| 北亚洲大陆冬季地表感热通量对我国江淮梅雨的影响 |
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| 引用本文： | 陈圣劼,李栋梁,何金海.北亚洲大陆冬季地表感热通量对我国江淮梅雨的影响[J].高原气象,2012,31(2):359-369. |
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| 作者姓名： | 陈圣劼 李栋梁 何金海 |
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| 作者单位： | 南京信息工程大学大气科学学院／气象灾害省部共建教育部重点实验室,江苏南京,210044 |
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| 基金项目： | 国家自然科学基金项目，公益性行业(气象)专项 |
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| 摘 要： | 利用1979—2008年NCEPⅡ月平均地表感热通量再分析资料、江苏省气象台整编的江淮出入梅日期和全国753个测站逐日降水资料,分析了亚洲北部(60°～135°E,32°～75°N,简称北亚洲)大陆冬季地表感热通量对我国江淮梅雨的影响及其可能机制。结果表明,北亚洲大陆地表在冬季总体为感热冷源,对大气起到强冷却作用。通过定义WSH指数来表征北亚洲大陆冬季地表感热冷源的强度,该指数值越小,冷源越强;反之,冷源越弱。当冬季北亚洲大陆地表感热冷源偏强时,夏季梅雨锋北侧的冷空气强度大范围加强,东北冷涡增强,且冷空气向南输送增强;7月高空副热带西风急流位置偏南,南亚高压呈青藏高压型;江淮流域上升运动增强,且该流域上空高层变干、低层变湿,大气层结的不稳定度增加,对流活动增强,有利于梅雨降水,出梅偏晚。冬季地表感热冷源偏弱时,情况则相反。因此,冬季北亚洲大陆地表感热通量的异常对汛期江淮梅雨的预测具有一定的指示意义。
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| 关 键 词： | 北亚洲大陆 冬季 地表感热通量 江淮梅雨 东北冷涡 |
Influence of the Surface Sensible Heat Flux of North Asian Continent in Winter on Meiyu in Yangtze-Huaihe Valleys |
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| CHEN Sheng-jie,LI Dong-liang,HE Jin-hai.Influence of the Surface Sensible Heat Flux of North Asian Continent in Winter on Meiyu in Yangtze-Huaihe Valleys[J].Plateau Meteorology,2012,31(2):359-369. |
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| Authors: | CHEN Sheng-jie LI Dong-liang HE Jin-hai |
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| Institution: | (Nanjing University of Information Science and Technology/Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing 210044,China) |
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| Abstract: | Based on the monthly mean values of surface sensible heat flux(SSHF) from NCEPⅡ reanalysis data,the onset and end date of Meiyu in Yangtze-Huaihe valleys provided by Jiangsu Meteorological Administration,and the observed daily precipitation at 753 stations from 1979 to 2008,the influence of the SSHF of the North Asian Continent(60°~135°E,32°~75°N) in Winter on Meiyu and its possible mechanism are analyzed.The results show that the surface of the North Asian Continent in winter is a cold source of sensible heat,which is strong cold air action to the atmosphere.Here,an index WSH is defined as a measurement of the intensity of this cold source,the lower(higher) index indicates the stronger(weaker) cold source.During the strong year of the cold source of the surface sensible heat,the cold air to the north of Meiyu front and the northeast cold vortex in summer is intensified widely,and the longitude circle is also strengthened.Meanwhile the subtropical westerly jet is anomalously southward and the South Asian high is far southeast-ward in July,resulting in the stronger ascending flow over Yangtze-Huaihe valleys,where the upper-level air turning to be drier while the low-level air turning to be wetter dramatically cause a more unstable air layer and severe convective activity.All above contributes to more precipitation and delays the end date of Meiyu.The reversal is true for the weaker years of the cold source of the sensible heat.In view of these,the anomaly of SSHF of the North Asian Continent in winter could act as an indicative signal in predicting Meiyu in Yangtze-Huaihe valleys during flood season. |
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| Keywords: | North Asian continent Winter Surface sensible heat flux Meiyu in Yangtze-Huaihe |
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