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DOI	10.1007/s00382-024-07245-8
	Variability of summer monsoon depressions over the Bay of Bengal with special emphasis on El Niño cycle
	Chowdary, Jasti S.; Mahendra, Nimmakanti; Konda, Gopinadh; Chilukoti, Nagaraju; Parekh, Anant; Gnanaseelan, C.
发表日期	2024
ISSN	0930-7575
EISSN	1432-0894
英文摘要	Interannual variability of summer monsoon depressions (MDs) over the Bay of Bengal (BoB) is investigated with special emphasis on developing and decaying El Ni & ntilde;o phases during the period 1979-2020. Previous studies have overlooked the relationship between MDs frequency and El Ni & ntilde;o phenomena, despite of their stronger association with Indian Summer Monsoon (ISM) rainfall. Our analysis revealed that the number of MDs has reduced remarkably by a factor of 2 during El Ni & ntilde;o decay summers (more than half) as compared to climatology and in fact, no such decline is depicted in developing El Ni & ntilde;o years. The strong easterlies extending from the southern flank of the Western North Pacific (WNP) anticyclone to the southern BoB cause negative low-level vorticity anomalies and reduce the Barotropic instability during El Ni & ntilde;o decay summers. These conditions are unfavourable for the formation of MDs in the BoB. It is also noted that the Genesis Potential Parameter (GPP) for the MDs over the BoB and WNP region is weaker in the El Ni & ntilde;o decay summers compared to developing El Ni & ntilde;o and normal years. Moreover, during the El Ni & ntilde;o decay summers less number of Tropical Cyclones (TCs) over WNP due to weak GPP, reduced the chances of westward propagating remnants of TCs from the Philippine Sea to the BoB, which is not favourable for the formation of MDs. Essentially, the reduction in the frequency of MDs would influence the seasonal rainfall distribution over the Indian subcontinent and largely impacts the regional agriculture activities and water management sector. Further, the Indo-western Pacific capacitor (IPOC) effect, which is strongly tied to decaying El Ni & ntilde;o phase plays a critical role in altering the number of MDs by maintaining WNP anticyclone. Thus, predicting IPOC pattern during the decay phase of El Ni & ntilde;o would provide useful insights on a number of MDs and ISM rainfall prediction.
英文关键词	Monsoon Depressions; Sea Surface Temperature; Bay of Bengal; El Ni & ntilde;o; Western north Pacific; Anticyclone
语种	英语
WOS研究方向	Meteorology & Atmospheric Sciences
WOS类目	Meteorology & Atmospheric Sciences
WOS记录号	WOS:001209376200001
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/305569
作者单位	Ministry of Earth Sciences (MoES) - India; Indian Institute of Tropical Meteorology (IITM); National Institute of Technology (NIT System); National Institute of Technology Rourkela
推荐引用方式 GB/T 7714	Chowdary, Jasti S.,Mahendra, Nimmakanti,Konda, Gopinadh,et al. Variability of summer monsoon depressions over the Bay of Bengal with special emphasis on El Niño cycle[J],2024.
APA	Chowdary, Jasti S.,Mahendra, Nimmakanti,Konda, Gopinadh,Chilukoti, Nagaraju,Parekh, Anant,&Gnanaseelan, C..(2024).Variability of summer monsoon depressions over the Bay of Bengal with special emphasis on El Niño cycle.CLIMATE DYNAMICS.
MLA	Chowdary, Jasti S.,et al."Variability of summer monsoon depressions over the Bay of Bengal with special emphasis on El Niño cycle".CLIMATE DYNAMICS (2024).