叶成志,吴贤云,黄小玉. 2009. 湖南省历史罕见的一次低温雨雪冰冻灾害天气分析[J]. 气象学报, 67(3):489-500, doi:10.11676/qxxb2009.049
湖南省历史罕见的一次低温雨雪冰冻灾害天气分析
A synoptic analysis of the unprecedented severe event of theconsecutive cryogenic freezing rain in Hunan Province
投稿时间:2008-08-06  修订日期:2009-03-27
DOI:10.11676/qxxb2009.049
中文关键词:  低温雨雪冰冻灾害, 冰冻分布地域特征, 强冰冻成因
英文关键词:Cryogenic freezing rain and snow weather, Distribution characteristic, Causal analysis of the freezing event 
基金项目:国家科技部公益类行业专项(GYHY200706012)、湖南省局重点课题(200602)和湖南省科技计划重大专项(2008FJ1006)
作者单位
叶成志 中国气象局武汉暴雨研究所武汉430074
湖南省气象台长沙410007 
吴贤云 湖南省气候中心长沙410007 
黄小玉 湖南省气象台长沙410007 
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中文摘要:
      在欧亚大陆中高纬度稳定维持阻塞形势的环流背景下,2008年1月10日—2月2日中国南方地区连续经历了4次历史罕见的大范围低温雨雪冰冻天气过程。应用多种常规、非常规观测资料及NCEP再分析资料,在对该过程的大尺度环流及水汽输送特征进行诊断分析的基础上,细致分析了受灾最为严重的湖南省冰冻分布地域特征、多种气象因子及特殊地形对冰冻强度的影响,并对造成降水性质差异及强冰冻的成因进行了探讨。结果表明:中高纬阻塞高压、西太平洋副高及南支槽是造成此次持续性雨雪天气的主要影响系统,持续而强盛的水汽输送对雨雪冰冻的强度和范围起重要作用;冰冻形成与增长是多种气象因子综合影响的结果。地面日平均温度、700 hPa风向风速、逆温强度及冷垫厚度对冰冻强度预报有很好的指示意义。当冰冻形成条件具备后,融化层及冷垫越深厚、地面日平均气温越低则冰冻发展越显著。若700 hPa维持强盛的西南急流、850 hPa持续偏东北风时,最有助于逆温加强,冷垫增厚。强冰冻的预报着眼点应关注700 hPa附近的剧烈增温、增湿及850 hPa以下的强降温;近地面层丰富的过冷水滴和叠置于深厚冷气层之上的暖性“逆温层”的建立和维持是大范围强冰冻天气产生的一个重要原因;此外,湖南特殊的地理位置及复杂的地形地貌特征对冰冻的持续和发展有较大影响。
英文摘要:
      Four consecutive large-scale disastrous weather processes of the cryogenic freezing rain and snow storm occurred in southern China from 10 January to 2 Feburary, 2008,due to the Ural blocking high residing stably over the Eurasian mid-high latitudes. In this paper, based on the multiple conventional and non-conventional observational data as well as the NCEP reanalysis data, the freezing rain distribution and evolution characteristics over the worst stricken areas of Hunan Province are analyzed in detail via diagnosing the anomalous atmosphere circulation and water vapor transport as well as some related synoptic factors. Moreover, the topographic effect on this event is discussed, and the causes of various precipitation formation, including the development mechanism responsible for the strong freezing rain, are investigated. The results show that the Ural blocking high, the western Pacific subtropical high and the deep trough over Indian and Burma are the key weather systems which led to the occurrence of the whole event. In the meantime, the abundant and continuous supplementation of water vapor is very favorable to enhancing the intensity and scale of the freezing rain. In addition, the plentiful super cooled water drops near the ground and the warm-type inversion layer imposed below the deep cold layer are possibly the key factors to maintaining such unprecedented weather processes. The formation and devoplement of the freezing rain can be attributed to the combined effects of a variety of meteorological factors. On the other hand, the daily average surface temperature, 700 hPa wind field, inversion temperature intensity and thickness of the cooling layer are useful to predict the freezing intensity. The thicker the melting layer and the deeper the underlying cooling layer with a lower averaged daily surface temperature, the more remarkable the development of the freezing rain was. The key points for the freezing prediction should be whether there are intense increases of temperature and humidity around 700 hPa as well as a strong temperature reduction below 850 hPa. The strong southwesterly jet at 700 hPa and the sustained northeasterly at 850 hPa greatly contributed to the inverse temperature reinforcement and the thickness growth of the cooling layer. Furthermore, the special topography and the complex terrain over Hunan Province also exerted great impacts on the occurrence and development of the freezing event.
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