The Asymmetric Predictive Power of Indian Ocean Dipole for Subsequent Year's ENSO: Role of Atlantic Ocean as an Intermediary

Fan, Lei; Meng, Xing

doi:10.1029/2023gl105525

Cited by 3 publications

(1 citation statement)

References 32 publications

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“…Nevertheless, we found that model experimental results for El Niño (1991, 1994, 1997, 2009), La Niña (1998, 2000, 2016, 2017) and neutral (1990, 1993, 1996, 2013) years are similar (figures not shown). What remains unclear is the relative importance of the two tropical oceans and/or the Indian Ocean on the multi‐decadal modulations of this inter‐basin connection (Fan & Meng, 2023; Feng et al., 2023, 2024; Zhang & Han, 2021; Zhang & Li, 2023). This warrants a thorough investigation in future studies.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Atlantic Warming Enhances the Influence of Atlantic Niño on ENSO

Wang,

He,

Luo

et al. 2024

Geophysical Research Letters

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The influence of Atlantic Niño on the following El Niño–Southern Oscillation becomes significant since mid‐1970s. However, exact mechanisms for this inter‐decadal change are still unclear. Here, we perform a set of model pacemaker experiments to probe the relative contributions of the changes in the Atlantic Niño itself and the mean‐state under global warming. The results suggest that the warmer background of the tropical Atlantic plays an essential role in enhancing local mean precipitation, inducing stronger divergence and low‐level easterlies in the Pacific. Under a favorable condition in the Pacific, even a weak Atlantic Niño‐related warming could promote the development of La Niña through cross‐basin Walker circulation and the Indian Ocean‐relayed Kelvin wave response. In contrast, the Atlantic Niño pattern change itself induces feeble convection anomalies in the western Atlantic, which cannot induce significant atmospheric response in the Pacific. These results imply an important modulation of global warming on the inter‐basin connection.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Atlantic Warming Enhances the Influence of Atlantic Niño on ENSO

Wang,

He,

Luo

et al. 2024

Geophysical Research Letters

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Indian summer monsoon rainfall response to two distinct evolutions of La Niña events

Sharma,

Ratna,

Pai

et al. 2024

Intl Journal of Climatology

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This study examines the asymmetry in the Indian summer monsoon rainfall (ISMR) response over India and its four homogeneous regions to two distinct types of temporal evolution in La Niña. We have shown this uneven response by analysing the large‐scale dynamics over tropical Indo‐Pacific region for the period 1951–2022. We have identified two types of La Niña events during monsoon season (June–September) based on whether they evolved from El Niño or La Niña from preceding boreal winter season (December–February). India receives significantly more (less) rainfall during La Niña years, when it was preceded by El Niño (La Niña) in the preceding winter. We further observed the spatial diversity of rainfall over India with a northeast–southwest dipole pattern. When La Niña years were preceded by El Niño, positive surface pressure anomaly over west‐north Pacific, low‐level westerlies and moisture transport favoured the rainfall over south peninsula and west‐central India. Whereas moisture divergence associated with anomalous lower‐tropospheric anticyclone over west‐north Pacific suppressed the rainfall over Indo‐Gangetic plains. However, when La Niña years were preceded by La Niña in winter, the absence of westerlies and weak moisture transport subdued the rainfall over south peninsula and west‐central India. At the same time, moisture convergence and a greater number of monsoon depressions favoured rainfall over north‐west India. This study also looked at how well eight Copernicus Climate Change Service (C3S) models predicted ISMR and SST for two types of La Niña with April initial conditions during the period 1993–2016. Models were able to capture the spatial pattern of SST anomalies over Indo‐Pacific Ocean, but all models could not capture the spatial pattern of ISMR. However, in terms of intensity, six out of eight models could predict more (less) ISMR when it was preceded by El Niño (La Niña), coinciding with the observed anomaly.

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Indian Ocean Dipole intensifies Benguela Niño through Congo River discharge

McPhaden,

Jarugula,

Aroucha

et al. 2024

Commun Earth Environ

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Benguela Niños are episodes of unusual El Niño-like warming in the upwelling zone off the coast of southwest Africa, with consequential impacts on marine ecosystems, coastal fisheries and regional weather. The strongest Benguela Niño in the past 40 years occurred in February–April 1995 with local sea surface temperature anomalies up to 4 °C off the coast of Angola and Namibia. Here, we show that a strong Indian Ocean Dipole in September–November 1994 helped boost the amplitude of the 1995 Benguela Niño through a land bridge involving Congo River discharge. We use atmospheric, oceanic, and hydrological data to demonstrate the sequential linkage between Indian Ocean Dipole development, unusually high rainfall in the Congo River basin, high Congo River discharge, low salinity near the Congo River mouth, and southward advection of this low salinity water into the Benguela upwelling region. The low salinity water isolated the surface mixed layer from the thermocline, which limited vertical mixing with colder subsurface waters and led to enhanced sea surface temperature warming. We also discuss how other Indian Ocean Dipole events may have similarly affected subsequent Benguela Niños and the possibility that Indian Ocean Dipole impacts on Benguela Niños may become more prominent in the future.

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The Asymmetric Predictive Power of Indian Ocean Dipole for Subsequent Year's ENSO: Role of Atlantic Ocean as an Intermediary

Cited by 3 publications

References 32 publications

Atlantic Warming Enhances the Influence of Atlantic Niño on ENSO

Atlantic Warming Enhances the Influence of Atlantic Niño on ENSO

Indian summer monsoon rainfall response to two distinct evolutions of La Niña events

Indian Ocean Dipole intensifies Benguela Niño through Congo River discharge

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