A 3-D variational method for single-Doppler velocity retrieval Applied to a Supercell Storm Case

In recent years, progress has been made on single-Doppler velocity retrieval and many retrieved methods have been developed and tested with idealized and real data case. A new scheme of 3-D variational single-Doppler velocity retrieval method was developed recently by Gao et al (1999). The method was tested in an idealized deep-convection storm case. It was shown that both horizontal wind and vertical velocity are well retrieved based on the test.

In this paper, the original method is improved and tested using May 11, 1981 Oklahoma supercell storm data set. It is very encouraging that the detailed structure of the storm is well retrieved comparing with the dual-Doppler analysis. In order to apply the result of single-Doppler velocity retrieval into a high-resolution numerical weather prediction model, such as ARPS, the retrieval fields should be defined on all regular grid points. To this end, a sounding is included in the variational retrieval method as a background. It is also shown that there is a smooth transition between the area where the data is provided by the radar observation and the area where it is only supplied by the wind observation of sounding.