Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean.
International audience Westward propagating features, identified as semiannual Rossby waves, have been observed in the southern subtropical Indian Ocean between 20S and 35S. A previous study based on ERS satellite scatterometer wind stress data in this region has shown that the Rossby waves were not...
Published in: | Journal of Marine Research |
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Main Authors: | , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2003
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Online Access: | https://hal.science/hal-00765715 https://doi.org/10.1357/002224003322981110 |
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ftutoulouse3hal:oai:HAL:hal-00765715v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université Toulouse III - Paul Sabatier: HAL-UPS |
op_collection_id |
ftutoulouse3hal |
language |
English |
topic |
Australasia Coastal current Offshore Semiannual variation Month Forcing lead Australia Antarctic Seas Indian Ocean signals sea level latitude phase velocity anomalies Tide gauge Wave propagation Local wind Ekman pumping Forced wave Wind effect Scatterometer Wind satellite ERS Rossby wave [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
Australasia Coastal current Offshore Semiannual variation Month Forcing lead Australia Antarctic Seas Indian Ocean signals sea level latitude phase velocity anomalies Tide gauge Wave propagation Local wind Ekman pumping Forced wave Wind effect Scatterometer Wind satellite ERS Rossby wave [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Birol, Florence Morrow, Rosemary Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean. |
topic_facet |
Australasia Coastal current Offshore Semiannual variation Month Forcing lead Australia Antarctic Seas Indian Ocean signals sea level latitude phase velocity anomalies Tide gauge Wave propagation Local wind Ekman pumping Forced wave Wind effect Scatterometer Wind satellite ERS Rossby wave [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Westward propagating features, identified as semiannual Rossby waves, have been observed in the southern subtropical Indian Ocean between 20S and 35S. A previous study based on ERS satellite scatterometer wind stress data in this region has shown that the Rossby waves were not forced by local Ekman pumping in the ocean interior nor by local variations in wind stress near the Australian coast. In the present study, we investigate a third possible source, in the form of remotely forced semiannual coastal waves propagating along the Australian coast. Altimetric and tide gauge data show consistent semiannual anomalies along the northwestern and western coast, with a phase lag between the northernmost station and about 25S, producing a poleward phase speed of ∼0.4 m s-1. South of the critical latitude for semiannual Rossby wave radiation at 27S, we still observe a significant sea level signal along the coast at the semiannual frequency that appears nearly in phase between the stations. Semiannual sea level anomalies lead the semiannual wind forcing by about one month, confirming that the signal is not locally forced. These semiannual coastal variations are in phase with the offshore radiation of Rossby waves observed between 20S and 35S. We suggest that, south of the critical latitude of 27S, the observed coastal wave signal could interact with the poleward coastal Leeuwin Current and that this wave-current interaction could stimulate nonlinear instabilities of this density-driven current and may be a key mechanism for the Rossby wave radiation in the subtropical Indian Ocean. |
author2 |
Echanges Côte-Large (ECOLA) Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Birol, Florence Morrow, Rosemary |
author_facet |
Birol, Florence Morrow, Rosemary |
author_sort |
Birol, Florence |
title |
Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean. |
title_short |
Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean. |
title_full |
Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean. |
title_fullStr |
Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean. |
title_full_unstemmed |
Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean. |
title_sort |
separation of quasi-semiannual rossby waves from the eastern boundary of the indian ocean. |
publisher |
HAL CCSD |
publishDate |
2003 |
url |
https://hal.science/hal-00765715 https://doi.org/10.1357/002224003322981110 |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 0022-2402 EISSN: 1543-9542 Journal of marine research https://hal.science/hal-00765715 Journal of marine research, 2003, 61 (6), pp.707-723(17). ⟨10.1357/002224003322981110⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1357/002224003322981110 hal-00765715 https://hal.science/hal-00765715 doi:10.1357/002224003322981110 |
op_doi |
https://doi.org/10.1357/002224003322981110 |
container_title |
Journal of Marine Research |
container_volume |
61 |
container_issue |
6 |
container_start_page |
707 |
op_container_end_page |
723 |
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1810494289847779328 |
spelling |
ftutoulouse3hal:oai:HAL:hal-00765715v1 2024-09-15T17:46:17+00:00 Separation of quasi-semiannual Rossby waves from the eastern boundary of the Indian Ocean. Birol, Florence Morrow, Rosemary Echanges Côte-Large (ECOLA) Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) 2003-11 https://hal.science/hal-00765715 https://doi.org/10.1357/002224003322981110 en eng HAL CCSD Yale University info:eu-repo/semantics/altIdentifier/doi/10.1357/002224003322981110 hal-00765715 https://hal.science/hal-00765715 doi:10.1357/002224003322981110 ISSN: 0022-2402 EISSN: 1543-9542 Journal of marine research https://hal.science/hal-00765715 Journal of marine research, 2003, 61 (6), pp.707-723(17). ⟨10.1357/002224003322981110⟩ Australasia Coastal current Offshore Semiannual variation Month Forcing lead Australia Antarctic Seas Indian Ocean signals sea level latitude phase velocity anomalies Tide gauge Wave propagation Local wind Ekman pumping Forced wave Wind effect Scatterometer Wind satellite ERS Rossby wave [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2003 ftutoulouse3hal https://doi.org/10.1357/002224003322981110 2024-06-24T23:59:17Z International audience Westward propagating features, identified as semiannual Rossby waves, have been observed in the southern subtropical Indian Ocean between 20S and 35S. A previous study based on ERS satellite scatterometer wind stress data in this region has shown that the Rossby waves were not forced by local Ekman pumping in the ocean interior nor by local variations in wind stress near the Australian coast. In the present study, we investigate a third possible source, in the form of remotely forced semiannual coastal waves propagating along the Australian coast. Altimetric and tide gauge data show consistent semiannual anomalies along the northwestern and western coast, with a phase lag between the northernmost station and about 25S, producing a poleward phase speed of ∼0.4 m s-1. South of the critical latitude for semiannual Rossby wave radiation at 27S, we still observe a significant sea level signal along the coast at the semiannual frequency that appears nearly in phase between the stations. Semiannual sea level anomalies lead the semiannual wind forcing by about one month, confirming that the signal is not locally forced. These semiannual coastal variations are in phase with the offshore radiation of Rossby waves observed between 20S and 35S. We suggest that, south of the critical latitude of 27S, the observed coastal wave signal could interact with the poleward coastal Leeuwin Current and that this wave-current interaction could stimulate nonlinear instabilities of this density-driven current and may be a key mechanism for the Rossby wave radiation in the subtropical Indian Ocean. Article in Journal/Newspaper Antarc* Antarctic Université Toulouse III - Paul Sabatier: HAL-UPS Journal of Marine Research 61 6 707 723 |