大气科学学报
大氣科學學報
대기과학학보
JOURNAL OF NANJING INSTITUTE OF METEOROLOGY
2012年
2期
163-174
,共12页
何洁琳%管兆勇%万齐林%王黎娟
何潔琳%管兆勇%萬齊林%王黎娟
하길림%관조용%만제림%왕려연
热带气旋%东风波%赤道混合Rossby重力波%大尺度环流%冬季
熱帶氣鏇%東風波%赤道混閤Rossby重力波%大呎度環流%鼕季
열대기선%동풍파%적도혼합Rossby중력파%대척도배류%동계
tropical cyclone%easterly wave%equatorial mixed Rossby gravity wave%large-scale circulation%wintertime
利用合成技术对1995—2006年冬季(11月—次年2月)生成在西北太平洋上的34个热带气旋(tropicalcyclone,TC)个例进行分析,研究冬季西北太平洋TC生成的大尺度环流特征及其生成机制,结果表明:冬季TC生成的大尺度环流特征型为东风波西传型;北半球冬季对流层低层出现的跨赤道气旋对是冬季北半球TC形成的重要特征;太平洋中部赤道混合Rossby重力波西北传,与强对流中心重合,性质转为"热带低压型扰动",为冬季热带气旋生成提供扰动源。对合成TC初始场的涡动扰动动能的收支分析表明,涡动有效位能和正压不稳定转换为TC形成提供了能量,这两种能量分别与积云对流加热和水平不均匀气流有关。正压不稳定能量转换为动能主要位于对流层中下层,而扰动有效位能的转换主要位于对流层中上层。低层热带东风波动从平均气流中获得正压不稳定能量,并与强积云对流耦合,热力和动力共同作用下形成TC。
利用閤成技術對1995—2006年鼕季(11月—次年2月)生成在西北太平洋上的34箇熱帶氣鏇(tropicalcyclone,TC)箇例進行分析,研究鼕季西北太平洋TC生成的大呎度環流特徵及其生成機製,結果錶明:鼕季TC生成的大呎度環流特徵型為東風波西傳型;北半毬鼕季對流層低層齣現的跨赤道氣鏇對是鼕季北半毬TC形成的重要特徵;太平洋中部赤道混閤Rossby重力波西北傳,與彊對流中心重閤,性質轉為"熱帶低壓型擾動",為鼕季熱帶氣鏇生成提供擾動源。對閤成TC初始場的渦動擾動動能的收支分析錶明,渦動有效位能和正壓不穩定轉換為TC形成提供瞭能量,這兩種能量分彆與積雲對流加熱和水平不均勻氣流有關。正壓不穩定能量轉換為動能主要位于對流層中下層,而擾動有效位能的轉換主要位于對流層中上層。低層熱帶東風波動從平均氣流中穫得正壓不穩定能量,併與彊積雲對流耦閤,熱力和動力共同作用下形成TC。
이용합성기술대1995—2006년동계(11월—차년2월)생성재서북태평양상적34개열대기선(tropicalcyclone,TC)개례진행분석,연구동계서북태평양TC생성적대척도배류특정급기생성궤제,결과표명:동계TC생성적대척도배류특정형위동풍파서전형;북반구동계대류층저층출현적과적도기선대시동계북반구TC형성적중요특정;태평양중부적도혼합Rossby중력파서북전,여강대류중심중합,성질전위"열대저압형우동",위동계열대기선생성제공우동원。대합성TC초시장적와동우동동능적수지분석표명,와동유효위능화정압불은정전환위TC형성제공료능량,저량충능량분별여적운대류가열화수평불균균기류유관。정압불은정능량전환위동능주요위우대류층중하층,이우동유효위능적전환주요위우대류층중상층。저층열대동풍파동종평균기류중획득정압불은정능량,병여강적운대류우합,열력화동력공동작용하형성TC。
Thirty four cases of topical cyclogenesis that occurred in boreal winter(November to February of next year) during 12-yr(1995—2006) have been analyzed by using the composite technique for further understanding of the larger-scale circulation features and the mechanism of the formation of tropical cyclone in the western north Pacific(WNP)during wintertime.It has been found that the easterly waves play a major role in the tropical cyclogenesis.The existence of low-level cross-equatorial tropical cyclone pairs is a remarkable feature in the formation of tropical cyclogenesis.The equatorial mixed Rossby-gravity(MRG) waves in lower troposphere propagated northwestward from the central Pacific.These waves developed into the TD-type disturbances in place where the strong convection overlaps,which provided disturbances for the tropical cyclogenesis.Further analysis in terms of eddy kinetic energy budgets for the TC(tropical cyclone) related with circulations indicates that the available potential energy of disturbances and the energy that converts barotropically from the mean kinetic energy facilitates the TC formation.These two kinds of energy are associated with cumulus convection heating and the asymmetric horizontal flow respectively.The barotropic energy conversion mainly occurs in the low and mid-troposphere while the available energy conversion locates in the mid and upper troposphere.The tropic easterly waves get barotropic instability energy from the mean flow and coupled with the deep convection,inducing the formation of TCs under the interaction of dynamics and thermodynamics.