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DOI	10.1007/s00382-021-06060-9
	Dynamics of dry air intrusion over India during summer monsoon breaks
	Singh, Rahul; Sandeep, S.
通讯作者	Sandeep, S (corresponding author), Indian Inst Technol Delhi, Ctr Atmospher Sci, New Delhi 110016, India.
来源期刊	CLIMATE DYNAMICS
ISSN	0930-7575
EISSN	1432-0894
出版年	2021-11
英文摘要	The dry air intrusion over India during summer monsoon break phases is well known. It has been argued that this dry air originates over the desert regions of West Asia. Here, we show that a reservoir of saturation deficit air exists over the western and northern Arabian Sea during the summer monsoon season. The monsoon low-level jet (LLJ) that transports the moisture to continental India in the active phase of monsoon, transports the dry air to northern and central India during the break phase. The LLJ undergoes a weakening and broadening before the monsoon break phase in response to increased barotropic instability. The broadening of LLJ leads to an intensification of zonal flow in the poleward flanks and a weakening at the core. The development of a positive meridional SST gradient over the northern Arabian Sea favours an increase in the low-level zonal flow in the north, which advects the moist deficit air across northwest India. The dry air intrusion results in enhanced static stability over northern and central India and strong suppression of convection. Further, the enhanced static stability weakens zonal flow from the northern Arabian Sea region and leads to the demise of the dry air intrusion. Thus, internal mechanisms are responsible for the dry air intrusion over India and its termination during the break phase of the summer monsoon. An index for the dry air intrusion is constructed based on the saturation deficit transport. This dry air intrusion index is used to identify the dry air intrusion events during monsoon breaks during the 1981-2014 period. The statistics show that there were 34 (4) monsoon breaks with (without) dry air intrusion during 1981-2014 period. We also note that the dry air intrusion and the monsoon breaks are happening simultaneously, suggesting that it is difficult to establish a cause-effect relationship.
英文关键词	Indian summer monsoon Dry air intrusion Low level jet
类型	Article ; Early Access
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000722972400002
WOS关键词	SOUTH ASIAN MONSOON ; ATLANTIC ZONAL MODE ; INTRASEASONAL OSCILLATIONS ; OCEAN DIPOLE ; VARIABILITY ; RESOLUTION ; PRECIPITATION ; CIRCULATION ; DROUGHT ; PROPAGATION
WOS类目	Meteorology & Atmospheric Sciences
WOS研究方向	Meteorology & Atmospheric Sciences
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/374638
作者单位	[Singh, Rahul; Sandeep, S.] Indian Inst Technol Delhi, Ctr Atmospher Sci, New Delhi 110016, India
推荐引用方式 GB/T 7714	Singh, Rahul,Sandeep, S.. Dynamics of dry air intrusion over India during summer monsoon breaks[J],2021.
APA	Singh, Rahul,&Sandeep, S..(2021).Dynamics of dry air intrusion over India during summer monsoon breaks.CLIMATE DYNAMICS.
MLA	Singh, Rahul,et al."Dynamics of dry air intrusion over India during summer monsoon breaks".CLIMATE DYNAMICS (2021).