2014年南京市一次强雷暴天气过程分析

Analysis of a Severe Thunderstorm Weather in Nanjing in 2014

摘要: 本文利用常规气象观测资料、NCEP 1˚ × 1˚再分析资料、闪电资料以及多普勒雷达资料，对南京市2014年9月28日一次强雷暴天气过程进行分析。结果表明：(1) 雷暴发生前南京数日持续高温累积了大量不稳定能量是先决条件，冷空气南下触发不稳定能量的释放是触发机制。(2) 此次雷暴为湿雷，以负闪为主(占93%)。强对流天气集中在北部和中部，其中中西部为闪电密集区。(3) 强烈的上升运动以及高空辐散、低空辐合的配置为动力学机制；较强的水汽输送和高的相对湿度提供了良好的水汽条件；稳定性指数表明此次雷暴过程是强动力和强动热力不稳定条件共同作用的结果。(4) 强雷电区雷达特征表现为回波强度维持在45 dBz以上，风廓线表现为低层为偏东风，中低层为偏西风，回波顶高度维持在14 km左右，零速度线呈明显的“S”形。

Abstract: A strong thunderstorm weather process on September 28, 2014 in Nanjing is analyzed by using the conventional meteorological observation data and NCEP 1˚ × 1˚ reanalysis data, lightning data and Doppler radar data. The results showed that: (1) before the occurrence of the thunderstorm, the high temperature persisting in Nanjing region was found, which had cumulated mass instable energy that should be seen as the prerequisite, and the southward cold air stirred up this instable energy, which was the induced factor of this thunderstorm. (2) The process is wet thunderstorm, and negative flashes account 93 percent. Strong convection weather was concentrated in northern and central area of Nanjing, the Midwest is intensive lightning zone. (3) The upper divergence and low-level convergence and strong upward movement are the dynamic mechanism of the thunderstorm. Strong water vapor transport and high relative humidity provided good moisture conditions. The results of the analysis of the stability index show that the thunderstorm is the result of the common function of the strong dynamic instability and thermal instability. (4) Radar features in the strong lightning region show that the echo intensity is maintained above 45 dBz, the wind profile shows that the low level is the east wind, the middle and low level is the west wind, the echo top height is maintained at about 14 km, and the zero velocity line shows an obvious “S” shape.