Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage
Abstract: Submesoscale currents and internal gravity waves achieve an intense turbulent cascade near the ocean surface (0 m – O(100) m depth), which is thought to give rise to significant energy sources and sinks for mesoscale eddies. Here, we characterise the contributions of Non-Wave Currents (NWC...
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2023
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ftcdlib:oai:escholarship.org:ark:/13030/qt1hh5s989 2024-01-07T09:42:56+01:00 Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage Tedesco, PF Baker, LE Naveira Garabato, AC Mazloff, MR Gille, ST Caulfield, CP Mashayek, A 2023-11-08 https://escholarship.org/uc/item/1hh5s989 unknown eScholarship, University of California qt1hh5s989 https://escholarship.org/uc/item/1hh5s989 CC-BY Fluid Mechanics and Thermal Engineering Oceanography Engineering Earth Sciences Maritime Engineering article 2023 ftcdlib 2023-12-11T19:07:42Z Abstract: Submesoscale currents and internal gravity waves achieve an intense turbulent cascade near the ocean surface (0 m – O(100) m depth), which is thought to give rise to significant energy sources and sinks for mesoscale eddies. Here, we characterise the contributions of Non-Wave Currents (NWCs; including eddies and fronts) and Internal Gravity Waves (IGWs; including near-inertial motions, lee waves and the internal wave continuum) to near-surface submesoscale turbulence in the Drake Passage. Using a numerical simulation, we combine Lagrangian filtering and a Helmholtz decomposition to identify NWCs and IGWs and to characterise their dynamics (rotational vs. divergent). We show that NWCs and IGWs contribute in different proportions to the inverse and forward turbulent kinetic energy cascades, based on their dynamics and spatiotemporal scales. Purely rotational NWCs cause most of the inverse cascade, while coupled rotational– divergent components of NWCs and coupled NWC–IGWs cause the forward cascade. The cascade changes direction at a spatial scale at which motions become increasingly divergent. However, the forward cascade is ultimately limited by the motions’ spatiotemporal scales. The bulk of the forward cascade (80 – 95%) is caused by NWCs and IGWs of small spatiotemporal scales (L <10 km; T <6 hours), which are primarily rotational: submesoscale eddies, fronts, and the internal wave continuum. These motions also cause a significant part of the inverse cascade (30%). Our results highlight the requirement for high spatiotemporal resolutions to diagnose the properties and large-scale impacts of near-surface submesoscale turbulence accurately, with significant implications for ocean energy cycle study strategies. Article in Journal/Newspaper Drake Passage University of California: eScholarship Drake Passage |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Fluid Mechanics and Thermal Engineering Oceanography Engineering Earth Sciences Maritime Engineering |
spellingShingle |
Fluid Mechanics and Thermal Engineering Oceanography Engineering Earth Sciences Maritime Engineering Tedesco, PF Baker, LE Naveira Garabato, AC Mazloff, MR Gille, ST Caulfield, CP Mashayek, A Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage |
topic_facet |
Fluid Mechanics and Thermal Engineering Oceanography Engineering Earth Sciences Maritime Engineering |
description |
Abstract: Submesoscale currents and internal gravity waves achieve an intense turbulent cascade near the ocean surface (0 m – O(100) m depth), which is thought to give rise to significant energy sources and sinks for mesoscale eddies. Here, we characterise the contributions of Non-Wave Currents (NWCs; including eddies and fronts) and Internal Gravity Waves (IGWs; including near-inertial motions, lee waves and the internal wave continuum) to near-surface submesoscale turbulence in the Drake Passage. Using a numerical simulation, we combine Lagrangian filtering and a Helmholtz decomposition to identify NWCs and IGWs and to characterise their dynamics (rotational vs. divergent). We show that NWCs and IGWs contribute in different proportions to the inverse and forward turbulent kinetic energy cascades, based on their dynamics and spatiotemporal scales. Purely rotational NWCs cause most of the inverse cascade, while coupled rotational– divergent components of NWCs and coupled NWC–IGWs cause the forward cascade. The cascade changes direction at a spatial scale at which motions become increasingly divergent. However, the forward cascade is ultimately limited by the motions’ spatiotemporal scales. The bulk of the forward cascade (80 – 95%) is caused by NWCs and IGWs of small spatiotemporal scales (L <10 km; T <6 hours), which are primarily rotational: submesoscale eddies, fronts, and the internal wave continuum. These motions also cause a significant part of the inverse cascade (30%). Our results highlight the requirement for high spatiotemporal resolutions to diagnose the properties and large-scale impacts of near-surface submesoscale turbulence accurately, with significant implications for ocean energy cycle study strategies. |
format |
Article in Journal/Newspaper |
author |
Tedesco, PF Baker, LE Naveira Garabato, AC Mazloff, MR Gille, ST Caulfield, CP Mashayek, A |
author_facet |
Tedesco, PF Baker, LE Naveira Garabato, AC Mazloff, MR Gille, ST Caulfield, CP Mashayek, A |
author_sort |
Tedesco, PF |
title |
Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage |
title_short |
Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage |
title_full |
Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage |
title_fullStr |
Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage |
title_full_unstemmed |
Spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the Drake Passage |
title_sort |
spatiotemporal characteristics of the near-surface turbulent cascade at the submesoscale in the drake passage |
publisher |
eScholarship, University of California |
publishDate |
2023 |
url |
https://escholarship.org/uc/item/1hh5s989 |
geographic |
Drake Passage |
geographic_facet |
Drake Passage |
genre |
Drake Passage |
genre_facet |
Drake Passage |
op_relation |
qt1hh5s989 https://escholarship.org/uc/item/1hh5s989 |
op_rights |
CC-BY |
_version_ |
1787424188100771840 |