对流云人工增雨效果检验技术方法及应用

对流云降水时空变差较大,利用WoodleyRosenfeld提出的建立在雷达资料基础上的移动目标单元法对对流云增雨作业进行效果评估。利用塘沽、北京及秦皇岛3部雷达资料,对其进行插值处理,确定移动目标单元识别和跟踪方法,然后在移动目标单元中确定催化单元和对比单元,记录每个单元的物理参量,利用Z-R关系反演降水量,对物理参量和反演降水量做统计分析,定量计算增雨效果的同时提供人工增雨的物理证据。应用该方法对2011年7月24日对流云人工增雨作业效果进行评估,结果表明:催化剂进入云中后使得最大回波强度增强,回波顶高增加,从物理角度证明了催化对增加降水起到了一定作用。利用降雨率对增雨作业进行定量效果分析,结果表明该次作业相对增雨7.69%,显著度检验值0.043,增雨效果较为显著。

A Method for Evaluating Effectiveness of Convective Cloud Precipitation Enhancement and Its Application

The reliability of convective cloud seeding effectiveness evaluation result is poor when using traditional statistical test method because of larger spatial and temporal variation. The floating target area method, a new method proposed by Woodley, is introduced, which is based on radar echoes. Some modifications are made in this scheme in combination with Tianjin geography and weather modification operation characteristics. The radar base data are used to determine the floating target cell recognition and tracking methods, then determine the catalytic units and control units in the floating target cells; the physical parameters and the retrieved precipitation of each unit are recorded, and the precipitation enhancement effect is calculated to provide physical evidences of artificial rainfall. The method is used to evaluate the effectiveness of convective cloud seeding on 24 July 2011 in Tianjin, for example, and the objective evaluation results are obtained, which shows that: the value of the maximum echo intensity and echo top height increased as the catalyst got into the clouds. It is proved that artificial catalysis takes effect in precipitation enhancement. The effectiveness of precipitation enhancement is 7.69% at a significance of 0.043.