Application of Doppler Radar Wind Field Retrieval Technique to Southwest Vortex Rainstorm Process
Horizontal wind fields in different heights were retrieved for two local severe rainfall processes within the southwest vortexes which occurred in Chongqing in 2010 and 2013, respectively, using Doppler weather radar 4DVar (four dimensional variation) assimilation technique. Local circulation patterns which are prone to local intense rainfalls are also analyzed. The results show that the position and evolution of low level jet streams, low level convergence lines and local cyclonic vortices can be accurately denoted by retrieved wind fields. The evolution of convergence lines and the intensity and transfer of low level jet streams are indicative of heavy precipitation. The deeper the local cyclonic vortex is, the greater the intensity and extension of local intense rainfall become. Coupling in cyclonic vortexes of different heights can be prone to intensification of low level jet stream and transportation of moisture.