DOI: 10.1007/s00382-011-1100-7
Scopus记录号: 2-s2.0-84861812552
论文题名: Robustness of SST teleconnections and precursory patterns associated with the Indian summer monsoon
作者: Boschat G. ; Terray P. ; Masson S.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2012
卷: 38, 期: 2017-11-12 起始页码: 2143
结束页码: 2165
语种: 英语
英文关键词: ENSO
; Indian Ocean dipole
; Indian summer monsoon
; Sea surface temperature
英文摘要: This work attempts to reconcile in a common and comprehensive framework the various conflicting results found in the literature regarding Indian Summer Monsoon (ISM) rainfall-Sea Surface Temperature (SST) relationships, especially the links with El-Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). To do so, we first examine the linear relationships between ISM rainfall and global SST anomalies during 1950-1976 and 1979-2006 periods. Our results highlight the existence of significant modulations in SST teleconnections and precursory patterns between the first (June-July, JJ) and second part (August-September, AS) of the monsoon. This JJ-AS rainfall dichotomy is more pronounced after the 1976-1977 climate regime shift and tends to blur the global ISM-ENSO signal during the recent period, leading to an apparent weakening of this relationship at the seasonal timescale. Although ISM rainfall in JJ and AS is still strongly linked to ENSO over both periods, the lead-lag relationships between ENSO and AS Indian rainfall have changed during recent decades. Indeed, ENSO variability in the preceding boreal winter has now a significant impact on rainfall variability during the second half of ISM. To evaluate in more details the impact of this JJ-AS dichotomy on the ISM-ENSO-IOD relationships, ISM correlations are also examined separately during El Niño and La Niña years. Results indicate that the early onset of El Niño during boreal spring causes deficient monsoon rainfall in JJ. In response to weaker monsoon winds, warm SST anomalies appear in the west equatorial IO, generating favorable conditions for the development of a positive IOD in AS. Local air-sea processes triggered by the SST anomalies in the eastern node of IOD seem, in turn, to have a more active role on AS rainfall variability, as they may counteract the negative effect of El Niño on ISM rainfall via a modulation of the local Hadley circulation in the eastern IO. The JJ-AS rainfall dichotomy and its recent amplification may then result from an enhancement of these IO feedbacks during recent El Niño years. This explains why, although El Niño events are stronger, a weakening of the ISM-ENSO relationship is observed at the seasonal scale after 1979. Results during La Niña years are consistent with this hypothesis although local processes in the southeast IO now play a more prominent role and act to further modulate ISM rainfall in AS. Finally, our results highlight the existence of a biennal rhythm of the IOD-ENSO-ISM system during the recent period, according to which co-occurring El Niño and positive IOD events tend to be followed by a warming of the IO, a wet ISM during summer and, finally, a La Niña event during the following boreal winter. © 2011 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/55277
Appears in Collections: 过去全球变化的重建
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作者单位: LOCEAN/IPSL, Université Pierre et Marie Curie, BP100-4 place Jussieu, 75252 Paris cedex 05, France; LOCEAN/IPSL, CNRS/IRD/UPMC/MNHN, Université Pierre et Marie Curie, BP100-4 place Jussieu, 75252 Paris cedex 05, France
Recommended Citation:
Boschat G.,Terray P.,Masson S.. Robustness of SST teleconnections and precursory patterns associated with the Indian summer monsoon[J]. Climate Dynamics,2012-01-01,38(2017-11-12)