15B.7
High resolution assimilation of CASA and NEXRAD radar data in near-real time: Results from Spring 2007 and plans for Spring of 2008
Keith A. Brewster, CAPS/Univ. of Oklahoma, Norman, OK; and J. Brotzge, K. W. Thomas, Y. Wang, M. Xue, J. Gao, D. Weber, and K. Howe
Recently a network of four X-band radars was deployed in southwestern Oklahoma by the Center for Adaptive Sensing of the Atmosphere (CASA). CAPS developed a system to assimilate reflectivity data from the CASA radars, along with NEXRAD, mesonet, satellite and conventional data at 1-km grid resolution using ADAS and Incremental Analysis Updating (IAU) in the ARPS non-hydrostatic forecast model. Four 6-hour forecasts were made using various combinations of these data for each event day during the Spring of 2007. These forecasts were run in near-real time, a pair of 6-hour forecasts taking 8 hours using a local cluster of Pentium4 Linux computers. Additional forecasts were made later utilizing the radial velocity data in ADAS. Sample forecast results and comparison verifications of these forecasts will be shown. For 2008 we have been challenged to run the assimilation and forecasts in real-time and to employ the ARPS 3DVAR on the Linux cluster. The design of that assimilation and forecast system and progress toward its implementation will be discussed. Figure 1. Sample forecast from 09 May 2007 using radar reflectivity and radial velocity data from the CASA and NEXRAD radars. 3-hour forecast of reflectivity (dBZ, color shaded) and vertical vorticity at ~600 m AGL compared to verification track of radar circulations (triangles) during the period (03-04 UTC).
Session 15B, Results from Recent Field Experiments and Their Potential Relevance to Operational Prediction
Thursday, 24 January 2008, 1:30 PM-3:15 PM, 205
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