Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean
International audience The kinetic energy (KE) seasonality has been revealed by satellite altimeters in many oceanic regions. Question about the mechanisms that trigger this seasonality is still challenging. We address this question through the comparison of two numerical simulations. The first one,...
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ftccsdartic:oai:HAL:insu-03682736v1 2023-12-17T10:50:48+01:00 Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean Sasaki, Hideharu Klein, Patrice Sasai, Yoshikazu Qiu, Bo Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) 2017 https://insu.hal.science/insu-03682736 https://insu.hal.science/insu-03682736/document https://insu.hal.science/insu-03682736/file/51110.pdf https://doi.org/10.1007/s10236-017-1083-y en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.1007/s10236-017-1083-y insu-03682736 https://insu.hal.science/insu-03682736 https://insu.hal.science/insu-03682736/document https://insu.hal.science/insu-03682736/file/51110.pdf BIBCODE: 2017OcDyn.67.1195S doi:10.1007/s10236-017-1083-y info:eu-repo/semantics/OpenAccess Ocean Dynamics https://insu.hal.science/insu-03682736 Ocean Dynamics, 2017, 67, pp.1195-1216. ⟨10.1007/s10236-017-1083-y⟩ Submesoscale turbulence Scale interactions Mixed-layer instability High-resolution simulations North Pacific [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2017 ftccsdartic https://doi.org/10.1007/s10236-017-1083-y 2023-11-18T23:45:09Z International audience The kinetic energy (KE) seasonality has been revealed by satellite altimeters in many oceanic regions. Question about the mechanisms that trigger this seasonality is still challenging. We address this question through the comparison of two numerical simulations. The first one, with a 1/10° horizontal grid spacing, 54 vertical levels, represents dynamics of physical scales larger than 50 km. The second one, with a 1/30° grid spacing, 100 vertical levels, takes into account the dynamics of physical scales down to 16 km. Comparison clearly emphasizes in the whole North Pacific Ocean, not only a significant KE increase by a factor up to three, but also the emergence of seasonal variability when the scale range 16-50 km (called submesoscales in this study) is taken into account. But the mechanisms explaining these KE changes display strong regional contrasts. In high KE regions, such the Kuroshio Extension and the western and eastern subtropics, frontal mixed-layer instabilities appear to be the main mechanism for the emergence of submesoscales in winter. Subsequent inverse kinetic energy cascade leads to the KE seasonality of larger scales. In other regions, in particular in subarctic regions, results suggest that the KE seasonality is principally produced by larger-scale instabilities with typical scales of 100 km and not so much by smaller-scale mixed-layer instabilities. Using arguments from geostrophic turbulence, the submesoscale impact in these regions is assumed to strengthen mesoscale eddies that become more coherent and not quickly dissipated, leading to a KE increase. Article in Journal/Newspaper Subarctic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Pacific Ocean Dynamics 67 9 1195 1216 |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
Submesoscale turbulence Scale interactions Mixed-layer instability High-resolution simulations North Pacific [SDU]Sciences of the Universe [physics] |
spellingShingle |
Submesoscale turbulence Scale interactions Mixed-layer instability High-resolution simulations North Pacific [SDU]Sciences of the Universe [physics] Sasaki, Hideharu Klein, Patrice Sasai, Yoshikazu Qiu, Bo Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean |
topic_facet |
Submesoscale turbulence Scale interactions Mixed-layer instability High-resolution simulations North Pacific [SDU]Sciences of the Universe [physics] |
description |
International audience The kinetic energy (KE) seasonality has been revealed by satellite altimeters in many oceanic regions. Question about the mechanisms that trigger this seasonality is still challenging. We address this question through the comparison of two numerical simulations. The first one, with a 1/10° horizontal grid spacing, 54 vertical levels, represents dynamics of physical scales larger than 50 km. The second one, with a 1/30° grid spacing, 100 vertical levels, takes into account the dynamics of physical scales down to 16 km. Comparison clearly emphasizes in the whole North Pacific Ocean, not only a significant KE increase by a factor up to three, but also the emergence of seasonal variability when the scale range 16-50 km (called submesoscales in this study) is taken into account. But the mechanisms explaining these KE changes display strong regional contrasts. In high KE regions, such the Kuroshio Extension and the western and eastern subtropics, frontal mixed-layer instabilities appear to be the main mechanism for the emergence of submesoscales in winter. Subsequent inverse kinetic energy cascade leads to the KE seasonality of larger scales. In other regions, in particular in subarctic regions, results suggest that the KE seasonality is principally produced by larger-scale instabilities with typical scales of 100 km and not so much by smaller-scale mixed-layer instabilities. Using arguments from geostrophic turbulence, the submesoscale impact in these regions is assumed to strengthen mesoscale eddies that become more coherent and not quickly dissipated, leading to a KE increase. |
author2 |
Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Sasaki, Hideharu Klein, Patrice Sasai, Yoshikazu Qiu, Bo |
author_facet |
Sasaki, Hideharu Klein, Patrice Sasai, Yoshikazu Qiu, Bo |
author_sort |
Sasaki, Hideharu |
title |
Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean |
title_short |
Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean |
title_full |
Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean |
title_fullStr |
Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean |
title_full_unstemmed |
Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean |
title_sort |
regionality and seasonality of submesoscale and mesoscale turbulence in the north pacific ocean |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://insu.hal.science/insu-03682736 https://insu.hal.science/insu-03682736/document https://insu.hal.science/insu-03682736/file/51110.pdf https://doi.org/10.1007/s10236-017-1083-y |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Subarctic |
genre_facet |
Subarctic |
op_source |
Ocean Dynamics https://insu.hal.science/insu-03682736 Ocean Dynamics, 2017, 67, pp.1195-1216. ⟨10.1007/s10236-017-1083-y⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1007/s10236-017-1083-y insu-03682736 https://insu.hal.science/insu-03682736 https://insu.hal.science/insu-03682736/document https://insu.hal.science/insu-03682736/file/51110.pdf BIBCODE: 2017OcDyn.67.1195S doi:10.1007/s10236-017-1083-y |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1007/s10236-017-1083-y |
container_title |
Ocean Dynamics |
container_volume |
67 |
container_issue |
9 |
container_start_page |
1195 |
op_container_end_page |
1216 |
_version_ |
1785575881491611648 |