Impact of the Intraseasonal Variability of the Western North Pacific Large-Scale Circulation on Tropical Cyclone Tracks

NCU Institutional Repository > 地球科學學院 > 大氣物理研究所 > 期刊論文 > Item 987654321/27333

jsp.display-item.identifier=請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/27333

题名:	Impact of the Intraseasonal Variability of the Western North Pacific Large-Scale Circulation on Tropical Cyclone Tracks
作者:	Chen,TC;Wang,SY;Yen,MC;Clark,AJ
贡献者:	大氣物理研究所
关键词:	SOUTH CHINA SEA;MONSOON;SUMMER;OSCILLATION;REANALYSIS;ANOMALIES;MOTION;FLOW
日期:	2009
上传时间:	2010-06-29 18:36:23 (UTC+8)
出版者:	中央大學
摘要:	The life cycle of the Southeast Asian-western North Pacific monsoon circulation is established by the northward migrations of the monsoon trough and the western Pacific subtropical anticyclone, and is reflected by the intraseasonal variations of monsoon westerlies and trade easterlies in the form of an east-west seesaw oscillation. In this paper, an effort is made to disclose the influence of this monsoon circulation on tropical cyclone tracks during its different phases using composite charts of large-scale circulation for certain types of tracks. A majority of straight-moving (recurving) tropical cyclones appear during weak (strong) monsoon westerlies and strong (weak) trade easterlies. The monsoon conditions associated with straight-moving tropical cyclones are linked to the intensified subtropical anticyclone, while that associated with recurving tropical cyclones is coupled with the deepened monsoon trough. The relationship between genesis locations and track characteristics is evolved from the intraseasonal variation of the monsoon circulation reflected by the east west oscillation of monsoon westerlies and trade easterlies. Composite circulation differences between the flows associated with the two types of tropical cyclone tracks show a vertically uniform short wave train along the North Pacific rim, as portrayed by the Pacific-Japan oscillation. During the extreme phases of the monsoon life cycle, the anomalous circulation pattern east of Taiwan resembles this anomalous short wave train. A vorticity budget analysis of the strong monsoon condition reveals a vorticity tendency dipole with a positive zone to the north and a negative zone to the south of the deepened monsoon trough. This meridional juxtaposition of vorticity tendency propagates the monsoon trough northward. The interaction of a tropical cyclone with the monsoon trough intensifies the north-south juxtaposition of the vorticity tendency and deflects the tropical cyclone northward. In contrast, during weak monsoon conditions, the interaction between a tropical cyclone and the subtropical high results in a northwestward motion steered by the intensified trade easterlies. The accurate prediction of the monsoon trough and the subtropical anticyclone variations coupled with the monsoon life cycle may help to improve the forecasting of tropical cyclone tracks.
關聯:	WEATHER AND FORECASTING
显示于类别:	[大氣物理研究所 ] 期刊論文

文件中的档案:

档案	描述	大小	格式	浏览次数
index.html		0Kb	HTML	568	检视/开启

在NCUIR中所有的数据项都受到原著作权保护.

社群 sharing

数据加载中.....