改进后TREC外推方法在台风临近降雨预报中的应用

本文提出了一种改进后的COTREC方法(CLTREC)。在传统COTREC方法基础上,增加了相邻时刻回波强度连续约束检验和矢量全变分修正,从而使得反演的雷达回波移动矢量场更为连续。选取了3个登陆台风个例,对方法进行检验。结果表明,CLTREC方法比传统COTREC方法的外推移动矢量场更平滑,台风环流特征也更合理。基于CLTREC外推预报的降水形状、强度和位置都与观测更为接近,1 h的台风定量降雨预报与观测相关系数达0.7以上。总体而言,相比传统的COTREC方法,CLTREC方法改善了台风短时临近降雨预报精度。

The improved TREC algorithm and its application to the precipitation now-casting for landfall typhoon

In this study, a Continuity of Laplace TREC vectors (CLTREC) algorithm based on traditional COTREC was proposed. The new algorithm adds two improvements:(1) the echo continuity constraint conditions; (2) the total variation reconstruction of motion vectors. Three typhoon landfall cases were selected to verify the new method. The evaluation results show that the quality of the extrapolated motion vector field obtained by CLTREC is better and more continuous than that by COTREC and the characteristics of typhoon circulation is more reasonable. The rainfall field obtained by CLTREC is much closer to the actual rainfall spatial distribution and strength characteristics. The improvement effect of one hours is the most obvious,whose correlation coefficient up to more than 0.7. Overall, compared with the traditional COTREC algorithm, the CLTREC algorithm can improve the accuracy of the typhoon precipitation nowcasting.