The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability
Decadal climate predictability in the North Atlantic is largely related to ocean low frequency variability, whose sensitivity to initial conditions is not very well understood. Recently, three-dimensional oceanic temperature anomalies optimally perturbing the North Atlantic Mean Temperature (NAMT) h...
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ftosti:oai:osti.gov:1507092 2023-07-30T04:05:12+02:00 The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability Germe, Agathe Sévellec, Florian Mignot, Juliette Fedorov, Alexey Nguyen, Sébastien Swingedouw, Didier 2022-01-03 application/pdf http://www.osti.gov/servlets/purl/1507092 https://www.osti.gov/biblio/1507092 https://doi.org/10.1007/s00382-017-4016-z unknown http://www.osti.gov/servlets/purl/1507092 https://www.osti.gov/biblio/1507092 https://doi.org/10.1007/s00382-017-4016-z doi:10.1007/s00382-017-4016-z 54 ENVIRONMENTAL SCIENCES 2022 ftosti https://doi.org/10.1007/s00382-017-4016-z 2023-07-11T09:32:41Z Decadal climate predictability in the North Atlantic is largely related to ocean low frequency variability, whose sensitivity to initial conditions is not very well understood. Recently, three-dimensional oceanic temperature anomalies optimally perturbing the North Atlantic Mean Temperature (NAMT) have been computed via an optimization procedure using a linear adjoint to a realistic ocean general circulation model. The spatial pattern of the identified perturbations, localized in the North Atlantic, has the largest magnitude between 1000 and 4000 m depth. In the present study, the impacts of these perturbations on NAMT, on the Atlantic meridional overturning circulation (AMOC), and on climate in general are investigated in a global coupled model that uses the same ocean model as was used to compute the three-dimensional optimal perturbations. In the coupled model, these perturbations induce AMOC and NAMT anomalies peaking after 5 and 10 years, respectively, generally consistent with the ocean-only linear predictions. To further understand their impact, their magnitude was varied in a broad range. For initial perturbations with a magnitude comparable to the internal variability of the coupled model, the model response exhibits a strong signature in sea surface temperature and precipitation over North America and the Sahel region. The existence and impacts of these ocean perturbations have important implications for decadal prediction: they can be seen either as a source of predictability or uncertainty, depending on whether the current observing system can detect them or not. In fact, comparing the magnitude of the imposed perturbations with the uncertainty of available ocean observations such as Argo data or ocean state estimates suggests that only the largest perturbations used in this study could be detectable. This highlights the importance for decadal climate prediction of accurate ocean density initialisation in the North Atlantic at intermediate and greater depths. Other/Unknown Material North Atlantic SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Climate Dynamics 51 5-6 2341 2357 |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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ftosti |
language |
unknown |
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54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Germe, Agathe Sévellec, Florian Mignot, Juliette Fedorov, Alexey Nguyen, Sébastien Swingedouw, Didier The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Decadal climate predictability in the North Atlantic is largely related to ocean low frequency variability, whose sensitivity to initial conditions is not very well understood. Recently, three-dimensional oceanic temperature anomalies optimally perturbing the North Atlantic Mean Temperature (NAMT) have been computed via an optimization procedure using a linear adjoint to a realistic ocean general circulation model. The spatial pattern of the identified perturbations, localized in the North Atlantic, has the largest magnitude between 1000 and 4000 m depth. In the present study, the impacts of these perturbations on NAMT, on the Atlantic meridional overturning circulation (AMOC), and on climate in general are investigated in a global coupled model that uses the same ocean model as was used to compute the three-dimensional optimal perturbations. In the coupled model, these perturbations induce AMOC and NAMT anomalies peaking after 5 and 10 years, respectively, generally consistent with the ocean-only linear predictions. To further understand their impact, their magnitude was varied in a broad range. For initial perturbations with a magnitude comparable to the internal variability of the coupled model, the model response exhibits a strong signature in sea surface temperature and precipitation over North America and the Sahel region. The existence and impacts of these ocean perturbations have important implications for decadal prediction: they can be seen either as a source of predictability or uncertainty, depending on whether the current observing system can detect them or not. In fact, comparing the magnitude of the imposed perturbations with the uncertainty of available ocean observations such as Argo data or ocean state estimates suggests that only the largest perturbations used in this study could be detectable. This highlights the importance for decadal climate prediction of accurate ocean density initialisation in the North Atlantic at intermediate and greater depths. |
author |
Germe, Agathe Sévellec, Florian Mignot, Juliette Fedorov, Alexey Nguyen, Sébastien Swingedouw, Didier |
author_facet |
Germe, Agathe Sévellec, Florian Mignot, Juliette Fedorov, Alexey Nguyen, Sébastien Swingedouw, Didier |
author_sort |
Germe, Agathe |
title |
The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability |
title_short |
The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability |
title_full |
The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability |
title_fullStr |
The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability |
title_full_unstemmed |
The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability |
title_sort |
impacts of oceanic deep temperature perturbations in the north atlantic on decadal climate variability and predictability |
publishDate |
2022 |
url |
http://www.osti.gov/servlets/purl/1507092 https://www.osti.gov/biblio/1507092 https://doi.org/10.1007/s00382-017-4016-z |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
http://www.osti.gov/servlets/purl/1507092 https://www.osti.gov/biblio/1507092 https://doi.org/10.1007/s00382-017-4016-z doi:10.1007/s00382-017-4016-z |
op_doi |
https://doi.org/10.1007/s00382-017-4016-z |
container_title |
Climate Dynamics |
container_volume |
51 |
container_issue |
5-6 |
container_start_page |
2341 |
op_container_end_page |
2357 |
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1772816982864822272 |