台风“莫拉克”登陆过程的闪电活动与雷达回波特征

Characteristics of Lightning Activity and Radar Reflectivity during Typhoon ‘Morakot’ Landfall

利用全球闪电定位网WWLLN(World Wide Lightning Location Network)资料和中国气象局热带气旋资料中心最佳路径数据集的台风资料,并结合福建省气象局新一代天气雷达反射率资料以及NCEP/NCAR的再分析格点资料,对台风"莫拉克"在中国台湾和福建两次登陆过程中的闪电活动和雷达回波特征进行了分析。结果表明,闪电多发生在台风的外雨带,中心区域和内雨带闪电数量较少,第一次登陆过程中闪电数量较多,第二次登陆过程中闪电数量较少。6 km高度上,面积较大的回波后侧或外侧观测到闪电发生,在回波形成初期闪电数量较少,在面积和强度较稳定的时期闪电数量增加,并且闪电数量与回波的最大顶高呈正相关。闪电的发生受到台风自身垂直运动和地形抬升的共同影响,500 h Pa上气旋性风场流入垂直上升区后部的陆地出现闪电密集区,并且垂直中心的位置与强度对闪电分布的位置与数量有明显影响。

Using the lightning data from World Wide Lightning Location Network( WWLLN),typhoon track and intensity data from the Best Track Data Sets( CMA),radar reflectivity of the weather radar from Fujian Meteorological Administration and the NCEP/NCAR Global Reanalysis Data,to analyze the characteristics of lightning activity and radar reflectivity in typhoon ‘M orakot'( 0908) during the two processes of landfall in Taiwan and Fujian. The analysis showed that more lightning occurred in the outer rainband and less lightning occurred in the central area and inner rainband. The first landfall in Taiwan caused more lightning than the second landfall in Fujian. At 6 km height,lightning was prone to occur in the rear or round of the central area where the reflectivity value was high and the area was large. The lightning number was lowat the beginning of echo formation,and increased when the convective systems developed stably. During the period of typhoon entered into Taiwan Strait and made landfall in Fujian,the maximum echo height and lightning number had a positive correlation. The lightning activity was affected by both the vertical movement and topography. Lightning concentrated on the land at the rear side area of cyclonic horizontal wind flowed into the vertical upflowcentral areas on 500 h Pa. The position and intensity of the vertical upflowcentral areas influenced the position and number of lightning activity.