Water mass transformation variability in the Weddell Sea in ocean reanalyses
This study investigates the variability of water mass transformation (WMT) within the Weddell Gyre (WG). The WG serves as a pivotal site for the Meridional Overturning Circulation (MOC) and ocean ventilation because it is the primary origin of the largest volume of water mass in the global ocean: An...
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ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/pvqp-kp91 2023-07-23T04:14:34+02:00 Water mass transformation variability in the Weddell Sea in ocean reanalyses Bailey, Shanice T. Jones, C. Spencer Abernathey, Ryan Patrick Gordon, Arnold L. Yuan, Xiaojun 2023 https://doi.org/10.7916/pvqp-kp91 English eng https://doi.org/10.7916/pvqp-kp91 Physical oceanography Oceanography Water masses Bottom water (Oceanography) Thermodynamics Climatology Articles 2023 ftcolumbiauniv https://doi.org/10.7916/pvqp-kp91 2023-07-01T22:20:35Z This study investigates the variability of water mass transformation (WMT) within the Weddell Gyre (WG). The WG serves as a pivotal site for the Meridional Overturning Circulation (MOC) and ocean ventilation because it is the primary origin of the largest volume of water mass in the global ocean: Antarctic Bottom Water (AABW). Recent mooring data suggest substantial seasonal and interannual variability of AABW properties exiting the WG, and studies have linked the variability to the large-scale climate forcings affecting wind stress in the WG region. However, the specific thermodynamic mechanisms that link variability in surface forcings to variability in water mass transformations and AABW export remain unclear. This study explores how current state-of-the-art data-assimilating ocean reanalyses can help fill the gaps in our understanding of the thermodynamic drivers of AABW variability in the WG via WMT volume budgets derived from Walin's classic WMT framework. The three ocean reanalyses used are the following: Estimating the Circulation and Climate of the Ocean state estimate (ECCOv4), Southern Ocean State Estimate (SOSE) and Simple Ocean Data Assimilation (SODA). From the model outputs, we diagnose a closed form of the water mass budget for AABW that explicitly accounts for transport across the WG boundary, surface forcing, interior mixing and numerical mixing. We examine the annual mean climatology of the WMT budget terms, the seasonal climatology and finally the interannual variability. Our finding suggests that the relatively coarse resolution of these models did not realistically capture AABW formation, export and variability. In ECCO and SOSE, we see strong interannual variability in AABW volume budget. In SOSE, we find an accelerating loss of AABW during 2005–2010, driven largely by interior mixing and changes in surface salt fluxes. ECCO shows a similar trend during a 4-year time period starting in late 2007 but also reveals such trends to be part of interannual variability over a much longer time ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Weddell Sea Columbia University: Academic Commons Antarctic Southern Ocean Weddell Sea Weddell |
institution |
Open Polar |
collection |
Columbia University: Academic Commons |
op_collection_id |
ftcolumbiauniv |
language |
English |
topic |
Physical oceanography Oceanography Water masses Bottom water (Oceanography) Thermodynamics Climatology |
spellingShingle |
Physical oceanography Oceanography Water masses Bottom water (Oceanography) Thermodynamics Climatology Bailey, Shanice T. Jones, C. Spencer Abernathey, Ryan Patrick Gordon, Arnold L. Yuan, Xiaojun Water mass transformation variability in the Weddell Sea in ocean reanalyses |
topic_facet |
Physical oceanography Oceanography Water masses Bottom water (Oceanography) Thermodynamics Climatology |
description |
This study investigates the variability of water mass transformation (WMT) within the Weddell Gyre (WG). The WG serves as a pivotal site for the Meridional Overturning Circulation (MOC) and ocean ventilation because it is the primary origin of the largest volume of water mass in the global ocean: Antarctic Bottom Water (AABW). Recent mooring data suggest substantial seasonal and interannual variability of AABW properties exiting the WG, and studies have linked the variability to the large-scale climate forcings affecting wind stress in the WG region. However, the specific thermodynamic mechanisms that link variability in surface forcings to variability in water mass transformations and AABW export remain unclear. This study explores how current state-of-the-art data-assimilating ocean reanalyses can help fill the gaps in our understanding of the thermodynamic drivers of AABW variability in the WG via WMT volume budgets derived from Walin's classic WMT framework. The three ocean reanalyses used are the following: Estimating the Circulation and Climate of the Ocean state estimate (ECCOv4), Southern Ocean State Estimate (SOSE) and Simple Ocean Data Assimilation (SODA). From the model outputs, we diagnose a closed form of the water mass budget for AABW that explicitly accounts for transport across the WG boundary, surface forcing, interior mixing and numerical mixing. We examine the annual mean climatology of the WMT budget terms, the seasonal climatology and finally the interannual variability. Our finding suggests that the relatively coarse resolution of these models did not realistically capture AABW formation, export and variability. In ECCO and SOSE, we see strong interannual variability in AABW volume budget. In SOSE, we find an accelerating loss of AABW during 2005–2010, driven largely by interior mixing and changes in surface salt fluxes. ECCO shows a similar trend during a 4-year time period starting in late 2007 but also reveals such trends to be part of interannual variability over a much longer time ... |
format |
Article in Journal/Newspaper |
author |
Bailey, Shanice T. Jones, C. Spencer Abernathey, Ryan Patrick Gordon, Arnold L. Yuan, Xiaojun |
author_facet |
Bailey, Shanice T. Jones, C. Spencer Abernathey, Ryan Patrick Gordon, Arnold L. Yuan, Xiaojun |
author_sort |
Bailey, Shanice T. |
title |
Water mass transformation variability in the Weddell Sea in ocean reanalyses |
title_short |
Water mass transformation variability in the Weddell Sea in ocean reanalyses |
title_full |
Water mass transformation variability in the Weddell Sea in ocean reanalyses |
title_fullStr |
Water mass transformation variability in the Weddell Sea in ocean reanalyses |
title_full_unstemmed |
Water mass transformation variability in the Weddell Sea in ocean reanalyses |
title_sort |
water mass transformation variability in the weddell sea in ocean reanalyses |
publishDate |
2023 |
url |
https://doi.org/10.7916/pvqp-kp91 |
geographic |
Antarctic Southern Ocean Weddell Sea Weddell |
geographic_facet |
Antarctic Southern Ocean Weddell Sea Weddell |
genre |
Antarc* Antarctic Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Southern Ocean Weddell Sea |
op_relation |
https://doi.org/10.7916/pvqp-kp91 |
op_doi |
https://doi.org/10.7916/pvqp-kp91 |
_version_ |
1772185715884425216 |