一次连续性暴雨天气过程的分阶段对比分析

A Phased Comparative Analysis of a Continuous Rainstorm Weather Process

文章利用地面自动站、天气雷达等探测资料和ERA5逐小时再分析资料,对福建漳州一次连续性暴雨过程分阶段分析发现,该过程中三种性质不同的降水表现出的温湿场和不稳定性等方面存在明显差异。第一阶段降水对流性最强,属切变南侧高温高湿环境下的暖区暴雨,有强的对流不稳定,假相当位温场(θse)的水平和垂直分布均存在高能舌,强降水区域存在更为明显的上升运动和水汽辐合,并伴随列车效应;第二阶段对流不稳定有所减弱,为锋区南压导致的系统性降水,并存在和锋区相对应的密集θse等值线;第三阶段则为低涡东侧暖切造成的大范围层云降水,层结稳定,水汽、热力和动力条件较弱且配合较差。模式检验表明CMA-3KM数值预报在此次过程中表现最好,主观预报对暖区对流降水的预报准确率较低,但对锋面等系统性降水具有一定订正能力。

Using the detection data of ground automatic station, weather radar and ERA5 hourly reanalysis data, this paper analyzes a continuous rainstorm process in Zhangzhou, Fujian province in stages. It is found that there are obvious differences in temperature and humidity field and instability of three kinds of precipitation with different properties in this process. In the first stage, the precipitation had the strongest convective character, which was a warm rainstorm in the high temperature and high humidity environment in the south side of shear, with strong convective instability. The horizontal and vertical distribution of pseudoequivalent potential temperature field(θse) had high-energy tongue, and the upward movement and moisture convergence were more obvious in the heavy precipitation region,accompanied by train effect. In the second stage, the convective instability was weakened, and the precipitation was caused by the southern pressure of the front area, and there were dense θse isolines corresponding to the front area. The third stage is large-scale stratus precipitation caused by the warm cutting of the east side of the vortex. The stratification is stable, and the water vapor, thermal and dynamic conditions are weak and poorly coordinated. The model test shows that CMA-3KM numerical prediction performs best in this process. The accuracy of subjective prediction for convective precipitation in warm area is low, but it has a certain correction ability for frontal and other systematic precipitation.