Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications
Abstract This paper describes the development of New Zealand's Earth System Model (NZESM) and evaluates its performance against its parent model (United Kingdom Earth System Model, UKESM) and observations. The main difference between the two earth system models is an embedded high‐resolution (1...
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ftdoajarticles:oai:doaj.org/article:9c705ab3bd144f7782b5ee961ff46543 2023-05-15T13:42:02+02:00 Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications Erik Behrens Jonny Williams Olaf Morgenstern Phil Sutton Graham Rickard Michael J. M. Williams 2020-07-01T00:00:00Z https://doi.org/10.1029/2019MS001996 https://doaj.org/article/9c705ab3bd144f7782b5ee961ff46543 EN eng American Geophysical Union (AGU) https://doi.org/10.1029/2019MS001996 https://doaj.org/toc/1942-2466 1942-2466 doi:10.1029/2019MS001996 https://doaj.org/article/9c705ab3bd144f7782b5ee961ff46543 Journal of Advances in Modeling Earth Systems, Vol 12, Iss 7, Pp n/a-n/a (2020) Earth system model AGRIF Tasman Sea refined ocean grid model bias super‐gyre Physical geography GB3-5030 Oceanography GC1-1581 article 2020 ftdoajarticles https://doi.org/10.1029/2019MS001996 2022-12-31T13:17:04Z Abstract This paper describes the development of New Zealand's Earth System Model (NZESM) and evaluates its performance against its parent model (United Kingdom Earth System Model, UKESM) and observations. The main difference between the two earth system models is an embedded high‐resolution (1/5°) nested region over the oceans around New Zealand in the NZESM. Due to this finer ocean model mesh, currents such as the East Australian Current, East Australian Current Extension, Tasman Front, and Tasman Leakage, and their volume and heat transports are better simulated in the NZESM. The improved oceanic transports have led to a reduction in upper ocean temperature and salinity biases over the nested region. In addition, net transports through the Tasman Sea of volume, heat and salt in the NZESM agree better with previously reported estimates. A consequence of the increased cross‐Tasman Sea transports in the NZESM is increased temperatures and salinity west of Australia and in the Southern Ocean reducing the meridional sea surface temperature gradient between the subtropics and sub‐Antarctic. This also leads to a weakening of the westerly winds between 60°S and 45°S over large parts of the Southern Ocean, which reduces the northward Ekman transport, reduces the formation of Antarctic Intermediate Water, and allows for a southward expansion of the Super‐Gyre in all ocean basins. Connecting an improved oceanic circulation around New Zealand to a basin‐wide Super‐Gyre response is an important step forward in our current understanding of how local scales can influence global scales in a fully coupled earth system model. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Directory of Open Access Journals: DOAJ Articles Antarctic New Zealand Southern Ocean Journal of Advances in Modeling Earth Systems 12 7 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Earth system model AGRIF Tasman Sea refined ocean grid model bias super‐gyre Physical geography GB3-5030 Oceanography GC1-1581 |
spellingShingle |
Earth system model AGRIF Tasman Sea refined ocean grid model bias super‐gyre Physical geography GB3-5030 Oceanography GC1-1581 Erik Behrens Jonny Williams Olaf Morgenstern Phil Sutton Graham Rickard Michael J. M. Williams Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications |
topic_facet |
Earth system model AGRIF Tasman Sea refined ocean grid model bias super‐gyre Physical geography GB3-5030 Oceanography GC1-1581 |
description |
Abstract This paper describes the development of New Zealand's Earth System Model (NZESM) and evaluates its performance against its parent model (United Kingdom Earth System Model, UKESM) and observations. The main difference between the two earth system models is an embedded high‐resolution (1/5°) nested region over the oceans around New Zealand in the NZESM. Due to this finer ocean model mesh, currents such as the East Australian Current, East Australian Current Extension, Tasman Front, and Tasman Leakage, and their volume and heat transports are better simulated in the NZESM. The improved oceanic transports have led to a reduction in upper ocean temperature and salinity biases over the nested region. In addition, net transports through the Tasman Sea of volume, heat and salt in the NZESM agree better with previously reported estimates. A consequence of the increased cross‐Tasman Sea transports in the NZESM is increased temperatures and salinity west of Australia and in the Southern Ocean reducing the meridional sea surface temperature gradient between the subtropics and sub‐Antarctic. This also leads to a weakening of the westerly winds between 60°S and 45°S over large parts of the Southern Ocean, which reduces the northward Ekman transport, reduces the formation of Antarctic Intermediate Water, and allows for a southward expansion of the Super‐Gyre in all ocean basins. Connecting an improved oceanic circulation around New Zealand to a basin‐wide Super‐Gyre response is an important step forward in our current understanding of how local scales can influence global scales in a fully coupled earth system model. |
format |
Article in Journal/Newspaper |
author |
Erik Behrens Jonny Williams Olaf Morgenstern Phil Sutton Graham Rickard Michael J. M. Williams |
author_facet |
Erik Behrens Jonny Williams Olaf Morgenstern Phil Sutton Graham Rickard Michael J. M. Williams |
author_sort |
Erik Behrens |
title |
Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications |
title_short |
Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications |
title_full |
Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications |
title_fullStr |
Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications |
title_full_unstemmed |
Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super‐Gyre Circulation Implications |
title_sort |
local grid refinement in new zealand's earth system model: tasman sea ocean circulation improvements and super‐gyre circulation implications |
publisher |
American Geophysical Union (AGU) |
publishDate |
2020 |
url |
https://doi.org/10.1029/2019MS001996 https://doaj.org/article/9c705ab3bd144f7782b5ee961ff46543 |
geographic |
Antarctic New Zealand Southern Ocean |
geographic_facet |
Antarctic New Zealand Southern Ocean |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Journal of Advances in Modeling Earth Systems, Vol 12, Iss 7, Pp n/a-n/a (2020) |
op_relation |
https://doi.org/10.1029/2019MS001996 https://doaj.org/toc/1942-2466 1942-2466 doi:10.1029/2019MS001996 https://doaj.org/article/9c705ab3bd144f7782b5ee961ff46543 |
op_doi |
https://doi.org/10.1029/2019MS001996 |
container_title |
Journal of Advances in Modeling Earth Systems |
container_volume |
12 |
container_issue |
7 |
_version_ |
1766161905425055744 |