What Determines the Lagged ENSO Response in the South‐West Indian Ocean?
Abstract Oceanic Rossby waves can propagate climate signals over considerable distances over long timescales. Using a long simulation from a coupled climate model, we examine oceanic and mixed atmosphere‐ocean teleconnections to the south‐western Indian Ocean (SWIO) associated with Rossby waves exci...
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| Format: | Article |
| Language: | English |
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Wiley
2021-03-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2020GL091958 |
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| author | M. D. Eabry A. S. Taschetto A. M. Maharaj A. Sen Gupta |
| author_facet | M. D. Eabry A. S. Taschetto A. M. Maharaj A. Sen Gupta |
| author_sort | M. D. Eabry |
| collection | DOAJ |
| description | Abstract Oceanic Rossby waves can propagate climate signals over considerable distances over long timescales. Using a long simulation from a coupled climate model, we examine oceanic and mixed atmosphere‐ocean teleconnections to the south‐western Indian Ocean (SWIO) associated with Rossby waves excited by the El Niño‐Southern Oscillation (ENSO). Reconstruction of propagating ENSO‐induced sea‐level anomalies from the simulation using an optimized linear wave model with dissipation highlights the prominent role of baroclinic, rather than barotropic, Rossby waves in modulating sea‐surface heights. Between 9.5° and 18.5°S, El Niño‐associated anomalous anticyclonic wind‐stress fields initiate downwelling Rossby waves, potentially influencing SWIO regional climate around 1–4 seasons after El Niño peak, while also destructively interfering with upwelling waves triggered on the eastern boundary by oceanic teleconnections. Further south, weaker ENSO winds, dissipation, non‐linear processes, and interference from higher‐mode Rossby waves limit ENSO influences in the SWIO. In the model, ENSO‐associated predictability is therefore constrained by the “atmospheric” rather than “oceanic” bridge. |
| format | Article |
| id | doaj-art-fb0dbd9f830c40e58028fd71f14da96c |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2021-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-fb0dbd9f830c40e58028fd71f14da96c2025-08-20T03:48:43ZengWileyGeophysical Research Letters0094-82761944-80072021-03-01486n/an/a10.1029/2020GL091958What Determines the Lagged ENSO Response in the South‐West Indian Ocean?M. D. Eabry0A. S. Taschetto1A. M. Maharaj2A. Sen Gupta3Climate Change Research Centre and ARC Centre of Excellence for Climate Extremes University of New South Wales Sydney NSW AustraliaClimate Change Research Centre and ARC Centre of Excellence for Climate Extremes University of New South Wales Sydney NSW AustraliaClimate Change Research Centre and ARC Centre of Excellence for Climate Extremes University of New South Wales Sydney NSW AustraliaClimate Change Research Centre and ARC Centre of Excellence for Climate Extremes University of New South Wales Sydney NSW AustraliaAbstract Oceanic Rossby waves can propagate climate signals over considerable distances over long timescales. Using a long simulation from a coupled climate model, we examine oceanic and mixed atmosphere‐ocean teleconnections to the south‐western Indian Ocean (SWIO) associated with Rossby waves excited by the El Niño‐Southern Oscillation (ENSO). Reconstruction of propagating ENSO‐induced sea‐level anomalies from the simulation using an optimized linear wave model with dissipation highlights the prominent role of baroclinic, rather than barotropic, Rossby waves in modulating sea‐surface heights. Between 9.5° and 18.5°S, El Niño‐associated anomalous anticyclonic wind‐stress fields initiate downwelling Rossby waves, potentially influencing SWIO regional climate around 1–4 seasons after El Niño peak, while also destructively interfering with upwelling waves triggered on the eastern boundary by oceanic teleconnections. Further south, weaker ENSO winds, dissipation, non‐linear processes, and interference from higher‐mode Rossby waves limit ENSO influences in the SWIO. In the model, ENSO‐associated predictability is therefore constrained by the “atmospheric” rather than “oceanic” bridge.https://doi.org/10.1029/2020GL091958atmospheric bridgeEl NiñoIndian Oceanoceanic bridgeRossby waves |
| spellingShingle | M. D. Eabry A. S. Taschetto A. M. Maharaj A. Sen Gupta What Determines the Lagged ENSO Response in the South‐West Indian Ocean? Geophysical Research Letters atmospheric bridge El Niño Indian Ocean oceanic bridge Rossby waves |
| title | What Determines the Lagged ENSO Response in the South‐West Indian Ocean? |
| title_full | What Determines the Lagged ENSO Response in the South‐West Indian Ocean? |
| title_fullStr | What Determines the Lagged ENSO Response in the South‐West Indian Ocean? |
| title_full_unstemmed | What Determines the Lagged ENSO Response in the South‐West Indian Ocean? |
| title_short | What Determines the Lagged ENSO Response in the South‐West Indian Ocean? |
| title_sort | what determines the lagged enso response in the south west indian ocean |
| topic | atmospheric bridge El Niño Indian Ocean oceanic bridge Rossby waves |
| url | https://doi.org/10.1029/2020GL091958 |
| work_keys_str_mv | AT mdeabry whatdeterminesthelaggedensoresponseinthesouthwestindianocean AT astaschetto whatdeterminesthelaggedensoresponseinthesouthwestindianocean AT ammaharaj whatdeterminesthelaggedensoresponseinthesouthwestindianocean AT asengupta whatdeterminesthelaggedensoresponseinthesouthwestindianocean |