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Impact of Increasing Antarctic Ice-Shelf Melting on Southern Ocean Hydrography
Journal of Glaciology, Vol. 58, No. 212, 2012 doi: 10.3189/2012JoG12J009 1191 Impact of increasing Antarctic ice-shelf melting on Southern Ocean hydrography Caixin WANG,1,2 Keguang WANG3 1Department of Physics, University of Helsinki, Helsinki, Finland E-mail: [email protected] 2Norwegian Polar Institute, Tromsø, Norway 3Norwegian Meteorological Institute, Tromsø, Norway ABSTRACT. Southern Ocean hydrography has undergone substantial changes in recent decades, concurrent with an increase in the rate of Antarctic ice-shelf melting (AISM). We investigate the impact of increasing AISM on hydrography through a twin numerical experiment, with and without AISM, using a global coupled sea-ice/ocean climate model. The difference between these simulations gives a qualitative understanding of the impact of increasing AISM on hydrography. It is found that increasing AISM tends to freshen the surface water, warm the intermediate and deep waters, and freshen and warm the bottom water in the Southern Ocean. Such effects are consistent with the recent observed trends, suggesting that increasing AISM is likely a significant contributor to the changes in the Southern Ocean. Our analyses indicate potential positive feedback between hydrography and AISM that would amplify the effect on both Southern Ocean hydrography and Antarctic ice-shelf loss caused by external factors such as changing Southern Hemisphere winds. 1. INTRODUCTION ice thermodynamic model following Semtner (1976). The 8 The Southern Ocean has undergone significant changes in model has a mean resolution of 2 in the horizontal, and recent decades (see review by Jacobs, 2006): for example, 31 vertical layers in the ocean model with grid spacing from rising temperature in the upper 3000 m (Levitus and others, 10 m in the top 100 m to 500 m at the bottom, and 1 (for 2000, 2005; Gille, 2002, 2003), and decreasing salinity in dynamics) or 3 (for thermodynamics) vertical layers in the 8 high-latitude waters (Jacobs and others, 2002; Whitworth, sea-ice model. -
2019 Weddell Sea Expedition
Initial Environmental Evaluation SA Agulhas II in sea ice. Image: Johan Viljoen 1 Submitted to the Polar Regions Department, Foreign and Commonwealth Office, as part of an application for a permit / approval under the UK Antarctic Act 1994. Submitted by: Mr. Oliver Plunket Director Maritime Archaeology Consultants Switzerland AG c/o: Maritime Archaeology Consultants Switzerland AG Baarerstrasse 8, Zug, 6300, Switzerland Final version submitted: September 2018 IEE Prepared by: Dr. Neil Gilbert Director Constantia Consulting Ltd. Christchurch New Zealand 2 Table of contents Table of contents ________________________________________________________________ 3 List of Figures ___________________________________________________________________ 6 List of Tables ___________________________________________________________________ 8 Non-Technical Summary __________________________________________________________ 9 1. Introduction _________________________________________________________________ 18 2. Environmental Impact Assessment Process ________________________________________ 20 2.1 International Requirements ________________________________________________________ 20 2.2 National Requirements ____________________________________________________________ 21 2.3 Applicable ATCM Measures and Resolutions __________________________________________ 22 2.3.1 Non-governmental activities and general operations in Antarctica _______________________________ 22 2.3.2 Scientific research in Antarctica __________________________________________________________ -
S41467-018-05625-3.Pdf
ARTICLE DOI: 10.1038/s41467-018-05625-3 OPEN Holocene reconfiguration and readvance of the East Antarctic Ice Sheet Sarah L. Greenwood 1, Lauren M. Simkins2,3, Anna Ruth W. Halberstadt 2,4, Lindsay O. Prothro2 & John B. Anderson2 How ice sheets respond to changes in their grounding line is important in understanding ice sheet vulnerability to climate and ocean changes. The interplay between regional grounding 1234567890():,; line change and potentially diverse ice flow behaviour of contributing catchments is relevant to an ice sheet’s stability and resilience to change. At the last glacial maximum, marine-based ice streams in the western Ross Sea were fed by numerous catchments draining the East Antarctic Ice Sheet. Here we present geomorphological and acoustic stratigraphic evidence of ice sheet reorganisation in the South Victoria Land (SVL) sector of the western Ross Sea. The opening of a grounding line embayment unzipped ice sheet sub-sectors, enabled an ice flow direction change and triggered enhanced flow from SVL outlet glaciers. These relatively small catchments behaved independently of regional grounding line retreat, instead driving an ice sheet readvance that delivered a significant volume of ice to the ocean and was sustained for centuries. 1 Department of Geological Sciences, Stockholm University, Stockholm 10691, Sweden. 2 Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX 77005, USA. 3 Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904, USA. 4 Department -
Basal Crevasses on the Larsen C Ice Shelf, Antarctica
GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L16504, doi:10.1029/2012GL052413, 2012 Basal crevasses on the Larsen C Ice Shelf, Antarctica: Implications for meltwater ponding and hydrofracture Daniel McGrath,1 Konrad Steffen,1 Harihar Rajaram,2 Ted Scambos,3 Waleed Abdalati,1,4 and Eric Rignot5,6 Received 1 June 2012; revised 20 July 2012; accepted 23 July 2012; published 29 August 2012. [1] A key mechanism for the rapid collapse of both the Lar- thickness (due to the density difference between water and sen A and B Ice Shelves was meltwater-driven crevasse ice), fracturing the ice shelf into numerous elongate icebergs propagation. Basal crevasses, large-scale structural features [van der Veen, 1998, 2007; Scambos et al., 2003, 2009; within ice shelves, may have contributed to this mechanism in Weertman, 1973]. The narrow along-flow width and elon- three important ways: i) the shelf surface deforms due to gated across-flow length of these icebergs distinguishes them modified buoyancy and gravitational forces above the basal from tabular icebergs, and likely facilitates a positive feed- crevasse, creating >10 m deep compressional surface depres- back during the disintegration process, as elongate icebergs sions where meltwater can collect, ii) bending stresses from overturn and initiate further ice shelf calving [MacAyeal the modified shape drive surface crevassing, with crevasses et al., 2003; Guttenberg et al., 2011; Burton et al., 2012]. reaching 40 m in width, on the flanks of the basal-crevasse- [3] Dramatic atmospheric warming over the past five dec- induced trough and iii) the ice thickness is substantially ades has increased surface meltwater production along the reduced, thereby minimizing the propagation distance before a Antarctic Peninsula (AP) [Vaughan et al.,2003;van den full-thickness rift is created. -
Ice on Earth – Download
Ice on Earth: & By Sea By Land ce is found on every continent and ocean basin, from the highest peak in Africa to the icy North and South Poles. Almost two-thirds of all fresh water is trapped in ice. Scientists study Earth’s ice Ibecause it can affect the amount of fresh water available in our rivers, lakes, and reservoirs. Earth scientists study two types of ice on the Earth’s surface: land ice and sea ice. Land ice forms when snow piles up year after year, then gets compressed and hardens. Ice sheets and glaciers on Greenland and Antarctica hold much of our planet's land ice. Sea ice forms when sea water freezes and is found in the Arctic Ocean, the Southern Ocean around Antarctica, and other cold regions. Monitoring Ice from Space —clouds Much of Earth’s ice is found in remote and dangerous places. NASA uses sensors on satellites and airplanes to measure ice clouds— in places that are hard to visit. Satellite images also provide scientists with a global view of how ice is changing on our planet. — sea ice sea ice— Greenland Melting Ice (land ice) Light-colored surfaces that reflect more sun- light have a high albedo, IMAGE: Earth Observatory and dark surfaces that absorb more sunlight On July 11, 2011, NASA’s Terra satellite IMAGE: NASA captured this image of the north polar have a lower albedo. Ice region. Natural-color images of ice on reflects a lot of sunlight the Arctic Ocean can be compared with back into space; it has a high albedo. -
Ice Sheet Stability - Istar
Ice Sheet Stability - iSTAR Science Plan 1. Summary Limitations in our understanding of ice sheet dynamics mean that models are currently unable to adequately describe contemporary ice mass loss rates. The result is that they cannot provide confident predictions of future mass loss rates. Such predictions and their resultant impact on sea-level rise estimates are important for both climate modellers and coastal planners. The £7.4M NERC programme on Ice Sheet Stability is a response to the requirement to provide better projections of future ice sheet stability. 2. The Research Programme’s Objective The objective of this programme is to improve understanding of the key ice sheet and ocean processes that affect ice sheet stability, and to enable the incorporation of this understanding into models leading to an improved ability to predict future ice sheet behaviour. The programme will focus on the West Antarctic Ice Sheet, with an emphasis in the Amundsen Sea sector and Pine Island Glacier. 3. Scientific Background The great ice sheets of Antarctica contain major reservoirs of freshwater. Changes in these ice sheets will induce large changes in global sea level and in freshwater flux to the oceans, which in turn can affect ocean circulation and climate. Although many factors contribute to sea level rise, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change identified the cryosphere as the largest source of uncertainty in predictions of future sea level rise over the 50-200 year time horizon. There is evidence from the geological record of rapid changes in sea level that imply dramatic changes in the Antarctic ice sheets. -
On the Disintegration of Ice Shelves: the Role of Fracture Terence J
The University of Maine DigitalCommons@UMaine Earth Science Faculty Scholarship Earth Sciences 1983 On the Disintegration of Ice Shelves: The Role of Fracture Terence J. Hughes University of Maine - Main, [email protected] Follow this and additional works at: https://digitalcommons.library.umaine.edu/ers_facpub Part of the Earth Sciences Commons Repository Citation Hughes, Terence J., "On the Disintegration of Ice Shelves: The Role of Fracture" (1983). Earth Science Faculty Scholarship. 63. https://digitalcommons.library.umaine.edu/ers_facpub/63 This Article is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Earth Science Faculty Scholarship by an authorized administrator of DigitalCommons@UMaine. For more information, please contact [email protected]. Vol. JoumalojGlac;ology, 29. 101. 1983 No. ON THE DISINTEGRATION OF ICE SHELVES: THE ROLE OF FRACTURE By T. HUGHES (Department of Geological Sciences and Institute for Quarternary Studies, University of Maine at Orono, Orono, Maine 04469, U.S. A.) ABSTRACT. Crevasses can be ignored in studying the dynamics of most glaciers because they are only about 20 m deep, a small fraction of ice thickness. In ice shelves, ho wever, surface crevasses 20 m deep often reach sea level and bottom crevasses can move upward to sea-level (Clough, 1974; Weertman, 1980). The ice shelf is fractured completely through if surface and basal crevasses meet (Barrett, 1975; Hughes, 1979). This is especially likely if surface melt water fills surface crevasses (Weertman, 1973; Pfeffer, 1982; Fastook and Schmidt, 1982). Fracture may therefore play an important role in the disintegration of ice shelves. -
Ice Shelf Flubber Activity FAR 2016
How Do Ice Shelves Affect Sea Level Rise?: Using Flubber to Model Ice Shelf/Glacier Interactions Grade Level: 6 - 8 Minutes: 15 - 60 min Subject: earth science, physical science Activity type: model, lab, earth dynamics NGSS Connections: Performance Expectations: - MS-ESS2- Earth’s Systems Science and Engineering Practices: - Developing and Using Models https://upload.wikimedia.org/wikipedia/co mmons/1/10/Map-antarctica-ross-ice- shelf-red-x.png Meet the scientist: Lynn Kaluzienski is a student research scientist with the Climate Change Institute at the University of Maine. Lynn is a glaciologist and will be conducting field research and gathering data to better understand changes occurring in the Ross Ice Shelf, which happens to be the largest ice shelf in Antarctica. Using the data she collects, Lynn will develop a model to make predictions about the future of the Ross Ice Shelf and its effect on sea level rise. Follow her mission through the 4-H Follow a Researcher™ program (https://extension.umaine.edu/4h/youth/follow-a-researcher/)! What’s an ice shelf? Ice shelves are thick slabs of ice floating on water, formed by glaciers and ice sheets that flow from land towards the coastline. Ice shelves are constantly pushed out into the sea by the glaciers behind them, but instead of growing continuously into the ocean as they advance, chunks of ice shelves are broken off to form icebergs in a process called calving. Warm ocean water also causes the underside of an ice shelf to melt. Despite what you might expect, the sea level does not rise when ice shelves melt and break apart since they are already floating on the ocean surface. -
Halleyvi Draft Cee.Pdf
COVER: Artist’s impressions of concept designs for Halley VI Research Station. From top: Hopkins/Expedition/atelier ten – ‘walking’ buildings using hydraulic legs; FaberMaunsell and Hugh Broughton – modular buildings and service pods on skis; and Buro Happold and Lifschutz Davidson – ‘icecraft’ buildings on telescopic legs. DRAFT CEE HALLEY VI CONTENTS CONTENTS NON-TECHNICAL SUMMARY ............................................................................................................................. i 1. Introduction ...............................................................................................................................................1 1.1 The role of Halley Research Station............................................................................................................1 1.2 History of Halley Research Station .............................................................................................................2 1.3 Scientific research at Halley ........................................................................................................................4 1.4 The future development of Halley...............................................................................................................5 1.5 Preparation and production of the CEE for Halley VI.................................................................................7 2. Description of the proposed activity ........................................................................................................9 -
6. ANTARCTICA and the SOUTHERN OCEAN—T. Scambos
6. ANTARCTICA AND THE SOUTHERN anomalies continued to persist over the Antarctic OCEAN—T. Scambos and S. Stammerjohn, Eds. Peninsula. In conjunction with negative southern a. Overview—T. Scambos and S. Stammerjohn annular mode (SAM) index values that contrasted The year 2018 was marked by extreme seasonal and with positive values both before and after this pe- regional climate anomalies in Antarctica and across riod, positive pressure anomalies emerged over the the Southern Ocean, expressed by episodes of record continental interior, producing widespread high high temperatures on the high Antarctic Plateau and temperatures across the ice sheet interior, with record record low sea ice extents, most notably in the Wed- highs observed at several continental stations (Relay dell and Ross Seas. For the Antarctic continent as a Station AWS, Amundsen–Scott South Pole Station). whole, 2018 was warmer than average, particularly Circumpolar sea ice extent remained well below aver- near the South Pole (~3°C above the 1981–2010 refer- age throughout the year, as has been the case since ence period), Dronning Maud Land (1° to 2°C above September 2016. average), and the Ross Ice Shelf and Ross Sea (also 1° to In spring (October), a strong but short-lived wave- 2°C above average). In contrast, and despite conducive three pattern developed, producing strong regional conditions for its formation, the ozone hole at its maxi- contrasts in temperature and pressure anomalies. At mum extent was near the mean for 2000–18, likely due the same time, the stratospheric vortex intensified, to an ongoing slow decline in stratospheric chlorine but due to decreasing ClO in the stratosphere, the monoxide (ClO) concentration. -
Edinburgh Research Explorer
Edinburgh Research Explorer Antarctic ice rises and rumples Citation for published version: Matsuoka, K, Hindmarsh, RCA, Moholdt, G, Bentley, MJ, Pritchard, HD, Brown, J, Conway, H, Drews, R, Durand, G, Goldberg, D, Hattermann, T, Kingslake, J, Lenaerts, JTM, Martín, C, Mulvaney, R, Nicholls, KW, Pattyn, F, Ross, N, Scambos, T & Whitehouse, PL 2015, 'Antarctic ice rises and rumples: Their properties and significance for ice-sheet dynamics and evolution', Earth-Science Reviews, vol. 150, pp. 724-745. https://doi.org/10.1016/j.earscirev.2015.09.004 Digital Object Identifier (DOI): 10.1016/j.earscirev.2015.09.004 Link: Link to publication record in Edinburgh Research Explorer Document Version: Publisher's PDF, also known as Version of record Published In: Earth-Science Reviews General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 11. Oct. 2021 Earth-Science Reviews 150 (2015) 724–745 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Antarctic ice rises and rumples: Their properties and significance for ice-sheet dynamics and evolution Kenichi Matsuoka a,⁎, Richard C.A. -
The Larsen Ice Shelf System, Antarctica
22–25 Sept. GSA 2019 Annual Meeting & Exposition VOL. 29, NO. 8 | AUGUST 2019 The Larsen Ice Shelf System, Antarctica (LARISSA): Polar Systems Bound Together, Changing Fast The Larsen Ice Shelf System, Antarctica (LARISSA): Polar Systems Bound Together, Changing Fast Julia S. Wellner, University of Houston, Dept. of Earth and Atmospheric Sciences, Science & Research Building 1, 3507 Cullen Blvd., Room 214, Houston, Texas 77204-5008, USA; Ted Scambos, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80303, USA; Eugene W. Domack*, College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, Florida 33701-1567, USA; Maria Vernet, Scripps Institution of Oceanography, University of California San Diego, 8622 Kennel Way, La Jolla, California 92037, USA; Amy Leventer, Colgate University, 421 Ho Science Center, 13 Oak Drive, Hamilton, New York 13346, USA; Greg Balco, Berkeley Geochronology Center, 2455 Ridge Road, Berkeley , California 94709, USA; Stefanie Brachfeld, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, USA; Mattias R. Cape, University of Washington, School of Oceanography, Box 357940, Seattle, Washington 98195, USA; Bruce Huber, Lamont-Doherty Earth Observatory, Columbia University, 61 US-9W, Palisades, New York 10964, USA; Scott Ishman, Southern Illinois University, 1263 Lincoln Drive, Carbondale, Illinois 62901, USA; Michael L. McCormick, Hamilton College, 198 College Hill Road, Clinton, New York 13323, USA; Ellen Mosley-Thompson, Dept. of Geography, Ohio State University, 1036 Derby Hall, 154 North Oval Mall, Columbus, Ohio 43210, USA; Erin C. Pettit#, University of Alaska Fairbanks, Dept. of Geosciences, 900 Yukon Drive, Fairbanks, Alaska 99775, USA; Craig R.