Relative Dispersion in the Antarctic Circumpolar Current
<jats:title>Abstract</jats:title><jats:p>Stirring in the subsurface Southern Ocean is examined using RAFOS float trajectories, collected during the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES), along with particle trajectories from a regional eddy permitt...
Main Authors: | , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Meteorological Society
2021
|
Subjects: | |
Online Access: | https://hdl.handle.net/1721.1/133788 |
id |
ftmit:oai:dspace.mit.edu:1721.1/133788 |
---|---|
record_format |
openpolar |
spelling |
ftmit:oai:dspace.mit.edu:1721.1/133788 2023-06-11T04:06:02+02:00 Relative Dispersion in the Antarctic Circumpolar Current Balwada, Dhruv LaCasce, Joseph H Speer, Kevin G Ferrari, Raffaele 2021-09-16T13:49:19Z application/pdf https://hdl.handle.net/1721.1/133788 en eng American Meteorological Society 10.1175/JPO-D-19-0243.1 Journal of Physical Oceanography https://hdl.handle.net/1721.1/133788 Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Meteorological Society (AMS) Article http://purl.org/eprint/type/JournalArticle 2021 ftmit 2023-05-29T08:37:20Z <jats:title>Abstract</jats:title><jats:p>Stirring in the subsurface Southern Ocean is examined using RAFOS float trajectories, collected during the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES), along with particle trajectories from a regional eddy permitting model. A central question is the extent to which the stirring is local, by eddies comparable in size to the pair separation, or nonlocal, by eddies at larger scales. To test this, we examine metrics based on averaging in time and in space. The model particles exhibit nonlocal dispersion, as expected for a limited resolution numerical model that does not resolve flows at scales smaller than ~10 days or ~20–30 km. The different metrics are less consistent for the RAFOS floats; relative dispersion, kurtosis, and relative diffusivity suggest nonlocal dispersion as they are consistent with the model within error, while finite-size Lyapunov exponents (FSLE) suggests local dispersion. This occurs for two reasons: (i) limited sampling of the inertial length scales and a relatively small number of pairs hinder statistical robustness in time-based metrics, and (ii) some space-based metrics (FSLE, second-order structure functions), which do not average over wave motions and are reflective of the kinetic energy distribution, are probably unsuitable to infer dispersion characteristics if the flow field includes energetic wave motions that do not disperse particles. The relative diffusivity, which is also a space-based metric, allows averaging over waves to infer the dispersion characteristics. Hence, given the error characteristics of the metrics and data used here, the stirring in the DIMES region is likely to be nonlocal at scales of 5–100 km.</jats:p> Article in Journal/Newspaper Antarc* Antarctic Southern Ocean DSpace@MIT (Massachusetts Institute of Technology) Antarctic Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
DSpace@MIT (Massachusetts Institute of Technology) |
op_collection_id |
ftmit |
language |
English |
description |
<jats:title>Abstract</jats:title><jats:p>Stirring in the subsurface Southern Ocean is examined using RAFOS float trajectories, collected during the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES), along with particle trajectories from a regional eddy permitting model. A central question is the extent to which the stirring is local, by eddies comparable in size to the pair separation, or nonlocal, by eddies at larger scales. To test this, we examine metrics based on averaging in time and in space. The model particles exhibit nonlocal dispersion, as expected for a limited resolution numerical model that does not resolve flows at scales smaller than ~10 days or ~20–30 km. The different metrics are less consistent for the RAFOS floats; relative dispersion, kurtosis, and relative diffusivity suggest nonlocal dispersion as they are consistent with the model within error, while finite-size Lyapunov exponents (FSLE) suggests local dispersion. This occurs for two reasons: (i) limited sampling of the inertial length scales and a relatively small number of pairs hinder statistical robustness in time-based metrics, and (ii) some space-based metrics (FSLE, second-order structure functions), which do not average over wave motions and are reflective of the kinetic energy distribution, are probably unsuitable to infer dispersion characteristics if the flow field includes energetic wave motions that do not disperse particles. The relative diffusivity, which is also a space-based metric, allows averaging over waves to infer the dispersion characteristics. Hence, given the error characteristics of the metrics and data used here, the stirring in the DIMES region is likely to be nonlocal at scales of 5–100 km.</jats:p> |
format |
Article in Journal/Newspaper |
author |
Balwada, Dhruv LaCasce, Joseph H Speer, Kevin G Ferrari, Raffaele |
spellingShingle |
Balwada, Dhruv LaCasce, Joseph H Speer, Kevin G Ferrari, Raffaele Relative Dispersion in the Antarctic Circumpolar Current |
author_facet |
Balwada, Dhruv LaCasce, Joseph H Speer, Kevin G Ferrari, Raffaele |
author_sort |
Balwada, Dhruv |
title |
Relative Dispersion in the Antarctic Circumpolar Current |
title_short |
Relative Dispersion in the Antarctic Circumpolar Current |
title_full |
Relative Dispersion in the Antarctic Circumpolar Current |
title_fullStr |
Relative Dispersion in the Antarctic Circumpolar Current |
title_full_unstemmed |
Relative Dispersion in the Antarctic Circumpolar Current |
title_sort |
relative dispersion in the antarctic circumpolar current |
publisher |
American Meteorological Society |
publishDate |
2021 |
url |
https://hdl.handle.net/1721.1/133788 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
American Meteorological Society (AMS) |
op_relation |
10.1175/JPO-D-19-0243.1 Journal of Physical Oceanography https://hdl.handle.net/1721.1/133788 |
op_rights |
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. |
_version_ |
1768377759442141184 |