Studies of phased-array scan strategies for radar data assimilation

Sponsored by multi-government agencies and especially by the US Navy, a phased-array weather radar has been constructed at NSSL Norman Oklahoma. This establishes the first National Weather Radar Testbed (NWRT) equipped with the solid-state phased-array antenna. One of the important and yet very challenging research goals at NWRT is to optimally design and utilize the electronically-controlled agile beam scans for various meteorological applications. This includes assimilating phased-array radar observations into mesoscale models to improve numerical analyses and predictions of severe storms and other hazardous weather conditions. This paper reports our research progress in this direction. In particular, theoretical and numerical studies are conducted to address the following important issues: (i) how to measure information content extracted from radar observations by a data assimilation system; (ii) how to compress radar data into super observations (super-obbing) to improve the assimilation efficiency and accuracy with an exiting radar scan strategy; and (iii) how to design phased-array scan strategies by taking the advantages of phased-array rapid and flexible scan capabilities to enhance radar observation information content for data assimilations. Theoretical analyses and practical solutions to these issues will be presented with numerical results at the conference.