of supercells and tornadoes
Friday, 31 October 2008, 10:15 AM-11:45 AM, North & Center Ballroom
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