Formation of Anticyclones above Topographic Depressions
AbstractLong-lived anticyclonic eddies (ACs) have been repeatedly observed over several North Atlantic basins characterized by bowl-like topographic depressions. Motivated by these previous findings, the authors conduct numerical simulations of the spindown of eddies initialized in idealized topogra...
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2021
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ftcdlib:oai:escholarship.org:ark:/13030/qt78f5f9b1 2024-09-15T18:22:48+00:00 Formation of Anticyclones above Topographic Depressions Solodoch, Aviv Stewart, Andrew L McWilliams, James C 207 - 228 2021-01-01 application/pdf https://escholarship.org/uc/item/78f5f9b1 https://escholarship.org/content/qt78f5f9b1/qt78f5f9b1.pdf https://doi.org/10.1175/jpo-d-20-0150.1 unknown eScholarship, University of California qt78f5f9b1 https://escholarship.org/uc/item/78f5f9b1 https://escholarship.org/content/qt78f5f9b1/qt78f5f9b1.pdf doi:10.1175/jpo-d-20-0150.1 CC-BY Journal of Physical Oceanography, vol 51, iss 1 North Atlantic Ocean Anticyclones Boundary currents Ocean dynamics Shallow-water equations Topographic effects Oceanography Maritime Engineering article 2021 ftcdlib https://doi.org/10.1175/jpo-d-20-0150.1 2024-06-28T06:28:21Z AbstractLong-lived anticyclonic eddies (ACs) have been repeatedly observed over several North Atlantic basins characterized by bowl-like topographic depressions. Motivated by these previous findings, the authors conduct numerical simulations of the spindown of eddies initialized in idealized topographic bowls. In experiments with one or two isopycnal layers, it is found that a bowl-trapped AC is an emergent circulation pattern under a wide range of parameters. The trapped AC, often formed by repeated mergers of ACs over the bowl interior, is characterized by anomalously low potential vorticity (PV). Several PV segregation mechanisms that can contribute to the AC formation are examined. In one-layer experiments, the dynamics of the AC are largely determined by a nonlinearity parameter ϵ that quantifies the vorticity of the AC relative to the bowl’s topographic PV gradient. The AC is trapped in the bowl for low , but for moderate values () partial PV segregation allows the AC to reside at finite distances from the center of the bowl. For higher , eddies freely cross the topography and the AC is not confined to the bowl. These regimes are characterized across a suite of model experiments using ϵ and a PV homogenization parameter. Two-layer experiments show that the trapped AC can be top or bottom intensified, as determined by the domain-mean initial vertical energy distribution. These findings contrast with previous theories of mesoscale turbulence over topography that predict the formation of a prograde slope current, but do not predict a trapped AC. Article in Journal/Newspaper North Atlantic University of California: eScholarship Journal of Physical Oceanography 51 1 207 228 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
North Atlantic Ocean Anticyclones Boundary currents Ocean dynamics Shallow-water equations Topographic effects Oceanography Maritime Engineering |
spellingShingle |
North Atlantic Ocean Anticyclones Boundary currents Ocean dynamics Shallow-water equations Topographic effects Oceanography Maritime Engineering Solodoch, Aviv Stewart, Andrew L McWilliams, James C Formation of Anticyclones above Topographic Depressions |
topic_facet |
North Atlantic Ocean Anticyclones Boundary currents Ocean dynamics Shallow-water equations Topographic effects Oceanography Maritime Engineering |
description |
AbstractLong-lived anticyclonic eddies (ACs) have been repeatedly observed over several North Atlantic basins characterized by bowl-like topographic depressions. Motivated by these previous findings, the authors conduct numerical simulations of the spindown of eddies initialized in idealized topographic bowls. In experiments with one or two isopycnal layers, it is found that a bowl-trapped AC is an emergent circulation pattern under a wide range of parameters. The trapped AC, often formed by repeated mergers of ACs over the bowl interior, is characterized by anomalously low potential vorticity (PV). Several PV segregation mechanisms that can contribute to the AC formation are examined. In one-layer experiments, the dynamics of the AC are largely determined by a nonlinearity parameter ϵ that quantifies the vorticity of the AC relative to the bowl’s topographic PV gradient. The AC is trapped in the bowl for low , but for moderate values () partial PV segregation allows the AC to reside at finite distances from the center of the bowl. For higher , eddies freely cross the topography and the AC is not confined to the bowl. These regimes are characterized across a suite of model experiments using ϵ and a PV homogenization parameter. Two-layer experiments show that the trapped AC can be top or bottom intensified, as determined by the domain-mean initial vertical energy distribution. These findings contrast with previous theories of mesoscale turbulence over topography that predict the formation of a prograde slope current, but do not predict a trapped AC. |
format |
Article in Journal/Newspaper |
author |
Solodoch, Aviv Stewart, Andrew L McWilliams, James C |
author_facet |
Solodoch, Aviv Stewart, Andrew L McWilliams, James C |
author_sort |
Solodoch, Aviv |
title |
Formation of Anticyclones above Topographic Depressions |
title_short |
Formation of Anticyclones above Topographic Depressions |
title_full |
Formation of Anticyclones above Topographic Depressions |
title_fullStr |
Formation of Anticyclones above Topographic Depressions |
title_full_unstemmed |
Formation of Anticyclones above Topographic Depressions |
title_sort |
formation of anticyclones above topographic depressions |
publisher |
eScholarship, University of California |
publishDate |
2021 |
url |
https://escholarship.org/uc/item/78f5f9b1 https://escholarship.org/content/qt78f5f9b1/qt78f5f9b1.pdf https://doi.org/10.1175/jpo-d-20-0150.1 |
op_coverage |
207 - 228 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Journal of Physical Oceanography, vol 51, iss 1 |
op_relation |
qt78f5f9b1 https://escholarship.org/uc/item/78f5f9b1 https://escholarship.org/content/qt78f5f9b1/qt78f5f9b1.pdf doi:10.1175/jpo-d-20-0150.1 |
op_rights |
CC-BY |
op_doi |
https://doi.org/10.1175/jpo-d-20-0150.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
51 |
container_issue |
1 |
container_start_page |
207 |
op_container_end_page |
228 |
_version_ |
1810462814400151552 |