Extended Abstract (296K)8.3
Multi-Doppler Radar Analysis of a Tornadic Thunderstorm using a 3D Variational Data Assimilation Technique and ARPS model
Edward J. Natenberg, University of Oklahoma, Norman, OK; and J. Gao
A three dimensional variational (3DVAR) assimilation technique has been developed at the Center for Analysis and Prediction of Storms (CAPS) to produce the initial conditions for the Advanced Regional Prediction System (ARPS) storm scale NWP model. In this study, this technique is used to analyze the May 8th 2003 Moore/Midwest City, Oklahoma supercell thunderstorm. This storm produced an F-4 tornado that tracked 19 miles across central Oklahoma. Three 88D radars (KFDR, KINX and KVNX) within Oklahoma observed the upper-level part of the storm. The other three radars (one TDWR, one dual-polarization radar, KOUN, and another 88D radar, KTLX) are in close proximity to the storm, thus capture the low level structure of the storm. Together with the ARPS NWP model, a high-frequency intermittent data analysis and assimilation are performed using the data from these six radars. The operational ETA, along with surface and upper air observations will be used to give a complete picture of the storm environment. The initial analysis captures a well-defined mesocyclone in the mid levels and the wind circulation associated with a hook-shaped echo. It is shown that the storm circulation, including the strong updraft and associated downdrafts, is well analyzed in this case. The analysis also provides thermodynamic and hydrometeor related fields through interacting with the ARPS model. A detailed analysis will be presented at the conference.
Session 8, Mesoscale Data Assimilation
Tuesday, 22 January 2008, 3:30 PM-5:30 PM, 204
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