DOI: 10.1007/s00382-012-1509-7
Scopus记录号: 2-s2.0-84879550108
论文题名: Signature of a southern hemisphere extratropical influence on the summer monsoon over India
作者: Viswambharan N. ; Mohanakumar K.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 41, 期: 2 起始页码: 367
结束页码: 379
语种: 英语
英文关键词: Indian summer monsoon
; Predictability
; Southern annular mode
; Southern extra tropics
英文摘要: The weakening relationship of El Nino with Indian summer monsoon reported in recent years is a major issue to be addressed. The altered relationships of Indian monsoon with various parameters excite to search for other dominant modes of variability that can influence the precipitation pattern. Since the Indian summer monsoon circulation originates in the oceanic region of the southern hemisphere, the present study investigates the association of southern extratropical influence on Indian summer monsoon using rainfall and reanalysis parameters. The effect of Southern Annular Mode (SAM) index during the month of June associated with the onset phase of Indian summer monsoon and that during July-August linked with the active phase of the monsoon were analysed separately for a period from 1951 to 2008. The extra-tropical influence over the monsoon is illustrated by using rainfall, specific humidity, vertical velocity, circulation and moisture transport. The June high SAM index enhances the lower level wind flow during the onset phase of monsoon over Indian sub-continent. The area of significant positive correlation between precipitation and SAM in June also shows enhancement in both ascending motion and specific humidity during the strong phase of June SAM. On the other hand, the June high SAM index adversely affects July-August monsoon over Indian subcontinent. The lower level wind flow weakens due to the high SAM. Enhancement of divergence and reduction in moisture transport results in the Indian monsoon region due to the activity of this high southern annular mode. The effect is more pronounced over the southwest region where the precipitation spell has high activity during the period. Significant correlation exists between SAM and ISMR, even after removing the effect of El Nino. It indicates that the signals of Indian summer monsoon characteristics can be envisaged to a certain extend using the June SAM index. © 2012 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54874
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: Department of Atmospheric Sciences, Cochin University of Science and Technology, Lakeside Campus, Fine Arts Avenue, Cochin, 682016, India
Recommended Citation:
Viswambharan N.,Mohanakumar K.. Signature of a southern hemisphere extratropical influence on the summer monsoon over India[J]. Climate Dynamics,2013-01-01,41(2)