闽中北前汛期多普勒雷达定量估测降水分析

Analysis of Quantitative Precipitation Estimation Based on Doppler Radar Data in Pre-rainy Season in Northern and Central Fujian

使用2002、2003年福建中北部27个气象站5—6月自记雨量资料及相应的雷达体扫资料,通过用最优化法统计得出不同区域的Z-I关系,并将统计结果用于2005年5—6月的降水估测。同时利用实时雨量资料采用卡尔曼最优(卡尔曼滤波+最优插值)、变分等估测方法对2005年几次混合型降水过程进行实时雨量校正,用福建北部武夷山九曲溪流域雨量计检验校正后的雨量值,并对上述几种方法的测量精度进行比较、分析。结果表明:卡尔曼最优、变分法及100km距离范围内的最优化法的过程平均相对误差小于25%,100km距离范围以外最优化法的过程平均相对误差明显增大,Z=300I1·4估测的误差最大。

Based on the Doppler radar data and the data from twenty-seven automatic weather stations from May to June in 2002 and 2003 in the northern and central Fujian, the statistical analysis of optimization is made to obtain the Z-I relation of different regions. The rainfall amounts in precipitation processes in 2005 are estimated. Using variational method andoptimum Kalman filter method （combine Kalman Filter with optimum interpolation）, radar estimations are tested with rainfall data of Wuyishan Jiuquxi Valley in the northern Fujian. The accuracies for the methods are compared and analyzed. The results show that mean relative errors are less than 25% with variational method and optimum Kalman Filter method, it is also less than 25 % from 0 to 100km with optimization method, however, it increase remarkably from 100 to 200km. Mean relative error is the greatest with the relation of Z=300ITM.