| 摘要: |
| 2020年6月12日凌晨，贵州遵义出现一次局地特大暴雨过程。局地强降水出现在正安碧峰镇，24 h过程雨量266.4 mm，2 h累计雨量达225.8 mm，最大小时雨强达163.3 mm·h-1 ，其中03时10—40分30 min雨量达到115.3 mm。利用常规高空和地面观测资料、地面加密观测资料、NCEP再分析资料、新一代C波段双偏振多普勒天气雷达资料等，结合特殊地形因素，初探碧峰极端短时强降水的形成原因。结果表明：①此次过程是在西太平洋副热带高压西进北抬，同时巴尔喀什湖—贝加尔湖横槽东移南下，西北地区—四川盆地低槽活跃的背景下产生的，强降雨主要出现在低层低涡切变附近及切变右前侧南风辐合区内，属暖区性质暴雨，偏南气流明显风速辐合和地面辐合线是正安碧峰特大暴雨的重要影响因子，深厚暖云层高效率降水增加了降水的极端性。②正安附近低层水汽辐合明显，高层处于南亚高压中心控制的强辐散区，高层辐散抽吸对强降水维持和加强有利；③雷达回波显示，回波呈后向传播，“列车效应”特征明显，且回波强度强、顶高高，垂直累积液态水含量极高,各种参数均能说明强降水时段水汽充沛、对流旺盛。双偏振雷达参数表明，可能存在大雨滴或一些融化的小冰粒，差分反射率和差分传播相移率同时较大，表明大雨滴数量多，大量大雨滴易产生强降水，暖云层厚，“低质心”高效率降水，因此总体降雨强度很强。④碧峰处在“喇叭口”地形内，东南气流进入“喇叭口”使降水更大、雨强更强。 |
| 关键词: 极端短时强降水；暖云降水；C波段双偏振雷达；地形增幅 |
| DOI： |
| 投稿时间：2021-05-26 |
| 基金项目:遵义市气象局科研项目（zyqxky[2018]09号）：遵义市短时强降水预报预警指标建立及适宜性分析 |
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| Application of Dual Polarization Radar in Extreme Short-time Heavy Rainfall in Zhengan Bifeng |
| XIAO Lei,GUO Xiaochao,LIU Hongshuang,WU Xinxing,HE mingyuan |
| (Zunyi Meteorological Bureau of Guizhou Province, Zunyi 563000 , China;Bozhou Meteorological Bureau of Guizhou Province, Zunyi 563100 , China;Wuchuan Meteorological Bureau of Guizhou Province, Wuchuan 564300 , China;Zhengan Meteorological Bureau of Guizhou Province, Zhengan 563400 , China) |
| Abstract: |
| In the early morning of June 12, 2020, a local severe rainstorm occurred in Zunyi, Guizhou. Local heavy rainfall occurs in Bifeng Town, Zhengan. The 24-hour process rainfall is 266.4 mm, the 2 hours cumulative rainfall is 225.8 mm, and the maximum hourly rainfall intensity is 163.3 mm·h-1, of which the rainfall in 30 minutes is 115.3 mm between 3∶10-3∶40. Using conventional high-altitude and ground observation data, ground encrypted observation data, NCEP reanalysis data, new generation C-band dual polarization Doppler weather radar data, combined with special topographic factors, this paper probes into the causes of extreme short-time heavy precipitation in Bifeng. The results show that: ① this process is produced under the back ground of the West Pacific subtropical high moving westward and northward, the Balkash Lake Baikal transverse trough moving eastward and southward, and the Northwest Sichuan Basin low trough active. The heavy rainfall mainly occurs near the low-level vortex shear and in the south wind convergence area at the right front of the shear, which is a warm region rainstorm. The obvious southerly air flow, wind speed convergence and ground convergence line are important factors affecting the severe rainstorm in Bifeng, Zhengan. Deep warm clouds and high-efficiency precipitation increase the extremes of precipitation. ② The water vapor convergence in the lower layer is obvious near Zhengan, and the upper layer is in the strong divergence area controlled by the South Asian high center. The high-level divergence suction is beneficial to the maintenance and strengthening of heavy precipitation; ③ The radar echo shows that the echo propagates backward, "train effect" is obvious, and the echo intensity is strong, the echo top is high, and the vertically accumulated liquid water content is very high. Various parameters can explain that there is plenty of water vapor and strong convection during heavy precipitation. The dual polarization radar parameters show that there may be heavy rain drops or some melted small ice particles, and the differential reflectivity and differential propagation phase shift rate are large at the same time, indicating that there are many heavy rain drops, a large number of heavy rain drops are easy to produce heavy precipitation, the warm cloud layer is thick, and the "low centroid" high-efficiency precipitation, so the total rainfall intensity is very strong. ④ Bifeng is located in the "bell mouth" terrain, and the southeast air flow enters the "bell mouth" to make the precipitation greater and the rain intensity stronger. |
| Key words: extreme short-time heavy precipitation； warm cloud precipitation； C-band dual polarization radar； terrain increase |
