Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica
Around most of Antarctica, the Circumpolar Deep Water (CDW) shows a warming trend. At the same time, the thermocline is shoaling, thereby increasing the potential for CDW to enter the shallow continental shelves and ultimately increase basal melt in the ice shelf cavities that line the coast. Simila...
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2023
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ftdoajarticles:oai:doaj.org/article:b8dee91837494f53a92f2391b32df212 2023-06-11T04:05:58+02:00 Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica E. Darelius V. Dundas M. Janout S. Tippenhauer 2023-05-01T00:00:00Z https://doi.org/10.5194/os-19-671-2023 https://doaj.org/article/b8dee91837494f53a92f2391b32df212 EN eng Copernicus Publications https://os.copernicus.org/articles/19/671/2023/os-19-671-2023.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-19-671-2023 1812-0784 1812-0792 https://doaj.org/article/b8dee91837494f53a92f2391b32df212 Ocean Science, Vol 19, Pp 671-683 (2023) Geography. Anthropology. Recreation G Environmental sciences GE1-350 article 2023 ftdoajarticles https://doi.org/10.5194/os-19-671-2023 2023-05-28T00:37:25Z Around most of Antarctica, the Circumpolar Deep Water (CDW) shows a warming trend. At the same time, the thermocline is shoaling, thereby increasing the potential for CDW to enter the shallow continental shelves and ultimately increase basal melt in the ice shelf cavities that line the coast. Similar trends, on the order of 0.05 ∘ C and 3 m per decade, have been observed in the Warm Deep Water (WDW), the slightly cooled CDW derivative found at depth in the Weddell Sea. Here, we report on a sudden, local increase in the temperature maximum of the WDW above the continental slope north of the Filchner Trough (74 ∘ S, 25–40 ∘ W), a region identified as a hotspot for both Antarctic Bottom Water formation (AABW) and potential changes in the flow of WDW towards the large Filchner–Ronne Ice Shelf. New conductivity–temperature–depth profiles, obtained in summer 2021, and recent (2017–2021) mooring records show that the temperature of the warm-water core increased by about 0.1 ∘ C over the upper part of the slope (700–2750 m depth) compared with historical (1973–2018) measurements. The temperature increase occurred relatively suddenly in late 2019 and was accompanied by an unprecedented (in observations) freshening of the overlying winter water. The AABW descending down the continental slope from Filchner Trough is sourced by dense ice shelf water and consists to a large degree (60 %) of entrained WDW. The observed temperature increase can hence be expected to imprint directly on deep-water properties, increasing the temperature of newly produced bottom water (by up to 0.06 ∘ C) and reducing its density. Article in Journal/Newspaper Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ronne Ice Shelf Weddell Sea Directory of Open Access Journals: DOAJ Articles Antarctic Filchner Trough ENVELOPE(-36.000,-36.000,-77.000,-77.000) Ronne Ice Shelf ENVELOPE(-61.000,-61.000,-78.500,-78.500) Weddell Weddell Sea Ocean Science 19 3 671 683 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
spellingShingle |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 E. Darelius V. Dundas M. Janout S. Tippenhauer Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica |
topic_facet |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
description |
Around most of Antarctica, the Circumpolar Deep Water (CDW) shows a warming trend. At the same time, the thermocline is shoaling, thereby increasing the potential for CDW to enter the shallow continental shelves and ultimately increase basal melt in the ice shelf cavities that line the coast. Similar trends, on the order of 0.05 ∘ C and 3 m per decade, have been observed in the Warm Deep Water (WDW), the slightly cooled CDW derivative found at depth in the Weddell Sea. Here, we report on a sudden, local increase in the temperature maximum of the WDW above the continental slope north of the Filchner Trough (74 ∘ S, 25–40 ∘ W), a region identified as a hotspot for both Antarctic Bottom Water formation (AABW) and potential changes in the flow of WDW towards the large Filchner–Ronne Ice Shelf. New conductivity–temperature–depth profiles, obtained in summer 2021, and recent (2017–2021) mooring records show that the temperature of the warm-water core increased by about 0.1 ∘ C over the upper part of the slope (700–2750 m depth) compared with historical (1973–2018) measurements. The temperature increase occurred relatively suddenly in late 2019 and was accompanied by an unprecedented (in observations) freshening of the overlying winter water. The AABW descending down the continental slope from Filchner Trough is sourced by dense ice shelf water and consists to a large degree (60 %) of entrained WDW. The observed temperature increase can hence be expected to imprint directly on deep-water properties, increasing the temperature of newly produced bottom water (by up to 0.06 ∘ C) and reducing its density. |
format |
Article in Journal/Newspaper |
author |
E. Darelius V. Dundas M. Janout S. Tippenhauer |
author_facet |
E. Darelius V. Dundas M. Janout S. Tippenhauer |
author_sort |
E. Darelius |
title |
Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica |
title_short |
Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica |
title_full |
Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica |
title_fullStr |
Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica |
title_full_unstemmed |
Sudden, local temperature increase above the continental slope in the southern Weddell Sea, Antarctica |
title_sort |
sudden, local temperature increase above the continental slope in the southern weddell sea, antarctica |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/os-19-671-2023 https://doaj.org/article/b8dee91837494f53a92f2391b32df212 |
long_lat |
ENVELOPE(-36.000,-36.000,-77.000,-77.000) ENVELOPE(-61.000,-61.000,-78.500,-78.500) |
geographic |
Antarctic Filchner Trough Ronne Ice Shelf Weddell Weddell Sea |
geographic_facet |
Antarctic Filchner Trough Ronne Ice Shelf Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ronne Ice Shelf Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ronne Ice Shelf Weddell Sea |
op_source |
Ocean Science, Vol 19, Pp 671-683 (2023) |
op_relation |
https://os.copernicus.org/articles/19/671/2023/os-19-671-2023.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 doi:10.5194/os-19-671-2023 1812-0784 1812-0792 https://doaj.org/article/b8dee91837494f53a92f2391b32df212 |
op_doi |
https://doi.org/10.5194/os-19-671-2023 |
container_title |
Ocean Science |
container_volume |
19 |
container_issue |
3 |
container_start_page |
671 |
op_container_end_page |
683 |
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1768377678770995200 |