Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen Basin
Abstract Antarctic Bottom Water has been warming in recent decades throughout most of the oceans and freshening in regions close to its Indian and Pacific sector sources. We assess warming rates on isobars in the eastern Pacific sector of the Southern Ocean using CTD data collected from shipboard su...
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| Format: | Article |
| Language: | English |
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Wiley
2024-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2024GL109937 |
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| author | Gregory C. Johnson A. K. M. Sadman Mahmud Alison M. Macdonald Benjamin S. Twining |
| author_facet | Gregory C. Johnson A. K. M. Sadman Mahmud Alison M. Macdonald Benjamin S. Twining |
| author_sort | Gregory C. Johnson |
| collection | DOAJ |
| description | Abstract Antarctic Bottom Water has been warming in recent decades throughout most of the oceans and freshening in regions close to its Indian and Pacific sector sources. We assess warming rates on isobars in the eastern Pacific sector of the Southern Ocean using CTD data collected from shipboard surveys from the early 1990s through the late 2010s together with CTD data collected from Deep Argo floats deployed in the region in January 2023. We show cooling and freshening in the temperature‐salinity relation for water colder than ∼0.4°C. We further find a recent acceleration in the regional bottom water warming rate vertically averaged for pressures exceeding 3,700 dbar, with the 2017/18 to 2023/24 trend of 7.5 (±0.9) m°C yr−1 nearly triple the 1992/95 to 2023/24 trend of 2.8 (±0.2) m°C yr−1. The 0.2°C isotherm descent rate for these same time periods nearly quadruples from 7.8 to 28 m yr−1. |
| format | Article |
| id | doaj-art-cf968357817848fe94debbfe0e9f725e |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2024-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-cf968357817848fe94debbfe0e9f725e2025-08-20T02:46:06ZengWileyGeophysical Research Letters0094-82761944-80072024-07-015113n/an/a10.1029/2024GL109937Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen BasinGregory C. Johnson0A. K. M. Sadman Mahmud1Alison M. Macdonald2Benjamin S. Twining3NOAA Pacific Marine Environmental Laboratory Seattle WA USABucknell University Lewisburg PA USAWoods Hole Oceanographic Institution Woods Hole MA USABigelow Laboratory for Ocean Sciences East Boothbay ME USAAbstract Antarctic Bottom Water has been warming in recent decades throughout most of the oceans and freshening in regions close to its Indian and Pacific sector sources. We assess warming rates on isobars in the eastern Pacific sector of the Southern Ocean using CTD data collected from shipboard surveys from the early 1990s through the late 2010s together with CTD data collected from Deep Argo floats deployed in the region in January 2023. We show cooling and freshening in the temperature‐salinity relation for water colder than ∼0.4°C. We further find a recent acceleration in the regional bottom water warming rate vertically averaged for pressures exceeding 3,700 dbar, with the 2017/18 to 2023/24 trend of 7.5 (±0.9) m°C yr−1 nearly triple the 1992/95 to 2023/24 trend of 2.8 (±0.2) m°C yr−1. The 0.2°C isotherm descent rate for these same time periods nearly quadruples from 7.8 to 28 m yr−1.https://doi.org/10.1029/2024GL109937Antarctic Bottom WaterDeep ArgoBellingshausen Basin |
| spellingShingle | Gregory C. Johnson A. K. M. Sadman Mahmud Alison M. Macdonald Benjamin S. Twining Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen Basin Geophysical Research Letters Antarctic Bottom Water Deep Argo Bellingshausen Basin |
| title | Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen Basin |
| title_full | Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen Basin |
| title_fullStr | Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen Basin |
| title_full_unstemmed | Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen Basin |
| title_short | Antarctic Bottom Water Warming, Freshening, and Contraction in the Eastern Bellingshausen Basin |
| title_sort | antarctic bottom water warming freshening and contraction in the eastern bellingshausen basin |
| topic | Antarctic Bottom Water Deep Argo Bellingshausen Basin |
| url | https://doi.org/10.1029/2024GL109937 |
| work_keys_str_mv | AT gregorycjohnson antarcticbottomwaterwarmingfresheningandcontractionintheeasternbellingshausenbasin AT akmsadmanmahmud antarcticbottomwaterwarmingfresheningandcontractionintheeasternbellingshausenbasin AT alisonmmacdonald antarcticbottomwaterwarmingfresheningandcontractionintheeasternbellingshausenbasin AT benjaminstwining antarcticbottomwaterwarmingfresheningandcontractionintheeasternbellingshausenbasin |