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DOI	10.1007/s00382-018-4397-7
	Contrasting trends in southwest monsoon rainfall over the Western Ghats region of India
	Varikoden H.; Revadekar J.V.; Kuttippurath J.; Babu C.A.
发表日期	2019
ISSN	0930-7575
起始页码	4557
结束页码	4566
卷号	52 期号:2020-07-08
英文摘要	This study presents the contrasting trends of rainfall in the northern and southern Western Ghats (WG) and examines possible reasons for the phenomenon. The WG is one of the important mountain ranges that run parallel to the west coast of India. The mountain chain lies almost perpendicular to the low level jet stream (LLJ) and hence, receives about three times the average rainfall in India. The onset of southwest monsoon also occurs at this region, and thus WG plays a key role in regulating Indian climate through regional climate modulations. Therefore, detecting changes in the rainfall in WG is necessary to identify changes in regional climate. Here, we examine the features of rainfall received and reasons for the observed rainfall patterns in the northern and southern WG. In general, the rainfall peaks are observed in low elevated areas with high inter-annual variability. We find an increase (decrease) southwest monsoon rainfall of about 1.6 mm day −1 decade −1 in certain pockets of the northern (southern) WG. However, an average trend of + 0.3 (− 0.39) mm day −1 decade −1 is estimated in the northern (southern) WG for the 1931–2015 period. Our analyses reveal that this contrasting trend in rainfall (i.e. positive in the north and negative in the south WG) is due to the northward movement of LLJ; from 10°N to 15°N. This shift in LLJ is triggered by an abnormal increase in the surface temperature of the northern Arabian Sea and tropospheric temperature of the north India in the recent decades. The warming helped the LLJ core to move northwards and that weakened (strengthened) the westerly winds over the southern (northern) WG to significantly change the pattern of southwest monsoon rainfall. Henceforth, this study cautions the changes in the rainfall pattern over WG, which can have significant long-term implications for regional climate change. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Linear trend; Low level jet stream; Monsoon rainfall; SST; Western Ghats
语种	英语
scopus关键词	annual variation; climate change; jet stream; monsoon; mountain region; rainfall; regional climate; sea surface temperature; trend analysis; India; Western Ghats
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146412
作者单位	Indian Institute of Tropical Meteorology, Pashan, Pune, 411008, India; CORAL, Indian Institute of Technology Kharagpur, Kharagpur, India; Cochin University of Science and Technology, Kochi, India
推荐引用方式 GB/T 7714	Varikoden H.,Revadekar J.V.,Kuttippurath J.,et al. Contrasting trends in southwest monsoon rainfall over the Western Ghats region of India[J],2019,52(2020-07-08).
APA	Varikoden H.,Revadekar J.V.,Kuttippurath J.,&Babu C.A..(2019).Contrasting trends in southwest monsoon rainfall over the Western Ghats region of India.Climate Dynamics,52(2020-07-08).
MLA	Varikoden H.,et al."Contrasting trends in southwest monsoon rainfall over the Western Ghats region of India".Climate Dynamics 52.2020-07-08(2019).