1
|
Lawrence JD, Washam PM, Stevens C, Hulbe C, Horgan HJ, Dunbar G, Calkin T, Stewart C, Robinson N, Mullen AD, Meister MR, Hurwitz BC, Quartini E, Dichek DJG, Spears A, Schmidt BE. Crevasse refreezing and signatures of retreat observed at Kamb Ice Stream grounding zone. Nat Geosci 2023; 16:238-243. [PMID: 36920161 PMCID: PMC10005960 DOI: 10.1038/s41561-023-01129-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Ice streams flowing into Ross Ice Shelf are presently responsible for around 10% of the mass flux from West Antarctica, with the noteworthy exception of Kamb Ice Stream, which stagnated in the late 1800s. The subsequent reduction in ice supply led to grounding-line retreat at the coastal margin where Kamb transitions into the floating Ross Ice Shelf. Grounding-line migration is linked to broader changes in ice-sheet mass balance and sea level, but our understanding of related ice, ocean and seafloor interactions is limited by the difficulty in accessing these remote regions. Here we report in situ observations from an underwater vehicle deployed at Kamb that show how fine-scale variability in ice and ocean structure combine to influence a diversity of ice-ocean interactions. We found a stratified water column within a tenth of a degree of freezing at the ice base and mapped basal crevasses with supercooled water and active marine ice formation. At the seafloor, we interpret parallel ridges as crevasse impressions left as the ice lifted off during grounding-line retreat. These observations from a recently ungrounded sub-shelf environment illuminate both the geomorphological signatures of past grounding-line retreat and the fine-scale sensitivity of ongoing ice-ocean interactions to ice topography.
Collapse
Affiliation(s)
- J. D. Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Honeybee Robotics, Exploration Systems, Altadena, CA USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - P. M. Washam
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - C. Stevens
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
- Department of Physics, University of Auckland, Auckland, New Zealand
| | - C. Hulbe
- School of Surveying, University of Otago, Dunedin, New Zealand
| | - H. J. Horgan
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - G. Dunbar
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - T. Calkin
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - C. Stewart
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
| | - N. Robinson
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
| | - A. D. Mullen
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - M. R. Meister
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - B. C. Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - E. Quartini
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - D. J. G. Dichek
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - A. Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - B. E. Schmidt
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| |
Collapse
|
2
|
Schmidt BE, Washam P, Davis PED, Nicholls KW, Holland DM, Lawrence JD, Riverman KL, Smith JA, Spears A, Dichek DJG, Mullen AD, Clyne E, Yeager B, Anker P, Meister MR, Hurwitz BC, Quartini ES, Bryson FE, Basinski-Ferris A, Thomas C, Wake J, Vaughan DG, Anandakrishnan S, Rignot E, Paden J, Makinson K. Publisher Correction: Heterogeneous melting near the Thwaites Glacier grounding line. Nature 2023; 615:E21. [PMID: 36829047 PMCID: PMC10017506 DOI: 10.1038/s41586-023-05861-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Affiliation(s)
- B E Schmidt
- Department of Astronomy, Cornell University, Ithaca, NY, USA. .,Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA.
| | - P Washam
- Department of Astronomy, Cornell University, Ithaca, NY, USA.,Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | | | | | - D M Holland
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA.,Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - J D Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - K L Riverman
- Department of Environmental Studies, University of Portland, Portland, OR, USA
| | - J A Smith
- British Antarctic Survey, Cambridge, UK
| | - A Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - D J G Dichek
- Department of Astronomy, Cornell University, Ithaca, NY, USA.,Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - A D Mullen
- Department of Astronomy, Cornell University, Ithaca, NY, USA.,Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - E Clyne
- Department of Geosciences, Pennsylvania State University, State College, PA, USA.,Environmental Studies, Lewis & Clark College, Portland, OR, USA
| | - B Yeager
- Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - P Anker
- British Antarctic Survey, Cambridge, UK
| | - M R Meister
- Department of Astronomy, Cornell University, Ithaca, NY, USA.,Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - B C Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - E S Quartini
- Department of Astronomy, Cornell University, Ithaca, NY, USA.,Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - F E Bryson
- Department of Astronomy, Cornell University, Ithaca, NY, USA.,Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA.,School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - A Basinski-Ferris
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
| | - C Thomas
- British Antarctic Survey, Cambridge, UK
| | - J Wake
- British Antarctic Survey, Cambridge, UK
| | | | - S Anandakrishnan
- Department of Geosciences, Pennsylvania State University, State College, PA, USA
| | - E Rignot
- Department of Earth System Science, University of California, Irvine, Irvine, CA, USA
| | - J Paden
- Center for Remote Sensing and Integrated Systems, University of Kansas, Lawrence, KS, USA
| | | |
Collapse
|
3
|
Schmidt BE, Washam P, Davis PED, Nicholls KW, Holland DM, Lawrence JD, Riverman KL, Smith JA, Spears A, Dichek DJG, Mullen AD, Clyne E, Yeager B, Anker P, Meister MR, Hurwitz BC, Quartini ES, Bryson FE, Basinski-Ferris A, Thomas C, Wake J, Vaughan DG, Anandakrishnan S, Rignot E, Paden J, Makinson K. Heterogeneous melting near the Thwaites Glacier grounding line. Nature 2023; 614:471-478. [PMID: 36792738 PMCID: PMC9931587 DOI: 10.1038/s41586-022-05691-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 12/22/2022] [Indexed: 02/17/2023]
Abstract
Thwaites Glacier represents 15% of the ice discharge from the West Antarctic Ice Sheet and influences a wider catchment1-3. Because it is grounded below sea level4,5, Thwaites Glacier is thought to be susceptible to runaway retreat triggered at the grounding line (GL) at which the glacier reaches the ocean6,7. Recent ice-flow acceleration2,8 and retreat of the ice front8-10 and GL11,12 indicate that ice loss will continue. The relative impacts of mechanisms underlying recent retreat are however uncertain. Here we show sustained GL retreat from at least 2011 to 2020 and resolve mechanisms of ice-shelf melt at the submetre scale. Our conclusions are based on observations of the Thwaites Eastern Ice Shelf (TEIS) from an underwater vehicle, extending from the GL to 3 km oceanward and from the ice-ocean interface to the sea floor. These observations show a rough ice base above a sea floor sloping upward towards the GL and an ocean cavity in which the warmest water exceeds 2 °C above freezing. Data closest to the ice base show that enhanced melting occurs along sloped surfaces that initiate near the GL and evolve into steep-sided terraces. This pronounced melting along steep ice faces, including in crevasses, produces stratification that suppresses melt along flat interfaces. These data imply that slope-dependent melting sculpts the ice base and acts as an important response to ocean warming.
Collapse
Affiliation(s)
- B E Schmidt
- Department of Astronomy, Cornell University, Ithaca, NY, USA.
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA.
| | - P Washam
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | | | | | - D M Holland
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
- Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - J D Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - K L Riverman
- Department of Environmental Studies, University of Portland, Portland, OR, USA
| | - J A Smith
- British Antarctic Survey, Cambridge, UK
| | - A Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - D J G Dichek
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - A D Mullen
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - E Clyne
- Department of Geosciences, Pennsylvania State University, State College, PA, USA
- Environmental Studies, Lewis & Clark College, Portland, OR, USA
| | - B Yeager
- Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - P Anker
- British Antarctic Survey, Cambridge, UK
| | - M R Meister
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - B C Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - E S Quartini
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - F E Bryson
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - A Basinski-Ferris
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
| | - C Thomas
- British Antarctic Survey, Cambridge, UK
| | - J Wake
- British Antarctic Survey, Cambridge, UK
| | | | - S Anandakrishnan
- Department of Geosciences, Pennsylvania State University, State College, PA, USA
| | - E Rignot
- Department of Earth System Science, University of California, Irvine, Irvine, CA, USA
| | - J Paden
- Center for Remote Sensing and Integrated Systems, University of Kansas, Lawrence, KS, USA
| | | |
Collapse
|