A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean
The meridional heat transport (MHT) in the North Atlantic is critically important to climate variability and the global overturning circulation. A wide range of ocean processes contribute to North Atlantic MHT, ranging from basin-scale overturning and gyre motions to mesoscale instabilities (such as...
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ftdoajarticles:oai:doaj.org/article:0e5fcae8b420472582dfb31f10b3dd26 2023-05-15T17:30:11+02:00 A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean A. Delman T. Lee 2020-08-01T00:00:00Z https://doi.org/10.5194/os-16-979-2020 https://doaj.org/article/0e5fcae8b420472582dfb31f10b3dd26 EN eng Copernicus Publications https://os.copernicus.org/articles/16/979/2020/os-16-979-2020.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-16-979-2020 1812-0784 1812-0792 https://doaj.org/article/0e5fcae8b420472582dfb31f10b3dd26 Ocean Science, Vol 16, Pp 979-995 (2020) Geography. Anthropology. Recreation G Environmental sciences GE1-350 article 2020 ftdoajarticles https://doi.org/10.5194/os-16-979-2020 2022-12-31T04:18:01Z The meridional heat transport (MHT) in the North Atlantic is critically important to climate variability and the global overturning circulation. A wide range of ocean processes contribute to North Atlantic MHT, ranging from basin-scale overturning and gyre motions to mesoscale instabilities (such as eddies). However, previous analyses of “eddy” MHT in the region have mostly focused on the contributions of time-variable velocity and temperature, rather than considering the association of MHT with distinct spatial scales within the basin. In this study, a zonal spatial-scale decomposition separates large-scale from mesoscale velocity and temperature contributions to MHT, in order to characterize the physical processes driving MHT. Using this approach, we found that the mesoscale contributions to the time-mean and interannual/decadal (ID) variability of MHT in the latitude range 39–45 ∘ N are larger than large-scale horizontal contributions, though smaller than the overturning contributions. Considering the 40 ∘ N transect as a case study, large-scale ID variability is mostly generated close to the western boundary. In contrast, most ID MHT variability associated with mesoscales originates in two distinct regions: a western boundary region (70–60 ∘ W) associated with 1- to 4-year interannual variations and an interior region (50–35 ∘ W) associated with decadal variations. Surface eddy kinetic energy is not a reliable indicator of high MHT episodes, but the large-scale meridional temperature gradient is an important factor, by influencing the local temperature variance as well as the local correlation of velocity and temperature. Most of the mesoscale contribution to MHT at 40 ∘ N is associated with transient and propagating processes, but stationary mesoscale structures explain most of the mesoscale MHT south of the Gulf Stream separation, highlighting the differences between the temporal and spatial decomposition of meridional temperature fluxes. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Ocean Science 16 4 979 995 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
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Geography. Anthropology. Recreation G Environmental sciences GE1-350 A. Delman T. Lee A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean |
topic_facet |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
description |
The meridional heat transport (MHT) in the North Atlantic is critically important to climate variability and the global overturning circulation. A wide range of ocean processes contribute to North Atlantic MHT, ranging from basin-scale overturning and gyre motions to mesoscale instabilities (such as eddies). However, previous analyses of “eddy” MHT in the region have mostly focused on the contributions of time-variable velocity and temperature, rather than considering the association of MHT with distinct spatial scales within the basin. In this study, a zonal spatial-scale decomposition separates large-scale from mesoscale velocity and temperature contributions to MHT, in order to characterize the physical processes driving MHT. Using this approach, we found that the mesoscale contributions to the time-mean and interannual/decadal (ID) variability of MHT in the latitude range 39–45 ∘ N are larger than large-scale horizontal contributions, though smaller than the overturning contributions. Considering the 40 ∘ N transect as a case study, large-scale ID variability is mostly generated close to the western boundary. In contrast, most ID MHT variability associated with mesoscales originates in two distinct regions: a western boundary region (70–60 ∘ W) associated with 1- to 4-year interannual variations and an interior region (50–35 ∘ W) associated with decadal variations. Surface eddy kinetic energy is not a reliable indicator of high MHT episodes, but the large-scale meridional temperature gradient is an important factor, by influencing the local temperature variance as well as the local correlation of velocity and temperature. Most of the mesoscale contribution to MHT at 40 ∘ N is associated with transient and propagating processes, but stationary mesoscale structures explain most of the mesoscale MHT south of the Gulf Stream separation, highlighting the differences between the temporal and spatial decomposition of meridional temperature fluxes. |
format |
Article in Journal/Newspaper |
author |
A. Delman T. Lee |
author_facet |
A. Delman T. Lee |
author_sort |
A. Delman |
title |
A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean |
title_short |
A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean |
title_full |
A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean |
title_fullStr |
A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean |
title_full_unstemmed |
A new method to assess mesoscale contributions to meridional heat transport in the North Atlantic Ocean |
title_sort |
new method to assess mesoscale contributions to meridional heat transport in the north atlantic ocean |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/os-16-979-2020 https://doaj.org/article/0e5fcae8b420472582dfb31f10b3dd26 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Ocean Science, Vol 16, Pp 979-995 (2020) |
op_relation |
https://os.copernicus.org/articles/16/979/2020/os-16-979-2020.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-16-979-2020 1812-0784 1812-0792 https://doaj.org/article/0e5fcae8b420472582dfb31f10b3dd26 |
op_doi |
https://doi.org/10.5194/os-16-979-2020 |
container_title |
Ocean Science |
container_volume |
16 |
container_issue |
4 |
container_start_page |
979 |
op_container_end_page |
995 |
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