Numerical Experiments on Retrieving the Three-Dimensional Wind Field of a Strong Convective Storm from Dual-Doppler Radar

A simple technique of retrieving three-dimensional wind fields is investigated from the dual-Doppler weather radar radial wind based on certain assumptions.The result provides all of the three wind components,and satisfies both the radial velocity equation system and the continuity equation.The strong convective storm that occurred on 29 June 1996 in the northeast of Beijing is chosen as the retrieving case and the errors are analyzed.Retrieved wind fields from the simulated radar data show that the general trends of the retrieved wind stream field are coincided very well with the simulated ones.The central positions are generally at the same altitude and the updraft as well as downdraft structures are almost the same.Analyses of average deviation,average squared error and relative deviation of the horizontal velocity,show that the errors are all very small,therefore,the retrieved wind field can reflect the real three-dimensional one by and large.At the same time,the average deviation of vertical velocity shows that it is very small on various heights,indicating that the retrieved results are satisfactory while the results of 27min are even better than 36min.The discrepancy might result from that the storm is at its robust phase with the strongest convective activity at 36min,while at 27min the cloud is at development stage with relative weaker convective activity.Since the retrieving results,especially the vertical velocity results are good enough to reflect real situations of three dimensional wind field and the results are much better at 5.5km height while the centers of mesoscale convective systems are at about 4—6km altitude,so the retrieving algorithm can be developed and utilized in future research works.