Surface factors controlling the volume of accumulated Labrador Sea Water
Abstract. We explore historical variability in the volume of Labrador Sea Water (LSW) using ECCO, an ocean state estimate configuration of the Massachusetts Institute of Technology general circulation model (MITgcm). The model’s adjoint, a linearization of the MITgcm, is set up to output the lagged...
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ftinsu:oai:HAL:hal-04299663v1 2024-04-14T08:13:53+00:00 Surface factors controlling the volume of accumulated Labrador Sea Water Kostov, Yavor Messias, Marie-José Mercier, Herlé Marshall, David Johnson, Helen University of Exeter Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) University of Oxford school of mathematical sciences Queensland University of Technology Brisbane (QUT) 2023-11-22 https://hal.science/hal-04299663 https://doi.org/10.5194/egusphere-2023-1564 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-2023-1564 hal-04299663 https://hal.science/hal-04299663 doi:10.5194/egusphere-2023-1564 https://hal.science/hal-04299663 2023 [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/preprint Preprints, Working Papers, . 2023 ftinsu https://doi.org/10.5194/egusphere-2023-1564 2024-03-21T17:04:55Z Abstract. We explore historical variability in the volume of Labrador Sea Water (LSW) using ECCO, an ocean state estimate configuration of the Massachusetts Institute of Technology general circulation model (MITgcm). The model’s adjoint, a linearization of the MITgcm, is set up to output the lagged sensitivity of the watermass volume to surface boundary conditions. This allows us to reconstruct the evolution of LSW volume over recent decades using historical surface wind stress, heat, and freshwater fluxes. Each of these boundary conditions contributes significantly to the LSW variability that we recover, but these impacts are associated with different geographical fingerprints and arise over a range of time lags. We show that the volume of LSW accumulated in the Labrador Sea exhibits a delayed response to surface wind stress and buoyancy forcing outside the convective interior of the Labrador Sea, at key locations in the North Atlantic Ocean. In particular, winds and surface density anomalies affect the North Atlantic Current’s (NAC) transport of warm and saline subtropical water masses that are precursors for the formation of LSW. This propensity for a delayed response of LSW to remote forcing allows us to predict a substantial fraction of LSW variability at least a year into the future. Our analysis also enables us to attribute LSW variability to different boundary conditions and to gain insight into the major mechanisms that drive volume anomalies in this deep watermass. We point out the important role of buoyancy loss and preconditioning along the NAC pathway, in the Iceland Basin, the Irminger Sea, and the Nordic Seas, processes which facilitate the formation of LSW both in the Irminger and in the Labrador Sea. Report Iceland Labrador Sea Nordic Seas North Atlantic Institut national des sciences de l'Univers: HAL-INSU Irminger Sea ENVELOPE(-34.041,-34.041,63.054,63.054) |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDU]Sciences of the Universe [physics] |
spellingShingle |
[SDU]Sciences of the Universe [physics] Kostov, Yavor Messias, Marie-José Mercier, Herlé Marshall, David Johnson, Helen Surface factors controlling the volume of accumulated Labrador Sea Water |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
Abstract. We explore historical variability in the volume of Labrador Sea Water (LSW) using ECCO, an ocean state estimate configuration of the Massachusetts Institute of Technology general circulation model (MITgcm). The model’s adjoint, a linearization of the MITgcm, is set up to output the lagged sensitivity of the watermass volume to surface boundary conditions. This allows us to reconstruct the evolution of LSW volume over recent decades using historical surface wind stress, heat, and freshwater fluxes. Each of these boundary conditions contributes significantly to the LSW variability that we recover, but these impacts are associated with different geographical fingerprints and arise over a range of time lags. We show that the volume of LSW accumulated in the Labrador Sea exhibits a delayed response to surface wind stress and buoyancy forcing outside the convective interior of the Labrador Sea, at key locations in the North Atlantic Ocean. In particular, winds and surface density anomalies affect the North Atlantic Current’s (NAC) transport of warm and saline subtropical water masses that are precursors for the formation of LSW. This propensity for a delayed response of LSW to remote forcing allows us to predict a substantial fraction of LSW variability at least a year into the future. Our analysis also enables us to attribute LSW variability to different boundary conditions and to gain insight into the major mechanisms that drive volume anomalies in this deep watermass. We point out the important role of buoyancy loss and preconditioning along the NAC pathway, in the Iceland Basin, the Irminger Sea, and the Nordic Seas, processes which facilitate the formation of LSW both in the Irminger and in the Labrador Sea. |
author2 |
University of Exeter Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) University of Oxford school of mathematical sciences Queensland University of Technology Brisbane (QUT) |
format |
Report |
author |
Kostov, Yavor Messias, Marie-José Mercier, Herlé Marshall, David Johnson, Helen |
author_facet |
Kostov, Yavor Messias, Marie-José Mercier, Herlé Marshall, David Johnson, Helen |
author_sort |
Kostov, Yavor |
title |
Surface factors controlling the volume of accumulated Labrador Sea Water |
title_short |
Surface factors controlling the volume of accumulated Labrador Sea Water |
title_full |
Surface factors controlling the volume of accumulated Labrador Sea Water |
title_fullStr |
Surface factors controlling the volume of accumulated Labrador Sea Water |
title_full_unstemmed |
Surface factors controlling the volume of accumulated Labrador Sea Water |
title_sort |
surface factors controlling the volume of accumulated labrador sea water |
publisher |
HAL CCSD |
publishDate |
2023 |
url |
https://hal.science/hal-04299663 https://doi.org/10.5194/egusphere-2023-1564 |
long_lat |
ENVELOPE(-34.041,-34.041,63.054,63.054) |
geographic |
Irminger Sea |
geographic_facet |
Irminger Sea |
genre |
Iceland Labrador Sea Nordic Seas North Atlantic |
genre_facet |
Iceland Labrador Sea Nordic Seas North Atlantic |
op_source |
https://hal.science/hal-04299663 2023 |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-2023-1564 hal-04299663 https://hal.science/hal-04299663 doi:10.5194/egusphere-2023-1564 |
op_doi |
https://doi.org/10.5194/egusphere-2023-1564 |
_version_ |
1796311962249854976 |