Thursday, 11 January 2018: 2:15 PM
Room 17B (ACC) (Austin, Texas)
In this study, data collected by the Atmospheric Imaging Radar (AIR) is analyzed in conjunction with data from a local NEXRAD site (KFDR) for a tornado near Tipton, Oklahoma on 16 May 2015. Analysis is conducted via PPIs from both radars, polarimetric data from KFDR, time-height plots from the AIR, and a GBVTD analysis. This study is novel in that it uses high-resolution mobile radar data (update times of 6-7 s) in tandem with polarimetric data from NEXRAD in order to identify debris. Leveraging the high spatiotemporal resolution of the AIR with the polarimetric capability of NEXRAD leads to analysis of reflectivity distributions, debris lofting, and oscillations in tornado intensity during the mature stage of the tornado. Debris is found to be lofted in a concentric ring of increasing radius and height around the tornado over several minutes, while debris lofting and asymmetric reflectivity distribution around the weak echo hole are found to coincide with changes in vortex tilt on multiple occasions throughout the mature stage of the tornado. Hydrometeor fallout and a possible descending reflectivity core precede multiple internal momentum surges behind the rear-flank gust front. Additionally, GBVTD-derived radial convergence is used to show near-surface convergence intensification at the same time and location as when the debris ring is lofted. The results of this study are divided into two main sections: debris processes and vortex dynamics. In an effort to link these two sections, possible correlation between debris motion and kinematic changes in the vortex is noted.
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