| 移出型西南涡与我国中东部降水的关系 |
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| 引用本文： | 吴瑞姣,罗艳,余金龙.移出型西南涡与我国中东部降水的关系[J].气象科学,2019,39(6):818-826. |
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| 作者姓名： | 吴瑞姣 罗艳 余金龙 |
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| 作者单位： | 安徽省气象台, 合肥 230031,安徽省公共气象服务中心, 合肥 230031,安徽省气象科学研究所, 合肥 230031 |
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| 基金项目： | 安徽省气象局预报员专项资助项目（kY201611）；中国气象局预报员专项资助项目（CMAYBY2018-033） |
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| 摘 要： | 利用常规观测资料、逐日降水和NCEP再分析资料等统计2007—2017年5—7月西南涡共计199例,其中110例移出源地发展。在移出型西南涡中有66例沿偏东路径移动,占比60%;东北路径西南涡约占28.2%;东南路径西南涡仅占10.9%。移出型西南涡与我国中东部降水具有密切关系:偏东型有利于沿江地区降水增多;东北型使江北大部分地区降水增加;东南型有利于华南地区降水增加。偏东型和东北型西南涡中心路径与雨带走向近乎平行,但存在不同程度的偏移,造成偏移差异的直接原因在于低涡北侧是否有降水。研究表明:当高空无干冷侵入时,低涡南侧偏南风越强,北侧空气湿度越大,北侧低空有偏东气流将有利于北侧空气抬升产生降水;当高空存在干冷侵入时,若北侧低层有一支湿润的偏东气流,二者叠加形成对流不稳定,也有利于降水。
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| 关 键 词： | 移出型西南涡 雨带 差异分析 |
| 收稿时间： | 2018/7/4 0:00:00 |
| 修稿时间： | 2018/10/10 0:00:00 |
Statistical characteristics of moving-out southwest vortex and correlation between vortex and precipitation in central and eastern China |
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| WU Ruijiao,LUO Yan and YU Jinlong.Statistical characteristics of moving-out southwest vortex and correlation between vortex and precipitation in central and eastern China[J].Scientia Meteorologica Sinica,2019,39(6):818-826. |
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| Authors: | WU Ruijiao LUO Yan and YU Jinlong |
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| Institution: | Anhui Meteorological Observatory, Hefei 230031, China,Anhui Public Meteorological Service Center, Hefei 230031, China and Anhui Institute of Meteorological Sciences, Hefei 230031, China |
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| Abstract: | Based on several kinds of observed statistics and reanalysis data, the characteristics of moving-out southwest vortex from 2007 to 2017, and their effect to precipitation in central and eastern China were studied. There were 199 southwest vortices, of which 110 cases moved out of the origin in different paths. Among the 110 moving-out southeast vortices, 60% moved in eastward path, 28.2% in northeast path, and only 10.9% in southeast path. Precipitation in central and eastern China was closely related to moving-out southwest vortex. It was proved that the precipitation was heavier in regions along the Yangtze River during the life circle of eastward-vortex. During northeast-moving vortex''s life time, the precipitation increased in most area of north of Yangtze River. Coincidently, the precipitation in South China was heavier when vortex moving in southeast path. The routines of centers of vortices in eastward and northeast ways were nearly parallel to the axis of their rain bands, but not coincided. The direct cause of the deviation difference is whether there is precipitation on the north side of the vortex. Study showed, without dry and cold invasion at upper air, the stronger the southerly wind on the south side of the vortex was, the more humid the air on the north side. By this time, a low-level easterly air flow on the north side of vortex center may be conducive to the air uplift and local precipitation. When dry and cold invasion existed at upper air, a low-level easterly moist air flow may arouse convective instability, and this was also in favor of precipitation on the north side. |
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| Keywords: | southwest vortex rain band variance analysis |
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