{"title":"由离岸传播的密水涡驱动的南极海槽中的跨大陆架交换","authors":"Alan Gaul, W. Zhang, C. Cenedese","doi":"10.1175/jpo-d-23-0088.1","DOIUrl":null,"url":null,"abstract":"\nThis study examines the link between near-bottom outflows of dense water formed in Antarctic coastal polynyas and onshore intrusions of Circumpolar Deep Water (CDW) through prograde troughs cutting across the continental shelf. Numerical simulations show that the dense water outflow is primarily in the form of cyclonic eddies. The trough serves as a topographic guide that organizes the offshore-moving dense water eddies into a chain pattern. The offshore migration speed of the dense water eddies is similar to the velocity of the dense water offshore flow in the trough, which scaling analysis finds to be proportional to the reduced gravity of the dense water and the slope of the trough side walls and to be inversely proportional to the Coriolis parameter. Our model simulations indicate that, as these cyclonic dense water eddies move across the trough mouth into the deep ocean, they entrain CDW from offshore and carry CDW clockwise along their periphery into the trough. Subsequent cyclonic dense water eddies then entrain the intruding CDW further toward the coast along the trough. This process of recurring onshore entrainment of CDW by a topographically constrained chain of offshore-flowing dense water eddies is consistent with topographic hotspots of onshore intrusion of CDW around Antarctica identified by other studies. It can bring CDW from offshore to close to the coast and thus impact the heat flux into Antarctic coastal regions, affecting interactions among ocean, sea ice, and ice shelves.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Cross-Shelf Exchange in Prograde Antarctic Troughs Driven by Offshore Propagating Dense Water Eddies\",\"authors\":\"Alan Gaul, W. Zhang, C. Cenedese\",\"doi\":\"10.1175/jpo-d-23-0088.1\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"\\nThis study examines the link between near-bottom outflows of dense water formed in Antarctic coastal polynyas and onshore intrusions of Circumpolar Deep Water (CDW) through prograde troughs cutting across the continental shelf. Numerical simulations show that the dense water outflow is primarily in the form of cyclonic eddies. The trough serves as a topographic guide that organizes the offshore-moving dense water eddies into a chain pattern. The offshore migration speed of the dense water eddies is similar to the velocity of the dense water offshore flow in the trough, which scaling analysis finds to be proportional to the reduced gravity of the dense water and the slope of the trough side walls and to be inversely proportional to the Coriolis parameter. Our model simulations indicate that, as these cyclonic dense water eddies move across the trough mouth into the deep ocean, they entrain CDW from offshore and carry CDW clockwise along their periphery into the trough. Subsequent cyclonic dense water eddies then entrain the intruding CDW further toward the coast along the trough. This process of recurring onshore entrainment of CDW by a topographically constrained chain of offshore-flowing dense water eddies is consistent with topographic hotspots of onshore intrusion of CDW around Antarctica identified by other studies. It can bring CDW from offshore to close to the coast and thus impact the heat flux into Antarctic coastal regions, affecting interactions among ocean, sea ice, and ice shelves.\",\"PeriodicalId\":56115,\"journal\":{\"name\":\"Journal of Physical Oceanography\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.8000,\"publicationDate\":\"2024-04-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Physical Oceanography\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1175/jpo-d-23-0088.1\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"OCEANOGRAPHY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Physical Oceanography","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1175/jpo-d-23-0088.1","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"OCEANOGRAPHY","Score":null,"Total":0}
Cross-Shelf Exchange in Prograde Antarctic Troughs Driven by Offshore Propagating Dense Water Eddies
This study examines the link between near-bottom outflows of dense water formed in Antarctic coastal polynyas and onshore intrusions of Circumpolar Deep Water (CDW) through prograde troughs cutting across the continental shelf. Numerical simulations show that the dense water outflow is primarily in the form of cyclonic eddies. The trough serves as a topographic guide that organizes the offshore-moving dense water eddies into a chain pattern. The offshore migration speed of the dense water eddies is similar to the velocity of the dense water offshore flow in the trough, which scaling analysis finds to be proportional to the reduced gravity of the dense water and the slope of the trough side walls and to be inversely proportional to the Coriolis parameter. Our model simulations indicate that, as these cyclonic dense water eddies move across the trough mouth into the deep ocean, they entrain CDW from offshore and carry CDW clockwise along their periphery into the trough. Subsequent cyclonic dense water eddies then entrain the intruding CDW further toward the coast along the trough. This process of recurring onshore entrainment of CDW by a topographically constrained chain of offshore-flowing dense water eddies is consistent with topographic hotspots of onshore intrusion of CDW around Antarctica identified by other studies. It can bring CDW from offshore to close to the coast and thus impact the heat flux into Antarctic coastal regions, affecting interactions among ocean, sea ice, and ice shelves.
期刊介绍:
The Journal of Physical Oceanography (JPO) (ISSN: 0022-3670; eISSN: 1520-0485) publishes research related to the physics of the ocean and to processes operating at its boundaries. Observational, theoretical, and modeling studies are all welcome, especially those that focus on elucidating specific physical processes. Papers that investigate interactions with other components of the Earth system (e.g., ocean–atmosphere, physical–biological, and physical–chemical interactions) as well as studies of other fluid systems (e.g., lakes and laboratory tanks) are also invited, as long as their focus is on understanding the ocean or its role in the Earth system.