Projected response of the Indian Ocean Dipole to greenhouse warming

Cai, Wenju; Zheng, Xiao‐Tong; Weller, Evan; Collins, Matthew; Cowan, Tim; Lengaigne, Matthieu; Yu, Weidong; Yamagata, Toshio

doi:10.1038/ngeo2009

Cited by 214 publications

(233 citation statements)

References 92 publications

Supporting

Mentioning

218

Contrasting

Order By: Relevance

“…8d). This upward trend, however, appears in some SST datasets but not in others, highlighting the uncertainties in these trends (Cai et al 2013). With frequently occurring intensified positive IOD events, we expect enhanced and more frequent sea level rise in the thermocline ridge region and sea level fall in the eastern basin during boreal fall (Fig.…”

Section: Iod-related Sea Level Patternsmentioning

confidence: 99%

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

et al. 2016

View full text Add to dashboard Cite

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth's climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modes and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this paper, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR.

show abstract

Section: Iod-related Sea Level Patternsmentioning

confidence: 99%

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Our results suggest that part of the weaker WCI oxycline depth response during negative IOD may be explained by the weaker wind stress anomalies at the STI associated with negative IOD events. This weaker wind amplitude could simply be related to the tendency of negative IOD events to be weaker than their positive counterpart (Saji and Yamagata, 2003;Hong et al, 2008;Cai et al, 2013) or to asymmetries in the spatial patterns of winds associated with the nonlinear response of deep atmospheric convection to SST anomalies of each phase of the IOD. A more precise understanding of this asymmetry would require an in-depth investigation of the processes that control the wind variations at the STI and the thermocline along the WCI in response to positive and negative IOD events.…”

Section: Influence Of the Iod On The Interannual Oxygen Variability Amentioning

confidence: 99%

Positive Indian Ocean Dipole events prevent anoxia off the west coast of India

et al. 2017

Self Cite

View full text Add to dashboard Cite

Abstract. The seasonal upwelling along the west coast of India (WCI) brings nutrient-rich, oxygen-poor subsurface waters to the continental shelf, favoring very low oxygen concentrations in the surface waters during late boreal summer and fall. This yearly-recurring coastal hypoxia is more severe during some years, leading to coastal anoxia that has strong impacts on the living resources. In the present study, we analyze a 1/4 • resolution coupled physical-biogeochemical regional oceanic simulation over the 1960-2012 period to investigate the physical processes influencing the oxycline interannual variability off the WCI, that being a proxy for the variability on the shelf in our model. Our analysis indicates a tight relationship between the oxycline and thermocline variations in this region on both seasonal and interannual timescales, thereby revealing a strong physical control of the oxycline variability. As in observations, our model exhibits a shallow oxycline and thermocline during fall that combines with interannual variations to create a window of opportunity for coastal anoxic events. We further demonstrate that the boreal fall oxycline fluctuations off the WCI are strongly related to the Indian Ocean Dipole (IOD), with an asymmetric influence of its positive and negative phases. Positive IODs are associated with easterly wind anomalies near the southern tip of India. These winds force downwelling coastal Kelvin waves that propagate along the WCI and deepen the thermocline and oxycline there, thus preventing the occurrence of coastal anoxia. On the other hand, negative IODs are associated with WCI thermocline and oxycline anomalies of opposite sign but of smaller amplitude, so that the negative or neutral IOD phases are necessary but not the sufficient condition for coastal anoxia. As the IODs generally start developing in summer, these findings suggest some predictability to the occurrence of coastal anoxia off the WCI a couple of months ahead.

show abstract

“…Others (e.g., Yamagata et al 2003;Ashok et al 2003;Behera et al 2006) claim that the IOD is an intrinsic mode of the Indian Ocean and pointed to cases of strong IOD events emerging in the absence of El Niño/La Niña events. Establishing the independence of the highly correlated IOD and ENSO events through classical methods such as empirical orthogonal function (EOF) analysis is far from straightforward, and despite extensive research on IOD dynamics and climatic impacts (e.g., Ashok et al 2007;Manatsa et al 2008;Cai et al 2012Cai et al , 2013Pepler et al 2014), there is no consensus on whether it is an intrinsic mode of Indian Ocean variability or a regional manifestation of ENSO. Therefore, alternative ways of reexamining its nature should still be sought.…”

Section: Introductionmentioning

confidence: 99%