漳州市一次梅雨期强降水过程成因分析

Analysis of the Causes of a Heavy Precipitation Process during the Rainy Season in Zhangzhou City

利用常规观测资料对2020年5月19日发生在漳州市梅雨期一次强降水过程进行分析,得出此次过程是由近地层辐合线主导的局地性强降水,前期强盛的低空急流源源不断地提供较丰富的湿静力能量,辐合线的存在造成浅薄冷暖空气交汇,触发不稳定能量释放和强降水的发生。通过雷达分析得出此次过程属于典型的低质心热带海洋性降水回波,后向传播机制是导致回波在漳浦县维持较长时间的主要原因,双偏振雷达资料表明该回波以大雨滴为主,用于雨强估测效果较好。CMA-上海模式对弱天气尺度强迫的对流性强降水有一定的体现作用,在主观预报难以判断此类强降水时,加强潜势分析和回波监测是增加短时临近预报提前量的有效应对手段。

Using conventional observation data, an analysis is conducted on a heavy precipitation process that occurred during the rainy season in Zhangzhou city on May 19, 2020. It is concluded that this process is a localized heavy precipitation dominated by the convergence line of the near surface layer. The strong low altitude jet in the early stage continuously provides abundant wet static energy, and the existence of the convergence line causes the intersection of shallow cold and warm air, triggering the release of unstable energy and the occurrence of heavy precipitation. Through radar analysis, it is concluded that this process belongs to a typical low centroid tropical oceanic precipitation echo, and the backward propagation mechanism is the main reason for the echo to maintain for a long time in Zhangpu county. Dual polarization radar data shows that the echo is mainly composed of large raindrops, which has a good effect in estimating rainfall intensity. The CMA-Shanghai model has a certain manifestation effect on convective heavy precipitation forced by weak weather scales. When subjective forecasting is difficult to determine such heavy precipitation, strengthening potential analysis and echo monitoring is an effective response method to increase the short-term approaching forecast advance.