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Park T, Nakayama Y, Nam S. Amundsen Sea circulation controls bottom upwelling and Antarctic Pine Island and Thwaites ice shelf melting. Nat Commun 2024; 15:2946. [PMID: 38605000 PMCID: PMC11009355 DOI: 10.1038/s41467-024-47084-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 03/15/2024] [Indexed: 04/13/2024] Open
Abstract
The Pine Island and Thwaites Ice Shelves (PIIS/TIS) in the Amundsen Sea are melting rapidly and impacting global sea levels. The thermocline depth (TD) variability, the interface between cold Winter Water and warm modified Circumpolar Deep Water (mCDW), at the PIIS/TIS front strongly correlates with basal melt rates, but the drivers of its interannual variability remain uncertain. Here, using an ocean model, we propose that the strength of the eastern Amundsen Sea on-shelf circulation primarily controls TD variability and consequent PIIS/TIS melt rates. The TD variability occurs because the on-shelf circulation meanders following the submarine glacial trough, creating vertical velocity through bottom Ekman dynamics. We suggest that a strong or weak ocean circulation, possibly linked to remote winds in the Bellingshausen Sea, generates corresponding changes in bottom Ekman convergence, which modulates mCDW upwelling and TD variability. We show that interannual variability of off-shelf zonal winds has a minor effect on ocean heat intrusion into PIIS/TIS cavities, contrary to the widely accepted concept.
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Affiliation(s)
- Taewook Park
- Division of Ocean and Atmosphere Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
| | - Yoshihiro Nakayama
- Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan.
| | - SungHyun Nam
- School of Earth and Environmental Sciences/Research Institute of Oceanography, Seoul National University, Gwanak-gu, Seoul, 08826, Republic of Korea
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Wekerle C, McPherson R, von Appen WJ, Wang Q, Timmermann R, Scholz P, Danilov S, Shu Q, Kanzow T. Atlantic Water warming increases melt below Northeast Greenland's last floating ice tongue. Nat Commun 2024; 15:1336. [PMID: 38378701 PMCID: PMC10879102 DOI: 10.1038/s41467-024-45650-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/29/2024] [Indexed: 02/22/2024] Open
Abstract
The 79 North Glacier (79NG) features Greenland's largest floating ice tongue. Even though its extent has not changed significantly in recent years, observations have indicated a major thinning of the ice tongue from below. Both ocean warming and an increase in subglacial discharge from the ice sheet induced by atmospheric warming could increase the basal melt; however, available observations alone cannot tell which of these is the main driver. Here, we employ a global simulation which explicitly resolves the ocean circulation in the cavity with 700 m resolution to disentangle the impact of the ocean and atmosphere. We find that the interannual variability of basal melt below 79NG over the past 50 years is mainly associated with changes in the temperature of the Atlantic Intermediate Water inflow, which can be traced back across the Northeast Greenland continental shelf to the eastern Fram Strait with a lag of 3 years.
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Affiliation(s)
- Claudia Wekerle
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.
| | - Rebecca McPherson
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Wilken-Jon von Appen
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Qiang Wang
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Ralph Timmermann
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Patrick Scholz
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Sergey Danilov
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Department of Mathematics and Logistics, Constuctor University, Bremen, Germany
| | - Qi Shu
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China
| | - Torsten Kanzow
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- University of Bremen, Bremen, Germany
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Soderlund KM, Rovira-Navarro M, Le Bars M, Schmidt BE, Gerkema T. The Physical Oceanography of Ice-Covered Moons. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:25-53. [PMID: 37669566 DOI: 10.1146/annurev-marine-040323-101355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
In the outer solar system, a growing number of giant planet satellites are now known to be abodes for global oceans hidden below an outer layer of ice. These planetary oceans are a natural laboratory for studying physical oceanographic processes in settings that challenge traditional assumptions made for Earth's oceans. While some driving mechanisms are common to both systems, such as buoyancy-driven flows and tides, others, such as libration, precession, and electromagnetic pumping, are likely more significant for moons in orbit around a host planet. Here, we review these mechanisms and how they may operate across the solar system, including their implications for ice-ocean interactions. Future studies should continue to advance our understanding of each of these processes as well as how they may act together in concert. This interplay also has strong implications for habitability as well as testing oceanic hypotheses with future missions.
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Affiliation(s)
- Krista M Soderlund
- Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, USA;
| | - Marc Rovira-Navarro
- Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA;
| | - Michael Le Bars
- CNRS, Aix Marseille Univ, Centrale Marseille, IRPHE, Marseille, France;
| | - Britney E Schmidt
- Departments of Astronomy and of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York, USA;
| | - Theo Gerkema
- Department of Estuarine and Delta Systems, NIOZ Royal Netherlands Institute for Sea Research, Yerseke, The Netherlands;
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Washam P, Lawrence JD, Stevens CL, Hulbe CL, Horgan HJ, Robinson NJ, Stewart CL, Spears A, Quartini E, Hurwitz B, Meister MR, Mullen AD, Dichek DJ, Bryson F, Schmidt BE. Direct observations of melting, freezing, and ocean circulation in an ice shelf basal crevasse. SCIENCE ADVANCES 2023; 9:eadi7638. [PMID: 37889975 PMCID: PMC10610921 DOI: 10.1126/sciadv.adi7638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023]
Abstract
Ocean conditions near the grounding zones of Antarctica's ice shelves play a key role in controlling the outflow and mass balance of the ice sheet. However, ocean observations in these regions are largely absent. Here, we present a detailed spatial survey collected with an underwater vehicle in a basal crevasse located in the ocean cavity at the Ross Ice Shelf grounding zone. The observations depict fine-scale variability in ocean forcing that drives asymmetric melting along the lower crevasse sidewalls and freezing in the upper reaches of the crevasse. Freshwater release from melting at depth and salt rejection from freezing above drives an overturning circulation. This vertical circulation pattern overlays a dominant throughflow jet, which funnels water parallel to the coastline, orthogonal to the direction of tidal currents. Importantly, these data reveal that basal crevasses influence ocean circulation and mixing at ice shelf grounding zones to an extent previously unknown.
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Affiliation(s)
- Peter Washam
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Craig L. Stevens
- Ocean Dynamics Group, National Institute for Water and Atmospheric Research, Greta Point, Wellington, New Zealand
- Department of Physics, University of Auckland, Auckland, New Zealand
| | | | - Huw J. Horgan
- Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland
- Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL), Birmensdorf, Switzerland
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - Natalie J. Robinson
- Ocean Dynamics Group, National Institute for Water and Atmospheric Research, Greta Point, Wellington, New Zealand
| | - Craig L. Stewart
- Ocean Dynamics Group, National Institute for Water and Atmospheric Research, Greta Point, Wellington, New Zealand
| | - Anthony Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Enrica Quartini
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - Benjamin Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Matthew R. Meister
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | | | | | - Frances Bryson
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - Britney E. Schmidt
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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