辽宁地区暖区和锋面暴雨个例对比分析

Comparative analysis of warm area and frontal heavy rain systems in Liaoning province

2013年7月1—2日,辽宁地区出现了持续时间较长的暴雨天气过程,此次过程可以分为3个阶段,其中包括两次暖区降水和一次冷锋锋面与暖区降水共存的过程,第一阶段的暖区降水和第三阶段的锋面降水形成了西北雨带,第二阶段的暖区降水形成了东南雨带。利用NCEP再分析资料、常规自动站观测资料、加密自动站观测资料和卫星资料,详细分析了此次过程中各阶段降水产生的机制以及锋面降水和暖区降水的主要物理差异。结果表明:暖区强降水主要出现在干线冷湿气团一侧或地面辐合线附近,并且由于暖区高温、高湿的特点,其产生的降水通常比锋面附近强,同时暖区降水与锋面降水在触发机制、中尺度环境条件、动力、热力结构等方面也存在着差异。

A rainstorm process with long duration occurred in Liaoning province during 1--2 July, 2013, which can be divided into three stages, including two warm area precipitation cases and a frontal and warm area precipitation coexistence case. The northwest rain band is formed by the warm area precipitation in stage one and the frontal precipitation in stage three, while the southeast rain band is formed by the warm area precipitation in stage two.Based on the NCEP/NCAR reanalysis data, the conventional automatic weather station data, the intensive automatic station data and the satellite data, the generation mechanism of each precipitation and the main physical difference between the generating process of frontal precipitation and the warm area precipitation were analyzed in detail.Results show that warm area heavy rain mainly occurs at the cold wet side of dry line or near surface convergence line, and since the characteristics of high temperature and humidity in warm area, the precipitation in this area is generally stronger than that in the nearby frontal area. In addition, there are many differences between warm area precipitation and frontal precipitation in triggering mechanism, mesoscale environmental conditions, dynamic and thermal structures.