The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017
Abstract A description and assessment of the first release of the Arctic Subpolar gyre sTate Estimate (ASTE_R1), a data‐constrained ocean‐sea ice model‐data synthesis, is presented. ASTE_R1 has a nominal resolution of 1/3° and spans the period 2002–2017. The fit of the model to an extensive (O(109))...
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American Geophysical Union (AGU)
2021
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ftdoajarticles:oai:doaj.org/article:cf315ab640e04d349320c72cda7f5931 2023-05-15T14:38:45+02:00 The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017 An T. Nguyen Helen Pillar Victor Ocaña Arash Bigdeli Timothy A. Smith Patrick Heimbach 2021-05-01T00:00:00Z https://doi.org/10.1029/2020MS002398 https://doaj.org/article/cf315ab640e04d349320c72cda7f5931 EN eng American Geophysical Union (AGU) https://doi.org/10.1029/2020MS002398 https://doaj.org/toc/1942-2466 1942-2466 doi:10.1029/2020MS002398 https://doaj.org/article/cf315ab640e04d349320c72cda7f5931 Journal of Advances in Modeling Earth Systems, Vol 13, Iss 5, Pp n/a-n/a (2021) Arctic Mediterranean data assimilation heat and freshwater exchange ocean‐sea ice state estimate subpolar north Atlantic Physical geography GB3-5030 Oceanography GC1-1581 article 2021 ftdoajarticles https://doi.org/10.1029/2020MS002398 2022-12-31T09:07:45Z Abstract A description and assessment of the first release of the Arctic Subpolar gyre sTate Estimate (ASTE_R1), a data‐constrained ocean‐sea ice model‐data synthesis, is presented. ASTE_R1 has a nominal resolution of 1/3° and spans the period 2002–2017. The fit of the model to an extensive (O(109)) set of satellite and in situ observations was achieved through adjoint‐based nonlinear least squares optimization. The improvement of the solution compared to an unconstrained simulation is reflected in misfit reductions of 77% for Argo, 50% for satellite sea surface height, 58% for the Fram Strait mooring, 65% for Ice Tethered Profilers, and 83% for sea ice extent. Exact dynamical and kinematic consistency is a key advantage of ASTE_R1, distinguishing the state estimate from existing ocean reanalyses. Through strict adherence to conservation laws, all sources and sinks within ASTE_R1 can be accounted for, permitting meaningful analysis of closed budgets at the grid‐scale, such as contributions of horizontal and vertical convergence to the tendencies of heat and salt. ASTE_R1 thus serves as the biggest effort undertaken to date of producing a specialized Arctic ocean‐ice estimate over the 21st century. Transports of volume, heat, and freshwater are consistent with published observation‐based estimates across important Arctic Mediterranean gateways. Interannual variability and low frequency trends of freshwater and heat content are well represented in the Barents Sea, western Arctic halocline, and east subpolar North Atlantic. Systematic biases remain in ASTE_R1, including a warm bias in the Atlantic Water layer in the Arctic and deficient freshwater inputs from rivers and Greenland discharge. Article in Journal/Newspaper Arctic Arctic Ocean Barents Sea Fram Strait Greenland North Atlantic Sea ice Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Barents Sea Greenland Journal of Advances in Modeling Earth Systems 13 5 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Arctic Mediterranean data assimilation heat and freshwater exchange ocean‐sea ice state estimate subpolar north Atlantic Physical geography GB3-5030 Oceanography GC1-1581 |
spellingShingle |
Arctic Mediterranean data assimilation heat and freshwater exchange ocean‐sea ice state estimate subpolar north Atlantic Physical geography GB3-5030 Oceanography GC1-1581 An T. Nguyen Helen Pillar Victor Ocaña Arash Bigdeli Timothy A. Smith Patrick Heimbach The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017 |
topic_facet |
Arctic Mediterranean data assimilation heat and freshwater exchange ocean‐sea ice state estimate subpolar north Atlantic Physical geography GB3-5030 Oceanography GC1-1581 |
description |
Abstract A description and assessment of the first release of the Arctic Subpolar gyre sTate Estimate (ASTE_R1), a data‐constrained ocean‐sea ice model‐data synthesis, is presented. ASTE_R1 has a nominal resolution of 1/3° and spans the period 2002–2017. The fit of the model to an extensive (O(109)) set of satellite and in situ observations was achieved through adjoint‐based nonlinear least squares optimization. The improvement of the solution compared to an unconstrained simulation is reflected in misfit reductions of 77% for Argo, 50% for satellite sea surface height, 58% for the Fram Strait mooring, 65% for Ice Tethered Profilers, and 83% for sea ice extent. Exact dynamical and kinematic consistency is a key advantage of ASTE_R1, distinguishing the state estimate from existing ocean reanalyses. Through strict adherence to conservation laws, all sources and sinks within ASTE_R1 can be accounted for, permitting meaningful analysis of closed budgets at the grid‐scale, such as contributions of horizontal and vertical convergence to the tendencies of heat and salt. ASTE_R1 thus serves as the biggest effort undertaken to date of producing a specialized Arctic ocean‐ice estimate over the 21st century. Transports of volume, heat, and freshwater are consistent with published observation‐based estimates across important Arctic Mediterranean gateways. Interannual variability and low frequency trends of freshwater and heat content are well represented in the Barents Sea, western Arctic halocline, and east subpolar North Atlantic. Systematic biases remain in ASTE_R1, including a warm bias in the Atlantic Water layer in the Arctic and deficient freshwater inputs from rivers and Greenland discharge. |
format |
Article in Journal/Newspaper |
author |
An T. Nguyen Helen Pillar Victor Ocaña Arash Bigdeli Timothy A. Smith Patrick Heimbach |
author_facet |
An T. Nguyen Helen Pillar Victor Ocaña Arash Bigdeli Timothy A. Smith Patrick Heimbach |
author_sort |
An T. Nguyen |
title |
The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017 |
title_short |
The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017 |
title_full |
The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017 |
title_fullStr |
The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017 |
title_full_unstemmed |
The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017 |
title_sort |
arctic subpolar gyre state estimate: description and assessment of a data‐constrained, dynamically consistent ocean‐sea ice estimate for 2002–2017 |
publisher |
American Geophysical Union (AGU) |
publishDate |
2021 |
url |
https://doi.org/10.1029/2020MS002398 https://doaj.org/article/cf315ab640e04d349320c72cda7f5931 |
geographic |
Arctic Arctic Ocean Barents Sea Greenland |
geographic_facet |
Arctic Arctic Ocean Barents Sea Greenland |
genre |
Arctic Arctic Ocean Barents Sea Fram Strait Greenland North Atlantic Sea ice |
genre_facet |
Arctic Arctic Ocean Barents Sea Fram Strait Greenland North Atlantic Sea ice |
op_source |
Journal of Advances in Modeling Earth Systems, Vol 13, Iss 5, Pp n/a-n/a (2021) |
op_relation |
https://doi.org/10.1029/2020MS002398 https://doaj.org/toc/1942-2466 1942-2466 doi:10.1029/2020MS002398 https://doaj.org/article/cf315ab640e04d349320c72cda7f5931 |
op_doi |
https://doi.org/10.1029/2020MS002398 |
container_title |
Journal of Advances in Modeling Earth Systems |
container_volume |
13 |
container_issue |
5 |
_version_ |
1766310775684595712 |