青海一次强降水过程的物理量预报应用试验

Application Test of Physical Quantities in a Severe Precipitation Forecast in Qinghai

针对强降水业务预报工作的实际需求,利用常规观测站和区域自动站逐小时降水资料及欧洲中心(ECMWF)细网格数值预报产品,采用水平螺旋度、水汽通量及水汽通量散度对2017年7月26—27日发生在青海省的强降水天气过程进行预报应用分析。结果表明:水平螺旋度、水汽通量及水汽通量散度与降水的发生发展和强降水中心有较好的对应关系;500 h Pa正水平螺旋度强度对降水强度的变化有一定的指示性,负水平螺旋度强度偏强时可以很好地指示强降水中心位置;水汽通量大值区内水汽辐合强度越强,降水强度也越强。

For the demand in heavy rainfall forecasting,based on the hourly precipitation data of the conventional and automatic stations,high resolution prediction field data of ECMWF,the severe precipitation occurring in Qinghai from 26 to 27 on July 2017 was analyzed by using physical quantities such as horizontal helicity,water vapor flux and vapor flux divergence for the forecast application.The results show that the distribution of horizontal helicity,water vapor flux and vapor flux divergence had a good corresponding relationship between the occurrence and development of precipitation and the heavy rainfall center. The intensity of positive horizontal helicity on 500 h Pa had a certain indicator to the change of precipitation intensity. The intensity of negative horizontal helicity could give good indicator to the location of heavy rainfall center when it was stronger. In large value area of water vapor flux the stronger the water vapor convergence intensity was,the stronger the precipitation intensity.