一次局地强降水的中尺度特征

Mesoscale Characteristics of a Local Rainfall

利用常规资料和ERA5再分析资料对2020年7月8日黑龙江省出现的一次局地强降水进行了中尺度特征分析。结果表明:该过程是由于暖区内低层暖平流强迫发生的,具有局地性强,降水强度大的特点;深厚的湿层和弱的垂直风切变为此次强降水提供有利的环境条件;超低空西南急流和中层干入侵造成的对流性不稳定促进的局地强降水的发生;在地面辐合线的触发下,高垂直液体含水量值的维持在雷达特征上形成了后向传播的“列车效应”。

The mesoscale characteristics of a local heavy precipitation in Heilongjiang province on July 8, 2020 are analyzed by using conventional data and ERA5 reanalysis data. The results show that: this process is due to the forcing of warm advection at the lower level in the warm region, which is characterized by strong local character and high precipitation intensity. The deep wet layer and weak vertical wind shear provided favorable environmental conditions for the heavy rainfall. Local heavy rainfall was promoted by convective instability caused by ultra-low southwest jet and middle-level dry intrusion. Under the trigger of ground convergence line, the maintenance of high vertical liquid moisture content results in the “train effect”of backward propagation on radar characteristics.