| 摘要: |
| 利用日常业务常规高空和地面探测、观测资料，地面加密自动站分钟数据资料以及榕江站、贵阳站C波段多普勒天气雷达探测资料，分析了2020年3月23日贵州榕江飑线大风及长顺大冰雹的成因及雷达回波特征 。结果表明：（1）此次飑线大风与大冰雹发生在南支槽前暖区，地面热低压发展推动辐合线移动、低层西南暖湿气流、中层干冷空气、合适的0℃和-20℃高度均为此次飑线大风及大冰雹的产生提供了有利的环境条件。（2）雷达回波大冰雹特征突出：强回波悬垂，有界弱回波区，弓形回波，中心强度强（60dBz以上）且50dBz强回波伸展超过-20℃高度达到9km以上，垂直积分液态水含量最高达到了70kg/m2，连续超过两个体扫VIL≥60kg/m2，回波顶高连续超过两个体扫在15km以上。（3）飑线雷达回波大风特征明显：弓形回波形态特征明显且移动较快，移速约40千米/小时，低层径向速度大，中层径向辐合大风区下传，速度零线通过观测站后大风加速。（4）短临预警业务中，对飑线大风天气，应重点关注低仰角速度大值区、中层径向辐合和弓形带状回波生成后移动发展对下游地区的影响；对大冰雹天气，应重点关注大于50dBZ强回波垂直扩展的高度、VIL和ET高值区的维持等。 |
| 关键词: 大冰雹;飑线大风;雷达回波; |
| DOI： |
| 投稿时间：2020-07-16修订日期：2020-11-10 |
| 基金项目: |
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| Analysis on Structural Features of Warm-Sector Squall Line and Large Hail in Guzhou on 23 March 2020 |
| XU Ke,DU Xiaoling,ZHOU Wenyu,QI Dapeng,GU Tianhong |
| (Guizhou Meteorological Observatory) |
| Abstract: |
| Based on conventional observational data, ground encryption automatic station minute data and C-band doppler radar data in Guiyang and Rongjiang, this paper analyzes the reason and radar echo characteristics of severe hail and squall line occurs in Guizhou on 23 March 2020. The results show that: (1)This severe convection process happens in warm-sector before southern branch trough, benefits from the movement of ground convergence line caused by the development of ground thermal low, the low-level southwest warm and humid air, the middle-level cold and dry air, the appropriate 0℃ and -20℃ layer height. (2) The radar echo has the characteristics of large hail: Strong overhanging echo, boundary weak echo region, bow echo, strong radar echo center intensity (greater than 60 dBz) and the height of 50 dBz extends more than 9 kilometers which is above -20℃ layer height, the highest vertical integrated liquid (VIL) is 70 kg·m-2, both VIL greater than 60 kg·m-2 and echo top(ET) greater than 15km are lasted more than two volume scans. (3) The radar echo also has the characteristics of squall line: Bow echo with quick speed (about 40 km·h-1), high radial velocity in the lower layers, mid altitude radial convergence and downward gale area, the wind speed of the observation station speeds up after zero speed line passes by. (4) For squall line nowcasting and warning, more attention should be paid to the high value area of low elevation radial velocity, the effect of the motion and development of mid altitude radial convergence and bow echo to the downstream region. For large hail nowcasting and warning, the vertical stretching height of strong radar echo (greater than 50 dBz), the maintenance time of the large area of VIL and ET should be focused on. |
| Key words: large hail; squall line; radar echo; |
