RADAR QUANTITATIVE PRECIPITATION ESTIMATION TECHNIQUES AND EFFECT EVALUATION

This research work is aimed at improving the radar QPE(Quantitative Precipitation Estimation)techniques.Based on CINRAD/SA dataset of volume scan reflectivity and rain gauge data in the Guangdong area,the probability-fitting technique(PFT),which is adopted to localize the relationship between Z and I,and the OI(Optimum Interpolation) method,which is used to correct the radar precipitation estimation,have been used.In order to estimate large scale precipitation,multi-radar QPE was combined by weighting each radar by square multiplicative inverse(iω==1/RMSE(K)2/n∑i-1/RMSE(i)2)of its RMSE(root mean square error).Error statistical analyses indicated that station gauge rain is most closely related to the average of nine point’s reflectivity above.Additionally,it was verified that the QPE precision of each single-Doppler radar with the same model is different;As for the multi-radar QPE,the result of OI combination of corrected value of single-radar precipitation estimation is better than that of OI combination of single-radar precipitation estimation.Trough cross-validation,some conclusions were obtained that the OI correction method can minimize the precipitation estimation errors to a certain extent and correcting single radar precipitation estimation in advance is important.It was also shown that the method of multi-radar QPE combination is better than gauge’s OI.Against the radar composite image hybrid reflectivity QPE,the precision of the former is higher than the latter.So,multi-radar QPE combination techniques have some reference value for application of radar data and have application prospective in operational weather services.