19A.3 High-resolution EnKF assimilation of tornado-scale radar observations for a tornadic supercell: preliminary results

Friday, 30 September 2011: 11:00 AM
Monongahela Room (William Penn Hotel)
Robin L. Tanamachi, CAPS/Univ. of Oklahoma, Norman, OK; and M. Xue, H. B. Bluestein, K. Orzel, S. J. Frasier, and M. I. Biggerstaff

The VORTEX2 project provided unprecedented radar coverage of several tornadic supercells, including at least two in which W-band radar reflectivity and Doppler velocity data, with a radial resolution of 30 m and an average update time of 18 sec, were collected on tornadoes. These W-band radar data are assimilated into very high resolution (≤ 50 m horizontal grid spacing), Advanced Regional Prediction System (ARPS) analyses of the parent supercell storm using the EnKF technique. Data from nearby WSR-88Ds and storm-scale SMART-Rs are used to establish the storm-scale features of the storm while the W-band Doppler velocity data are assimilated to establish the tornado-vortex scale features near the surface. The impact of assimilating such high-resolution, near-surface wind data into the analyses will be assessed via a combination of RMS error statistics and subjective tracking of supercell features (e.g., rear flank gust fronts, vortex position/strength at different altitudes). To the best knowledge of the authors, this should be the first time such high-resolution radar observations of tornadoes, including tornadogenesis processes, are assimilated into a NWP model.
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