Extended Abstract

level reached the highest record since the founding of People's Republic ofChina in 1949, which was caused by heavy precipitation events frequentlyoccurred from June to October 2003. In this study, three heavy precipitationevents, listed in Table 2, were used to investigate the quantitative precipitationestimation from radar data.Table 2 Heavy precipitation events occurred in Huaihe regions in 2003CasesLast Time (hour)0000 BJT 29 June to 2300 BJT 3 July 1200000 BJT 4 July to 2300 BJT 7 July 960000 BJT 8 July to 2300 BJT 11 July 96Table 3 The CC and RMSE derived from the radar obtained QPE usingZ-Is for the stratiform , convective, and mixture of stratiform and convectiverespectively with and without rain gauge calibration for the cases in 2003CasesNo Gauge Calibration Gauge CalibrationZ-I(No. used)CC RMSE CC RMSE0000 BJT 29June to 2300 BJT3 July (534)0000 BJT 4 Julyto 2300 BJT 7July (189)0000 BJT 8 Julyto 2300 BJT 11July 2 (814)Z=200R 1.6 0.85 3.88 0.96 1.48Z=300R 1.4 0.85 3.88 0.95 1.59MCS 0.84 3.72 0.97 1.29Z=200R 1.6 0.91 7.86 0.99 1.77Z=300R 1.4 0.90 7.08 0.99 2.02MCS 0.90 7.01 0.99 1.67Z=200R 1.6 0.76 4.13 0.98 1.09Z=300R 1.4 0.76 4.17 0.97 1.26MCS 0.76 4.02 0.98 1.07In order to achieve the better QPE, Z=200R 1.6 and Z=300R 1.4 were used toestimate precipitation for stratiform and convective respectively identified byFNN technique described in the previous section, which is named mixture forconvective and stratiform (MCS) in this paper. Z=200R 1.6 and Z=300R 1.4 werealso applied to the QPE for the comparison with the MCS. The calibrationalgorithms using hourly rain gauge data were also applied to aboveinvestigations. Table 3 summarizes these investigations.From Table 3, it can be seen that the CC and RMSE significantly vary fromcase to case for the QPE algorithms without calibration. And the threealgorithms nearly achieve the same CC but the MCS has the smallest RMSE.The MSC only obtains slightly better results than other algorithms, which maysuggest two Z-I relations selected cannot represent actual Z-I relations. Thesimilar results can also be observed for the calibration algorithms. However, itcan be seen that the calibration algorithms achieve much better scores thanthe algorithms without calibration. These arise from the fact that the same raingauge data were used for both calibration and validation in this study.Therefore, the better scores shown only indicate the improved upper limits for4-140-