Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height
The Southern Ocean plays a central role in regulating the global overturing circulation, ventilating the deep ocean, and driving sea level rise by delivering heat to Antarctic ice shelves. Understanding heat and freshwater content in this region is key to monitoring these global processes and identi...
Main Authors: | , , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus GmbH
2023
|
Subjects: | |
Online Access: | https://archimer.ifremer.fr/doc/00869/98134/107435.pdf https://archimer.ifremer.fr/doc/00869/98134/107436.pdf https://doi.org/10.5194/egusphere-2023-3050 https://archimer.ifremer.fr/doc/00869/98134/ |
id |
ftarchimer:oai:archimer.ifremer.fr:98134 |
---|---|
record_format |
openpolar |
spelling |
ftarchimer:oai:archimer.ifremer.fr:98134 2024-02-04T09:53:46+01:00 Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height Cocks, Jennifer Silvano, Alessandro Marzocchi, Alice Dragomir, Oana Schifano, Noemie Hogg, Anna E. Naveira Garabato, Alberto C. 2023-12-22 application/pdf https://archimer.ifremer.fr/doc/00869/98134/107435.pdf https://archimer.ifremer.fr/doc/00869/98134/107436.pdf https://doi.org/10.5194/egusphere-2023-3050 https://archimer.ifremer.fr/doc/00869/98134/ eng eng Copernicus GmbH https://archimer.ifremer.fr/doc/00869/98134/107435.pdf https://archimer.ifremer.fr/doc/00869/98134/107436.pdf doi:10.5194/egusphere-2023-3050 https://archimer.ifremer.fr/doc/00869/98134/ info:eu-repo/semantics/openAccess restricted use EGUsphere (Copernicus GmbH) In Press text Article info:eu-repo/semantics/article 2023 ftarchimer https://doi.org/10.5194/egusphere-2023-3050 2024-01-09T23:51:11Z The Southern Ocean plays a central role in regulating the global overturing circulation, ventilating the deep ocean, and driving sea level rise by delivering heat to Antarctic ice shelves. Understanding heat and freshwater content in this region is key to monitoring these global processes and identifying multiyear changes; however, in-situ observations are limited, and often do not offer the spatial or temporal consistency needed to study long-term variability. Perturbations in steric height can reveal changes in oceanic heat and freshwater content inasmuch as they impact the density of the water column. Here, we show for the first time that the monthly steric height anomaly of the Southern Ocean south of 50° S can be assessed using altimetry and GRACE gravimetry data from 2002 to 2018. Steric height anomalies are validated against in-situ Argo float and CTD data from tagged elephant seals. We find good agreement in the ice-free ocean and parts of the seasonal ice zone, but that the uncertainty of steric height increases on the Antarctic continental shelf and within the permanent ice zone due to leakage error and anti-aliasing in GRACE. The open-ocean steric height anomalies exhibit spatio-temporally coherent patterns that: (i) capture the expected seasonal cycle of low (high) steric height in winter (summer); and (ii) reflect interannual anomalies in surface heat and freshwater content and wind forcing associated with positive and negative phases of the two major modes of Southern Hemisphere climate variability (the El Niño – Southern Oscillation and Southern Annular Mode). Article in Journal/Newspaper Antarc* Antarctic Elephant Seals Ice Shelves Southern Ocean Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Antarctic Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
The Southern Ocean plays a central role in regulating the global overturing circulation, ventilating the deep ocean, and driving sea level rise by delivering heat to Antarctic ice shelves. Understanding heat and freshwater content in this region is key to monitoring these global processes and identifying multiyear changes; however, in-situ observations are limited, and often do not offer the spatial or temporal consistency needed to study long-term variability. Perturbations in steric height can reveal changes in oceanic heat and freshwater content inasmuch as they impact the density of the water column. Here, we show for the first time that the monthly steric height anomaly of the Southern Ocean south of 50° S can be assessed using altimetry and GRACE gravimetry data from 2002 to 2018. Steric height anomalies are validated against in-situ Argo float and CTD data from tagged elephant seals. We find good agreement in the ice-free ocean and parts of the seasonal ice zone, but that the uncertainty of steric height increases on the Antarctic continental shelf and within the permanent ice zone due to leakage error and anti-aliasing in GRACE. The open-ocean steric height anomalies exhibit spatio-temporally coherent patterns that: (i) capture the expected seasonal cycle of low (high) steric height in winter (summer); and (ii) reflect interannual anomalies in surface heat and freshwater content and wind forcing associated with positive and negative phases of the two major modes of Southern Hemisphere climate variability (the El Niño – Southern Oscillation and Southern Annular Mode). |
format |
Article in Journal/Newspaper |
author |
Cocks, Jennifer Silvano, Alessandro Marzocchi, Alice Dragomir, Oana Schifano, Noemie Hogg, Anna E. Naveira Garabato, Alberto C. |
spellingShingle |
Cocks, Jennifer Silvano, Alessandro Marzocchi, Alice Dragomir, Oana Schifano, Noemie Hogg, Anna E. Naveira Garabato, Alberto C. Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height |
author_facet |
Cocks, Jennifer Silvano, Alessandro Marzocchi, Alice Dragomir, Oana Schifano, Noemie Hogg, Anna E. Naveira Garabato, Alberto C. |
author_sort |
Cocks, Jennifer |
title |
Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height |
title_short |
Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height |
title_full |
Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height |
title_fullStr |
Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height |
title_full_unstemmed |
Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height |
title_sort |
assessing heat and freshwater changes in the southern ocean using satellite-derived steric height |
publisher |
Copernicus GmbH |
publishDate |
2023 |
url |
https://archimer.ifremer.fr/doc/00869/98134/107435.pdf https://archimer.ifremer.fr/doc/00869/98134/107436.pdf https://doi.org/10.5194/egusphere-2023-3050 https://archimer.ifremer.fr/doc/00869/98134/ |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Elephant Seals Ice Shelves Southern Ocean |
genre_facet |
Antarc* Antarctic Elephant Seals Ice Shelves Southern Ocean |
op_source |
EGUsphere (Copernicus GmbH) In Press |
op_relation |
https://archimer.ifremer.fr/doc/00869/98134/107435.pdf https://archimer.ifremer.fr/doc/00869/98134/107436.pdf doi:10.5194/egusphere-2023-3050 https://archimer.ifremer.fr/doc/00869/98134/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.5194/egusphere-2023-3050 |
_version_ |
1789968047143911424 |