DOI: 10.1007/s00382-016-3233-1
Scopus记录号: 2-s2.0-84974834814
论文题名: Indian summer monsoon rainfall variability in response to differences in the decay phase of El Niño
作者: Chowdary J.S. ; Harsha H.S. ; Gnanaseelan C. ; Srinivas G. ; Parekh A. ; Pillai P. ; Naidu C.V.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2017
卷: 48, 期: 2017-07-08 起始页码: 2707
结束页码: 2727
语种: 英语
英文关键词: El Niño decay phase
; Indian Ocean
; Indian summer monsoon
; Sea surface temperature
; Tropospheric temperature
英文摘要: In general the Indian summer monsoon (ISM) rainfall is near normal or excess during the El Niño decay phase. Nevertheless the impact of large variations in decaying El Niño on the ISM rainfall and circulation is not systematically examined. Based on the timing of El Niño decay with respect to boreal summer season, El Niño decay phases are classified into three types in this study using 142 years of sea surface temperature (SST) data, which are as follows: (1) early-decay (ED; decay during spring), (2) mid-summer decay (MD; decay by mid-summer) and (3) no-decay (ND; no decay in summer). It is observed that ISM rainfall is above normal/excess during ED years, normal during MD years and below normal/deficit in ND years, suggesting that the differences in El Niño decay phase display profound impact on the ISM rainfall. Tropical Indian Ocean (TIO) SST warming, induced by El Niño, decays rapidly before the second half of the monsoon season (August and September) in ED years, but persists up to the end of the season in MD years, whereas TIO warming maintained up to winter in ND case. Analysis reveals the existence of strong sub-seasonal ISM rainfall variations in the summer following El Niño years. During ED years, strong negative SST anomalies develop over the equatorial central-eastern Pacific by June and are apparent throughout the summer season accompanied by anomalous moisture divergence and high sea level pressure (SLP). The associated moisture convergence and low SLP over ISM region favour excess rainfall (mainly from July onwards). This circulation and rainfall anomalies are highly influenced by warm TIO SST and Pacific La Niña conditions in ED years. Convergence of southwesterlies from Arabian Sea and northeasterlies from Bay of Bengal leads to positive rainfall over most part of the Indian subcontinent from August onwards in MD years. ND years are characterized by negative rainfall anomaly spatial pattern and weaker circulation over India throughout the summer season, which are mainly due to persisting El Niño related warm SST anomalies over the Pacific. Atmospheric general circulation model simulation supports our hypothesis that El Niño decay variations modulate ISM rainfall and circulation. © 2016, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53279
Appears in Collections: 过去全球变化的重建
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作者单位: Indian Institute of Tropical Meteorology, Pune, India; Department of Meteorology and Oceanography, Andhra University, Andhra Pradesh, India
Recommended Citation:
Chowdary J.S.,Harsha H.S.,Gnanaseelan C.,et al. Indian summer monsoon rainfall variability in response to differences in the decay phase of El Niño[J]. Climate Dynamics,2017-01-01,48(2017-07-08)