| 影响广西的两次台风暴雨中尺度对比分析 |
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| 引用本文： | 赵金彪,韩慎友,李佳颖.影响广西的两次台风暴雨中尺度对比分析[J].湖北气象,2014(2):156-162. |
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| 作者姓名： | 赵金彪 韩慎友 李佳颖 |
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| 作者单位： | 广西壮族自治区气象台,南宁530022 |
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| 基金项目： | 广西科学研究与技术开发计划项目（桂科攻10123009-8）;广西自然科学基金项目（2011GXNSFN018011） |
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| 摘 要： | 利用多普勒天气雷达、地面加密观测资料及NCEP格点再分析资料,从低层环境场、雷达回波特征、湿位涡分布等方面,对比分析路径相似的"启德"(1213号)和"纳沙"(1117号)台风造成广西降水条件的差异。结果表明:"启德"东侧的东南风急流强,水汽强辐合中心偏于台风中心附近,降水强度大,而"纳沙"水汽辐合主要位于东北气流与东南气流的汇合区,降水范围大;两者在越南北部登陆后其后部均存在窄长带状的中尺度强回波特征,但"纳沙"的螺旋回波雨带伸展范围更宽、持续时间更长;"纳沙"因有冷空气侵入,近地面层气流出现多个分支,更有利于形成中尺度涡旋和气流汇合带,是其比"启德"产生较大范围强降水的重要因素;两者的降水分布与低层湿位涡负值区有较好对应关系,强降水落区主要位于湿正压项(VMPV1)负值区和斜压项(VMPV2)正值区相叠加的区域,而"启德"的VMPV1负值比"纳沙"小,其对应的降水强度也较大。
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| 关 键 词： | 台风暴雨 水汽辐合 中尺度滤波 湿位涡 |
Comparative analysis of two heavy rain events affecting Guangxi associated with typhoon Kai-tak and Nesat |
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| ZHAO Jinbiao,HAN Shenyou,LI Jiaying.Comparative analysis of two heavy rain events affecting Guangxi associated with typhoon Kai-tak and Nesat[J].Meteorology Journal of Hubei,2014(2):156-162. |
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| Authors: | ZHAO Jinbiao HAN Shenyou LI Jiaying |
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| Institution: | (Guangxi Meteorological Observatory, Nanning 530022) |
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| Abstract: | Using data from Doppler weather radar, intensive automatic weather stations and NCEP reanalysis , we have analyzed the differ-ences of environmental conditions in producing rainfalls in Guangxi by typhoon Kai-tak （1213） and Nesat （1117）, which had similar tracks, focusing on their low-level environment fields, radar reflectivity and contribution of moist potential vorticity （MPV） etc. Results show that there is a strong southeasterly jet on the east side of Kai-tak, and a strong moist convergence center tends to be around the typhoon center where there is the intense rainfall, while the moisture convergence zone formed by typhoon Nesat mainly locates in the area where northeaster-ly was met by southeasterly, and rain fell in a broader area. There is a narrow and long strong mesoscale radar echo band in the back of ty-phoon Kai-tak and Nesat after they made landfall the northern Viet Nam. Although the spiral rain band around Nesat stretched over a wider range and lasted for a longer period. There were the multiple airflow branches near the ground around Nesat because of the intrusion of cold air that is more favorable to the formation of mesoscale vortex and airflow convergence zone, which is believed to be the main reason that leads to a broader area of severe precipitation in Nesat than in Kai-tak. The rain area induced by two typhoons well corresponds to the negative val-ue centers of MPV. Their severe precipitation centers are situated where negative moist barotropc term VMPV1 is overlapped by positive baro-clinic term VMPV2. Since the negative VMPV1 value in the rain zone generated by Kai-tak is smaller than that by Nesat, the rainfall caused by Kai-tak is stronger than that by Nesat. |
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| Keywords: | heavy rain caused by typhoon water vapor convergence mesoscale filter moist potential vorticity |
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