Mobile, phased-array, Doppler radar observations of tornadoes at X band

From 2009-2011, a mobile, phased-array, X-band Doppler radar (the MWR-05XP) was used to obtain several datasets of tornadic supercells. The MWR-05XP scans electronically in elevation while the antenna scans mechanically in azimuth so that, at a given azimuth, data at all elevation angles are being obtained at almost the same time. As a result, data collected by the MWR-05XP can be used to investigate the short time scale, vertical evolution of tornadoes without correcting for storm motion or invoking steady state assumptions. On 5 June 2009, during year one of VORTEX2, the MWR-05XP scanned a supercell in Goshen County, WY during the entirety of a tornado. Volume scans up to 20° in elevation angle were obtained every ~7 sec. In addition, the MWR-05XP scanned the dissipation phase of a tornado on 19 May 2010, during year two of VORTEX2, near Kingfisher, OK. Also, on 24 May 2011, data of a violent tornado near El Reno, OK were obtained shortly after it formed. In the latter two datasets, volume scans up to 40° in elevation angle were collected every ~6-15 sec. As a result, thousands of observations of TVS signatures up to storm midlevels were obtained in the three datasets. The focus of the talk will be on the time-height evolution of the TVS signatures. Specifically, topics of discussion will include: 1) changes in TVS intensity, including observations of a possible height-dependent tornado dissipation and secondary genesis, 2) the vertical orientation of the tornadoes, and 3) the process of tornado decay.