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多源观测资料在六盘山西侧一次强对流暴雨中的应用OA北大核心CSTPCD

Application of Muti-Source Observation Data in a Severe Convective Rainstorm on the West Side of Liupan Mountains

中文摘要英文摘要

利用常规气象探测、ERA5逐1 h再分析、区域气象站、X波段双偏振、C波段多普勒及风廓线雷达等多源资料,对2022年7月15日六盘山西侧发生的一次被业务常用数值模式和预报员主观预报均漏报了的强对流暴雨进行综合分析.结果表明:此次暴雨发生在西太平洋副热带高压西北侧,主要落区为低层暖式切变线南侧及低空急流左前侧.在六盘山地形作用下,中尺度地面辐合线、中尺度西南急流和中尺度涡旋可能是此次暴雨的重要触发、维持和增强系统.暴雨由两条中尺度回波带造成,其上对流单体呈后向传播,存在明显的列车效应.地面5 min降水量明显增强前1~2 h,有低空急流加强、垂直风切变增加、急流中风速向下脉动和干侵入等现象,对暴雨预报预警有很好的参考意义.50 dBz以上强度回波面积、垂直积分液态水含量、回波顶高、大范围的差分传播相移(KDP)和差分反射率因子(ZDR)的大值区对强降水落区有较好的指示意义,KDP能较好反映强降水强度.最大KDP和ZDR均较最强5 min降水提前10 min出现,ZDR弧和ZDR柱也较最强5 min降水提前10~20 min出现.最强降水时段,KDP达3.0~4.0 °·km-1,对应ZDR为3.0~3.3 dB,相关系数为0.90~0.95,说明雨滴直径大且数浓度大,增加了降水的极端性.

The severe convective rainstorm that occurred on the west side of Liupan Mountains on 15 July 2022,which is missed by both the numerical weather prediction models and the subjective forecast of fore-casters,is analyzed based on the data from regional weather stations,X-band dual-polarization weather radar,C-band Doppler weather radar,wind profiler radar,and the ERA5 hourly reanalysis and conventional ob-servation data.The results show that the rainstorm occurred in the northwest side of the western Pacific subtropical high.The main area of severe rainfall was the south side of the low-level shear line and the left-front side of the low-level jet.Affected by the terrain of Liupan Mountains,the mesoscale ground conver-gence line,mesoscale low-level southwest jet and mesoscale vortex might be important systems of trigge-ring,maintaining and enhancing of the process.The rainstorm was caused by two mesoscale echo bands,on which the convective cells propagated backward,forming obvious train effect.The strengthening low-level jet,the increasing vertical wind shear,the downward disturbance of wind speed in the jet,and the dry intrusion appeared 1-2 h ahead of the increase in 5 min precipitation,which has a certain reference value for rainstorm forecast and early warning.The center of severe rainfall has a better corresponding re-lationship with the echo area with intensity ≥50 dBz and the large value area of vertical integrated liquid water,the echo tops,the large ranges of differential phase shift(KDP)and differential reflectivity(ZDR).KDP is a good indicator for intensity of severe rainfall.The maximum values of KDP and ZDR appeared 10 min earlier than the maximum rainfall in five minutes.The ZDR arc and ZDR column also appear 10-20 min earlier than the maximum rainfall.During the heaviest rainfall period,the KDP was 3.0-4.0 °·km-1,the ZDR was 3.0-3.3 dB,and the correlation coefficient was 0.90-0.95,which suggests that the spectrum of rain particulates contained a large amount of relatively large-sized raindrops,increasing the ex-tremity of precipitation.

张晓茹;苏洋;丁永红;薛宏宇;贾乐;孙艳桥

中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室,银川 750002||宁夏气象防灾减灾重点实验室,银川 750002||宁夏气象台,银川 750002中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室,银川 750002||宁夏气象防灾减灾重点实验室,银川 750002

大气科学

对流性暴雨低空急流中尺度地面辐合线X波段双偏振雷达风廓线雷达

convective rainstormlow-level jetmesoscale ground convergence lineX-band dual-polariza-tion weather radarwind profiler radar

《气象》 2024 (008)

929-940 / 12

宁夏回族自治区第五批青年科技人才托举工程项目(NXKJTJGC2021089)、中国气象局2023年复盘总结专项(FPZJ2023-147)、宁夏回族自治区重点研发计划项目(2022BBF02014)和宁夏自然科学基金项目(2022AAC03670、2023A0897)共同资助

10.7519/j.issn.1000-0526.2023.071002

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