Wednesday, 25 January 2012: 4:30 PM
Rapid-Scan, X-Band, Mobile Doppler Radar Measurements of An EF-5 Tornado in Oklahoma on 24 May 2011
Room 252/253 (New Orleans Convention Center )
During a major tornado outbreak on 24 May 2011, two rapid-scan, mobile, X-band Doppler radars coordinated by participants from the School of Meteorology at the University of Oklahoma (OU) in Norman, collected an unprecedented dataset in an EF-5 tornado as it formed and moved by us from a location southwest of El Reno, OK. RaXPol (Rapid X-band Polarimetric Radar), a polarimetric, mechanically scanning radar built by ProSensing and based at OU, having a half-power beamwidth of 1 deg and making use of frequency hopping to increase the number of independent samples, collected data for almost an hour, including volumetric scans every 2 deg from 2 deg to 17/18 deg elevation angle every 18 seconds, and when the tornado was at close range, 1 deg elevation scans once every two seconds for about six minutes. The MWR-05XP (Meteorological Weather Radar 2005 X-band, phased-array), a phased-array radar from the Naval Postgraduate School, having a half-power beamwidth of 1.8 deg in azimuth and 2 deg in elevation, also making use of frequency hopping, collected data from two other locations, at one for almost an hour, including volumetric scans from 1 deg to 40 deg elevation angle, in increments of 1.5 deg, every 11 seconds during the first deployment and every 7 - 8 seconds during the second. For a short period of time, dual-Doppler analysis using data from both radars is possible.
In this presentation we will show samples of the data collected, including very-high temporal resolution views of the multiple-vortex/single vortex tornado, which was as close as ~ 3 km from one of the radars. Polarimetric debris signatures, miso-vortices along a weak-echo band that wrapped around the tornado, and other features will be shown, in addition to videos of the tornado and photographs from our damage survey the day after the tornado.