纬向切变线暴雨落区的精细化分析

Fine Analysis on the Rainfall Distribution of Zonal Shear Line Heavy Rain

应用常规观测资料、NCEP 1°×1°再分析资料,对纬向切变线的暴雨落区进行精细化分析。结果表明:虽然低层切变线的位置对暴雨落区很重要,但不是判断暴雨落区的唯一依据。影响系统的空间结构及冷暖空气的相互作用对暴雨落区的精细化预报至关重要。当东北地区有冷空气入侵,山东省为一致东北风时,除了与切变线对应的暴雨区,还有因锋面抬升作用造成的地面东北风中的暴雨区;而当东北地区为暖低压,850 hPa冷中心盘踞山东省时,切变线南侧西南暖湿气流强盛,此时暴雨区位于切变线南侧和地面静止锋之间的鲁南地区;风场辐合中心往往和高湿舌对应,高湿舌前部和风场辐合中心附近是暴雨落区。

Based on the conventional observational data and NCEP 1 ° X 1 ° reanalysis data, the rainfall distribution of zonal shear line heavy rain was refinedly analyzed. The results show that, although the location of lowlevel shear line is important to the distribution of heavy rain, it is not the unique decisive factor to the distribution. The spatial structure of affecting system and the interaction between cold and warm air are essential to the heavy rain fine forecast. With the cold air invasion from the northeast region of China and northeast wind crossing Shandong Province, there are two rainfall areas. One is related with the shear line, and the other is caused by frontal uplift of the ground northeast of the heavy rain area. When a warm low is located in the northeast region of China and 850 hPa cold center entrenched in Shandong Province and there is a strong southwest warm air flow with shear line, the rainfall area of heavy rain is located be tween the shear line and the stationary front in South Shandong Province. Wind convergence center is of ten accompanied with high humidity area, and the rainfall area is usually located in the front of high hu midity area and near wind convergence center.