15.5 Mobile radar based climatology of tornado structure and dynamics

Thursday, 9 November 2006: 5:45 PM
St. Louis AB (Adam's Mark Hotel)
Curtis R. Alexander, Center for Severe Weather Research, Boulder, CO; and J. Wurman

Efforts to collect mobile radar observations of tornadoes from the Doppler On Wheels (DOWs) over the past decade during both the VORTEX and ROTATE field projects have yielded a large dataset covering about 100 tornadoes with observed Doppler velocities as high as 135 m s-1. Typical resolution in tornadoes from this dataset is on the order of 50 m X 50 m X 50 m (sometimes as fine as 12 m x 3 m x 3 m) with 30 to 60 s updates and observations usually extending below 100 m AGL and up to 3-5 km AGL. Therefore, it is now possible to construct a tornado climatology based upon high resolution radar observations of actual tornado structure. Conclusions are drawn about the relationship between tornado structure and the amount of precipitation surrounding the tornado circulation, the tendency for tornado formation to occur simultaneously through a deep layer as opposed to building-down from aloft, and scale separation of observed concentric circulations near the surface.
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