热带大气准双周振荡对西北太平洋地区热带气旋路径的影响
投稿时间:2011-05-12  修订日期:2011-08-31  点此下载全文
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作者单位
陶丽 南京信息工程大学 气象灾害省部共建教育部重点实验室, 江苏 南京 210044 
李双君 南京信息工程大学 气象灾害省部共建教育部重点实验室, 江苏 南京 210044 
濮梅娟 江苏省气象局, 江苏 南京 210008 
夏瑛 江苏省气象局, 江苏 南京 210008 
基金项目:公益性行业科研专项(GYHY200806009);国家自然科学基金资助项目(40875038);江苏高校优势学科建设工程资助项目(PAPD)
中文摘要:利用美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,简称NOAA)的逐日对外长波辐射(outgoing longwave radiation,简称OLR)场资料,欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasting,简称ECMWF)逐日风场(850 hPa)资料,以及美国联合台风预警中心(Joint Typhoon Warning Center,简称JTWC)的热带气旋(tropical cyclone,简称TC)数据,参考Wheeler and Hendon(2004)提出的季节内振荡(Madden-Julian oscillation,简称MJO)指数,通过多元EOF方法定义热带准双周振荡(quasi-biweekly oscillation,简称QBW)指数,诊断分析了西北太平洋地区QBW不同位相对于TC路径的影响。结果表明,TC主要生成在QBW对流湿位相中,集中位置随QBW向西北的传播而向西北移动。在QBW位相phase1中,南海上空盛行QBW反气旋性环流,西太副高西伸,其西南侧偏东南气流受QBW反气旋性环流东北侧气流抑制,生成在副高南侧的TC首先在副高南侧偏东气流的引导下移动至近海,在西南季风以及副高西侧偏南气流作用下顺时针北折,因此在140°E以西转折类路径的TC比例最高;而在phase3中,西太副高偏东,南海上空盛行QBW气旋性环流,西太副高西南侧气流强度受QBW气旋东北侧气流影响增强,季风槽偏东,140°E以东转折类的TC比例最高。本文还对TC个例中的QBW流场形势进行了分析,发现当QBW气旋或反气旋环流中心同TC中心一致时,热带气旋路径会发生突然的右折。
中文关键词:准双周振荡  热带气旋  路径转折
 
Impact of QBW on TC's track change over the western North Pacific
Abstract:By using outgoing longwave radiation(OLR) data from National Oceanic and Atmospheric Administration(NOAA),daily wind (850 hPa) data from European Center for Medium-Range Weather Forecasting(ECMWF) and tropical cyclones(TC) data from Joint Typhoon Warning Center(JTWC),the impact of quasi-biweekly oscillation(QBW) on tropical cyclone activity over the western North Pacific(WNP) is studied in this paper.The index of 10 to 20-day oscillation is defined by referring to the Madden-Julian oscillation(MJO) index proposed by Wheeler and Hendon(2004).The analysis shows that TCs always occur in the area where convection is active.During QBW-phase1,the southeasterly of the western North Pacific subtropical high is weakened by the anticyclone-circulation of QBW.The westward (northwestward) moving TCs tend to change their tracks to the west of 140°E.During QBW-phase3,with the southeasterly of the western North Pacific subtropical high strengthened by the cyclone-circulation of QBW,TCs tend to change their tracks to the east of 140°E.Case studies of some TCs are discussed in this paper.The results show that TCs may present sudden poleward track change while its center overlaps with the center of the cyclone-circulations (anticyclone-circulations) of QBW.
keywords:quasi-biweekly oscillation  tropical cyclone  track change
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