Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean
We compare estimates of the turbulent dissipation rate, ε, obtained independently from coincident measurements of shear and temperature microstructure in the southeastern Beaufort Sea, a strongly stratified, low‐energy environment. The measurements were collected over 10 days in 2015 by an ocean gli...
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fthzgzmk:oai:publications.hereon.de:36222 2023-06-11T04:07:42+02:00 Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean Scheifele, B. Waterman, S. Merckelbach, L. Carpenter, J.R. 2018 https://publications.hereon.de/id/36222 https://publications.hzg.de/id/36222 http://www.hzg.de/imperia/md/content/gkss/zentrale_einrichtungen/bibliothek/journals/2018/scheifele_36222.pdf en eng AGU https://dx.doi.org/10.1029/2017JC013731 urn:issn:2169-9275 https://publications.hereon.de/id/36222 https://publications.hzg.de/id/36222 http://www.hzg.de/imperia/md/content/gkss/zentrale_einrichtungen/bibliothek/journals/2018/scheifele_36222.pdf info:eu-repo/semantics/openAccess open_access oa_gruen issn:2169-9275 Scheifele, B.; Waterman, S.; Merckelbach, L.; Carpenter, J.R.: Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean. In: Journal of Geophysical Research : Oceans. Vol. 123 (2018) 8, 5459 - 5480. (DOI: /10.1029/2017JC013731) info:eu-repo/semantics/article Zeitschrift Artikel 2018 fthzgzmk https://doi.org/10.1029/2017JC013731 2023-05-28T23:24:42Z We compare estimates of the turbulent dissipation rate, ε, obtained independently from coincident measurements of shear and temperature microstructure in the southeastern Beaufort Sea, a strongly stratified, low‐energy environment. The measurements were collected over 10 days in 2015 by an ocean glider equipped with microstructure instrumentation; they yield 28,575 shear‐derived and 21,577 temperature‐derived ε estimates. We find agreement within a factor of 2 from the two types of estimates when ε exceeds 3 × 10−11 W/kg, a threshold we identify as the noise floor of the shear‐derived estimates. However, the temperature‐derived estimates suggest that the dissipation rate is lower than this threshold in 58% of our observations. Further, the noise floor of the shear measurements artificially skews the statistical distribution of ε below 10−10 W/kg, that is, in 70% of our observations. The shear measurements overestimate portions of the geometric mean vertical profile of ε by more than an order of magnitude and underestimate the overall variability of ε by at least 2 orders of magnitude. We further discuss uncertainties that arise in both temperature‐ and shear‐derived ε estimates in strongly stratified, weakly turbulent conditions, and we demonstrate how turbulence spectra are systematically modified by stratification under these conditions. Using evidence from the temperature‐gradient spectral shapes and from the observed ε distributions, we suggest that the temperature‐derived dissipation rates are reliable to values as small as 2 × 10−12 W/kg, making them preferable for characterizing the turbulent dissipation rates in the weakly turbulent environment of this study. Article in Journal/Newspaper Arctic Arctic Arctic Ocean Beaufort Sea Hereon Publications (Helmholtz-Zentrum) Arctic Arctic Ocean Journal of Geophysical Research: Oceans 123 8 5459 5480 |
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Open Polar |
collection |
Hereon Publications (Helmholtz-Zentrum) |
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fthzgzmk |
language |
English |
description |
We compare estimates of the turbulent dissipation rate, ε, obtained independently from coincident measurements of shear and temperature microstructure in the southeastern Beaufort Sea, a strongly stratified, low‐energy environment. The measurements were collected over 10 days in 2015 by an ocean glider equipped with microstructure instrumentation; they yield 28,575 shear‐derived and 21,577 temperature‐derived ε estimates. We find agreement within a factor of 2 from the two types of estimates when ε exceeds 3 × 10−11 W/kg, a threshold we identify as the noise floor of the shear‐derived estimates. However, the temperature‐derived estimates suggest that the dissipation rate is lower than this threshold in 58% of our observations. Further, the noise floor of the shear measurements artificially skews the statistical distribution of ε below 10−10 W/kg, that is, in 70% of our observations. The shear measurements overestimate portions of the geometric mean vertical profile of ε by more than an order of magnitude and underestimate the overall variability of ε by at least 2 orders of magnitude. We further discuss uncertainties that arise in both temperature‐ and shear‐derived ε estimates in strongly stratified, weakly turbulent conditions, and we demonstrate how turbulence spectra are systematically modified by stratification under these conditions. Using evidence from the temperature‐gradient spectral shapes and from the observed ε distributions, we suggest that the temperature‐derived dissipation rates are reliable to values as small as 2 × 10−12 W/kg, making them preferable for characterizing the turbulent dissipation rates in the weakly turbulent environment of this study. |
format |
Article in Journal/Newspaper |
author |
Scheifele, B. Waterman, S. Merckelbach, L. Carpenter, J.R. |
spellingShingle |
Scheifele, B. Waterman, S. Merckelbach, L. Carpenter, J.R. Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean |
author_facet |
Scheifele, B. Waterman, S. Merckelbach, L. Carpenter, J.R. |
author_sort |
Scheifele, B. |
title |
Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean |
title_short |
Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean |
title_full |
Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean |
title_fullStr |
Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean |
title_full_unstemmed |
Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean |
title_sort |
measuring the dissipation rate of turbulent kinetic energy in strongly stratified, low‐energy environments: a case study from the arctic ocean |
publisher |
AGU |
publishDate |
2018 |
url |
https://publications.hereon.de/id/36222 https://publications.hzg.de/id/36222 http://www.hzg.de/imperia/md/content/gkss/zentrale_einrichtungen/bibliothek/journals/2018/scheifele_36222.pdf |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Arctic Ocean Beaufort Sea |
genre_facet |
Arctic Arctic Arctic Ocean Beaufort Sea |
op_source |
issn:2169-9275 Scheifele, B.; Waterman, S.; Merckelbach, L.; Carpenter, J.R.: Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean. In: Journal of Geophysical Research : Oceans. Vol. 123 (2018) 8, 5459 - 5480. (DOI: /10.1029/2017JC013731) |
op_relation |
https://dx.doi.org/10.1029/2017JC013731 urn:issn:2169-9275 https://publications.hereon.de/id/36222 https://publications.hzg.de/id/36222 http://www.hzg.de/imperia/md/content/gkss/zentrale_einrichtungen/bibliothek/journals/2018/scheifele_36222.pdf |
op_rights |
info:eu-repo/semantics/openAccess open_access oa_gruen |
op_doi |
https://doi.org/10.1029/2017JC013731 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
123 |
container_issue |
8 |
container_start_page |
5459 |
op_container_end_page |
5480 |
_version_ |
1768380861428793344 |