一次高原切变线过程的雷达回波特征研究

Research on Radar Echo Characteristics of a Plateau Shear Line Process

摘要: 基于C波段新一代天气雷达资料，本文重点对西藏那曲地区的一次切变线降水过程进行了研究。结合降水特点，将此次过程分为了三个阶段，并对每个阶段的雷达回波特征以及降水演变过程进行了分析，结果发现：在瞬时强降水阶段，那曲地区雷达回波主要表现为对流较强的积、层混合云，且在降水强度最大时刻出现了较为明显的“牛眼”结构，为强降水的行成、维持提供了有利条件；而在无降水阶段，空中以孤立、分散的对流单体为主，但地面无明显降水；在连续降水阶段，雷达回波以弱积、层混合云为主，且中高空风向出现顺时针旋转，有利于降水的形成、发展，但整体降水强度较小。切变线过程不同阶段降水、雷达回波特征有着显著的区别，本文可以为高原切变线系统的预报提供理论参考。

Abstract: Based on the C-band new generation weather radar data, this paper focuses on a shear line precipitation process in Naqu, Xizang. Based on the characteristics of precipitation, this process was divided into three stages, and the radar echo characteristics and precipitation evolution process of each stage were analyzed. The results showed that during the instantaneous heavy precipitation stage, the radar echo in the Nagqu area mainly manifested as convective mixed clouds, and a more obvious “bull eye” structure appeared at the moment of maximum precipitation intensity, providing favorable conditions for the formation and maintenance of heavy precipitation; In the absence of precipitation stage, isolated and dispersed convective cells are mainly present in the air, but there is no significant precipitation on the ground; During the continuous precipitation stage, the radar echoes are mainly composed of weakly integrated and layered mixed clouds, and the wind direction in the middle and high altitudes rotates clockwise, which is conducive to the formation and development of precipitation, but the overall precipitation intensity is relatively small. There are significant differences in precipitation and radar echo characteristics at different stages of the shear line process, and this article can provide theoretical reference for the prediction of plateau shear line.