Use Sophisticated Radar Reflectivity Extrapolation to Improve the Accuracy of the Nowcasting over Taiwan Area - Part Ii: Statistical Analysis

The purpose of the research is to build up and develop a sophisticated nowcasting system, but costs less computational resource. By using radar reflectivity from the network over Taiwan, with variational echo tracking technique and semi-Largrangian backward scheme﹐ the motion field of the weather system is able to obtain and extrapolate to the next time step for nowcasting. The advection based on the motion field is allowed for large-scale rotation, deformation, and differential motion between different systems. These features can better capture the displacement of the weather system. The main targets of the nowcasting system are strong convections with heavy precipitation such as Mei-Yu front, frontal system, south-west flow and thunderstorm. The performance of the nowcasting will be examined by using different skill scores (POD, FAR, CSI, and ETS). We expect to improve 0-3 h weather prediction, so that it is able to prevent disasters and reduce damages.