澳大利亚冷空气活动对西太平洋热带气旋生成的影响
投稿时间: 2015-03-04  最后修改时间: 2015-03-04  点此下载全文
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作者单位E-mail
陈笑晨 南京信息工程大学 zhi@nuist.edu.cn 
智协飞 南京信息工程大学 zhi@nuist.edu.cn 
赵欢 南京信息工程大学  
陈龙 南京信息工程大学  
基金项目:国家重大科学研究计划项目(2012CB955200);江苏高校优势学科建设工程资助项目(PAPD); 江苏省 “青蓝工程” (东亚季风与区域气候变化)
中文摘要:利用1980-2012年NCEP/NCAR 再分析资料以及中国气象局的最佳台风路径资料,确定了澳大利亚冷空气活动影响低纬地区的关键区,并定义了一个澳大利亚冷空气活动强度指数。利用合成分析和相关分析方法研究了北半球夏季澳大利亚冷空气活动对西北太平洋热带气旋生成的影响。结果表明,澳大利亚冷空气侵入低纬的关键区为澳大利亚东北部的珊瑚海地区,该区经向风风速与越赤道气流及赤道西风都有很好的相关关系。关键区经向风风速还与同期的SOI指数也有很好的相关关系,当SOI指数偏低(高)时关键区经向风风速偏强(弱)。澳大利亚冷空气活动强、弱年西太平洋热带气旋生成的位置与季风槽的变化一致。强年季风槽偏强偏东,热带气旋生成位置偏东偏南,而弱年季风槽偏弱偏西,热带气旋生成位置偏西偏北。低层涡度场,水汽输送,风垂直切变以及低纬度地区对流活动的分布都表明,强年有利于热带气旋生成位置偏东偏南,弱年偏西偏北。
中文关键词:澳大利亚冷空气活动  强度指数;西太平洋热带气旋  SOI
 
Influence of the cold air activity over Australia on the tropical cyclone genesis in western Pacific
Abstract:Based on the NCEP/NCAR reanalyses and the best track data of the typhoons provided by China Meteorological Administration, the key area of the influence of the cold air activity over Australia on the low latitudes was determined, and a cold air intensity index over Australia was defined. The influence of the cold air activity over Australia on the tropical cyclone genesis over western Pacific was investigated by using composite and correlation coefficient analyses. The results show that the Coral Sea is the key area of the influence of the cold air over Australia on low latitudes. The meridional wind over the Coral Sea is closely related to the cross-equatorial flows and westerlies over the Equator as well as the SOI. As SOI is weaker (stronger), the meridional wind over the Coral Sea (CSV) is stronger (weaker). The location of the tropical cyclone genesis over western Pacific coincides with the variation of the monsoon trough during the years of strong and weak cold air activities over Australia. The monsoon trough over western Pacific is stronger and located eastward than normal, the location of the tropical cyclone genesis is eastward and southward than normal during years of strong cold air activity, while the monsoon trough is weaker and located westward than normal, the location of the tropical cyclone genesis is westward and northward than normal during years of weak cold air activity. The distribution of vorticity in lower troposphere, the moisture transport, the vertical shear of horizontal wind and the convections in low latitudes indicates that the locations of the tropical cyclone over western Pacific are eastward and southward (westward and northward) than normal during strong (weak) years of cold air activities over Australia.
keywords:cold air activity over Australia  intensity index  tropical cyclone over western Pacific  SOI
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