摘要
通过跟踪一次中尺度带状对流系统（MCS）初生、发展、减弱的演变全过程，对地闪资料和多普勒雷达资料进行“粗化”格点处理，定性和定量地分析了地闪活动特征与组合反射率（CR）、垂直累积液态含水量（VIL）和回波顶高（ET）等雷达资料之间的相互关系。结果 表明在MCS强雷暴演变过程中：①总地闪数的96．7％集中落在CR为45～55dBz的回波区域内，在CR大于60dBz的强回波区域内地闪总数却很少；地闪密集中心的位置与CR大于等于50dBz的强度中心常常重合；②地闪密集中心与VIL中心常常不重合，常落在VIL高值中心的边缘或落在VIL为20-30kg·m^-2的区域中；在VIL小于20kg·m^-2的地方存在较为活跃的地闪。在VIL大于40kg·m^-2等值线范围内出现的地闪总数较少，在VIL大于50kg·m^-2的强中心几乎没有地闪出现；③单位时间间隔6min内的地闪总数随回波顶高的变化并不明显，但与回波顶高于11km的面积范围有着很好的正相关，表明组成MCS的云塔达到较高高度的水平面积对地闪活动的激烈程度有关。
The relations between Cloud-to-Ground （CG） lighting activity and radar-echo products, including CR （Composite Reflectivity）, VIL （Vertical Integrated Liquid water）, ET （Echo Top）, are analyzed quantitatively and qualitatively through tracing the generation, developemnt and mitigation of a MCS （Mesoscale Convective System） thunderstorm process, after the ＂coarsening＂ grid processing of CG and Doppler data. The results show ： 96.7 % of CG appeared within the range of 40 to 55 dBz, and the center of maximum CG density always coincided with the center of intense echoes, but CGs seldom appeared above 65 dBz. often concentrated around the area with VIL greater than 40 kg＂ m-2, and the center of maximum CGdensity frequently located around the margin of the center of VIL. The number of CGs was correlated with the area of ET greater or equal to 11 km, which indicates that the area with cloud top up to a relatively high level in MCS influences greatly the intensity of CG lightning activity.
出处
《气象科技》
2007年第5期665-669,I0002,共6页
Meteorological Science and Technology
基金
中国气象局新技术推广项目预报员专项(CMATG2006Y06)资助
关键词
MCS
地闪特征
多普勒雷达资料
mesoscale convective system, cloud-to-ground lightning, radar data （CR/VIL/ET）
