气候变化领域集成服务门户(CCPortal): Remote influences on the Indian monsoon low-level jet intraseasonal variations

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DOI	10.1007/s00382-019-05108-1
	Remote influences on the Indian monsoon low-level jet intraseasonal variations
	Swathi M.S.; Izumo T.; Lengaigne M.; Vialard J.; Kumar M.R.R.
发表日期	2020
ISSN	0930-7575
起始页码	2221
结束页码	2236
卷号	54
英文摘要	A strong low-level jet (LLJ), also known as the Findlater jet, develops over the Arabian Sea during the Indian summer monsoon. This jet is an essential source of moisture for monsoonal rainfall over the densely-populated Indian subcontinent and is a key contributor to the Indian Ocean oceanic productivity by sustaining the western Arabian Sea upwelling systems. The LLJ intensity fluctuates intraseasonally within the ~ 20- to 90-day band, in relation with the northward-propagating active and break phases of the Indian summer monsoon. Our observational analyses reveal that these large-scale regional convective perturbations only explain about half of the intraseasonal LLJ variance, the other half being unrelated to large-scale convective perturbations over the Indian Ocean. We show that convective fluctuations in two regions outside the Indian Ocean can remotely force a LLJ intensification, four days later. Enhanced atmospheric deep convection over the northwestern tropical Pacific yields westerly wind anomalies that propagate westward to the Arabian Sea as baroclinic atmospheric Rossby Waves. Suppressed convection over the eastern Pacific/North American monsoon region yields westerly wind anomalies that propagate eastward to the Indian Ocean as dry baroclinic equatorial Kelvin waves. Those largely independent remote influences jointly explain ~ 40% of the intraseasonal LLJ variance that is not related to convective perturbations over the Indian Ocean (i.e. ~ 20% of the total), with the northwestern Pacific contributing twice as much as the eastern Pacific. Taking into account these two remote influences should thus enhance the ability to predict the LLJ. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
语种	英语
scopus关键词	air-sea interaction; atmospheric convection; jet flow; Kelvin wave; monsoon; perturbation; seasonal variation; upwelling; Arabian Sea; Indian Ocean
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/145577
作者单位	CSIR-National Institute of Oceanography, Goa, India; Sorbonne Universités (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, LOCEAN Laboratory, IPSL, Paris, France; Indo-French Cell for Water Sciences, IISc-NIO-IITM–IRD Joint International Laboratory, NIO, Goa, India
推荐引用方式 GB/T 7714	Swathi M.S.,Izumo T.,Lengaigne M.,et al. Remote influences on the Indian monsoon low-level jet intraseasonal variations[J],2020,54.
APA	Swathi M.S.,Izumo T.,Lengaigne M.,Vialard J.,&Kumar M.R.R..(2020).Remote influences on the Indian monsoon low-level jet intraseasonal variations.Climate Dynamics,54.
MLA	Swathi M.S.,et al."Remote influences on the Indian monsoon low-level jet intraseasonal variations".Climate Dynamics 54(2020).