Kinematic First-Order Calving Law Implies Potential for Abrupt Ice-Shelf Retreat
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
[Lil 72111 Chi "Liili-S -Duvl R^Uiihj]I^ Im^'Isdtirss • Business^Ofiles • Advertising •Magazine A
The Journal of the New Zealand Antarctic Society Vol 17, No. 4, 2000 [lil 72111 chi "Liili-S -duVl r^uiiHj]i^ iM^'isDTirss • Business^ofiles • Advertising •Magazine a . " ^ newsletter publishing • Corporate communications 'V- ■• • Marketingi.. cormtownications • Media relations • Event management x • Financial PR, annual reports P 0 Box 2369 Tel ++64-3-3650344 Christchurch Fax ++64-3-3654255 New Zealand [email protected] ANTARCTIC CONTENTS Shackleton's Voyage Re-enacted Successful season at Cape Roberts Traverses by Women Surfing Antarctica Lone Rower's Attempt Our cover illustration of Shackleton's Hut is courtesy of © Colin Monteath of Hedgehog House and is sourced from his magnificent book Hunting Meteorites 'Antarctica: Beyond the Southern Ocean', published 1996 David Bateman Ltd, reprinted 1997,160pp. Titanic Icebergs Price NZ $50. Volume 17, No. 4, 2000 Looking for 'White Gold' Issue No. 171 ANTARCTIC is published quarterly by the New Tourism Zealand Antarctic Society Inc., ISSN 0003-5327. Editor Vicki Hyde. Please address all editorial enquiries to Warren Winfly 2000 Head, Publisher, 'Antarctic', PO Box 2369, Christchurch, or Tel 03 365 0344, facsimile 03 365 4255, email: [email protected] Riding the Hagglund Printed by Herald Communications, 52 Bank Street, Timaru, New Zealand. The 'Vanda Lake' Boys The Riddle of the Antarctic Peninsula Shackleton's Endurance Exhibition REVIEWS Book review - 'The Endurance' by Caroline Alexander TRIBUTE Harding Dunnett tribute Volume 17, No. 4, 2000 Antarctic NEWS SHACKLETON'S EPIC BOAT VOYAGE RE ENACTED Four men have successfully re-en Television network ROUTE OF THE JOURNEY acted Shackleton's epic 1916 open film crew aboard mak Siidgeorgien boat journey from Elephant Island to ing a documentary of South Georgia, including his climb the re-enactment. -
Ice Dynamics and Stability Analysis of the Ice Shelf-Glacial System on the East Antarctic Peninsula Over the Past Half Century: Multi-Sensor
Ice dynamics and stability analysis of the ice shelf-glacial system on the east Antarctic Peninsula over the past half century: multi-sensor observations and numerical modeling A dissertation submitted to the Graduate School of the University of Cincinnati in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Geography & Geographic Information Science of the College of Arts and Sciences by Shujie Wang B.S., GIS, Sun Yat-sen University, China, 2010 M.A., GIS, Sun Yat-sen University, China, 2012 Committee Chair: Hongxing Liu, Ph.D. March 2018 ABSTRACT The flow dynamics and mass balance of the Antarctic Ice Sheet are intricately linked with the global climate change and sea level rise. The dynamics of the ice shelf – glacial systems are particularly important for dominating the mass balance state of the Antarctic Ice Sheet. The flow velocity fields of outlet glaciers and ice streams dictate the ice discharge rate from the interior ice sheet into the ocean system. One of the vital controls that affect the flow dynamics of the outlet glaciers is the stability of the peripheral ice shelves. It is essential to quantitatively analyze the interconnections between ice shelves and outlet glaciers and the destabilization process of ice shelves in the context of climate warming. This research aims to examine the evolving dynamics and the instability development of the Larsen Ice Shelf – glacial system in the east Antarctic Peninsula, which is a dramatically changing area under the influence of rapid regional warming in recent decades. Previous studies regarding the flow dynamics of the Larsen Ice Shelf – glacial system are limited to some specific sites over a few time periods. -
BAS Science Summaries 2018-2019 Antarctic Field Season
BAS Science Summaries 2018-2019 Antarctic field season BAS Science Summaries 2018-2019 Antarctic field season Introduction This booklet contains the project summaries of field, station and ship-based science that the British Antarctic Survey (BAS) is supporting during the forthcoming 2018/19 Antarctic field season. I think it demonstrates once again the breadth and scale of the science that BAS undertakes and supports. For more detailed information about individual projects please contact the Principal Investigators. There is no doubt that 2018/19 is another challenging field season, and it’s one in which the key focus is on the West Antarctic Ice Sheet (WAIS) and how this has changed in the past, and may change in the future. Three projects, all logistically big in their scale, are BEAMISH, Thwaites and WACSWAIN. They will advance our understanding of the fragility and complexity of the WAIS and how the ice sheets are responding to environmental change, and contributing to global sea-level rise. Please note that only the PIs and field personnel have been listed in this document. PIs appear in capitals and in brackets if they are not present on site, and Field Guides are indicated with an asterisk. Non-BAS personnel are shown in blue. A full list of non-BAS personnel and their affiliated organisations is shown in the Appendix. My thanks to the authors for their contributions, to MAGIC for the field sites map, and to Elaine Fitzcharles and Ali Massey for collating all the material together. Thanks also to members of the Communications Team for the editing and production of this handy summary. -
References the Larsen Shelf
ICE OF CROWN PRINCE GUSTAV CHANNEL, GRAHAM LAND, ANTARCTICA 409 Thus the Larsen Shelf Ice now extends north from Robertson Island into the southern end of the Channel. The position of its eastern edge, north of Robertson Island, is doubtful, but Taylor's party must have crossed it on their journey from Cape Longing to Snow Hill Island. They crossed some rifts when near Cape Foster which Russell says "might possibly open up and act as tide cracks," and it is most likely that the border between shelf and sea ice was somewhere in this area. In mid-September 1948 the edge of the shelf ice was observed to have broken back west wards to within about 24 km. of Cape Sobral. In conclusion, Larsen Shelf Ice, at the present time, extends as one continuous homogeneous sheet of varying thickness, north-eastwards from its previously mapped northern limit near Robertson Island to the Sji:igren Glacier tongue in the southern part of the Channel. Its seaward edge, whose position obviously varies from year to year, may be taken to run from Robertson Island generally north-east towards James Ross Island. North-east of the Sji:igren Glacier tongue landfast sea ice covers the northern part of the Channel and often persists for several seasons. I am indebted to Mr. J . M. Wordie, St. John's College, Cambridge, for much helpful criticism of this paper and also for the interpretation of the sea ice section. I also acknowledge with thanks the permission of the Colonial Office to publish this report. MS. -
The Ice Thickness Distribution of Flask Glacier, Antarctic Peninsula, Determined by Combining Radio-Echo Soundings, Surface Velocity Data and flow Modelling
18 Annals of Glaciology 54(63) 2013 doi: 10.3189/2013AoG63A603 The ice thickness distribution of Flask Glacier, Antarctic Peninsula, determined by combining radio-echo soundings, surface velocity data and flow modelling Daniel FARINOTTI,1 Hugh CORR,2 G. Hilmar GUDMUNDSSON2 1Laboratory of Hydraulics, Hydrology and Glaciology (VAW), Z¨urich, Switzerland E-mail: [email protected] 2British Antarctic Survey, Cambridge, UK ABSTRACT. An interpolated bedrock topography is presented for Flask Glacier, one of the tributaries of the remnant part of the Larsen B ice shelf, Antarctic Peninsula. The ice thickness distribution is derived by combining direct but sparse measurements from airborne radio-echo soundings with indirect estimates obtained from ice-flow modelling. The ice-flow model is applied to a series of transverse profiles, and a first estimate of the bedrock is iteratively adjusted until agreement between modelled and measured surface velocities is achieved. The adjusted bedrock is then used to reinterpret the radio-echo soundings, and the recovered information used to further improve the estimate of the bedrock itself. The ice flux along the glacier center line provides an additional and independent constraint on the ice thickness. The resulting bedrock topography reveals a glacier bed situated mainly below sea level with sections having retrograde slope. The total ice volume of 120 ± 15 km3 for the considered area of 215 km2 corresponds to an average ice thickness of 560 ± 70 m. INTRODUCTION strengths for calculating signal-to-clutter ratios (Holt and ◦ ◦ Flask Glacier (65 47’ S 62 25’ W) is one of the main others, 2006). tributaries flowing into Scar Inlet, the remaining part of the Here the problem of the correct interpretation is addressed Larsen B ice shelf, Antarctic Peninsula. -
The Bedrock Topography of Starbuck Glacier, Antarctic Peninsula, As Determined by Radio-Echo Soundings and Flow Modeling
Published in "Annals of Glaciology 55(67): 22-28, 2014" which should be cited to refer to this work. The bedrock topography of Starbuck Glacier, Antarctic Peninsula, as determined by radio-echo soundings and flow modeling Daniel FARINOTTI,1;2 Edward C. KING,3 Anika ALBRECHT,4 Matthias HUSS,5 G. Hilmar GUDMUNDSSON3;6 1Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zu¨rich, Zu¨rich, Switzerland 2German Research Centre for Geosciences (GFZ), Potsdam, Germany E-mail: [email protected] 3British Antarctic Survey, Natural Environment Research Council, Cambridge, UK 4University of Potsdam, Potsdam, Germany 5Department of Geosciences, University of Fribourg, Fribourg, Switzerland 6State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China ABSTRACT. A glacier-wide ice-thickness distribution and bedrock topography is presented for Starbuck Glacier, Antarctic Peninsula. The results are based on 90 km of ground-based radio-echo sounding lines collected during the 2012/13 field season. Cross-validation with ice-thickness measurements provided by NASA’s IceBridge project reveals excellent agreement. Glacier-wide estimates are derived using a model that calculates distributed ice thickness, calibrated with the radio-echo soundings. Additional constraints are obtained from in situ ice flow-speed measurements and the surface topography. The results indicate a reverse-sloped bed extending from a riegel occurring 5 km upstream of the current grounding line. The deepest parts of the glacier are as much as 500 m below sea level. The calculated total volume of 80.7 Æ 7.2 km3 corresponds to an average ice thickness of 312 Æ 30 m. -
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. -
The Journal of the New Zealand Antarctic Society Vol 16. No. 1, 1998
The Journal of the New Zealand Antarctic Society Vol 16. No. 1, 1998 New _ for Deep- Freeze AIRPORT GATEWAY MOTOR LODGE 'A Warm Welcome for Antarctic Visitors and the Air Guard' On airport bus route to the city centre. Bus stop at gate. Handy to Antarctic Centre and Christchurch International Airport, Burnside and Nunweek Parks, Golf Courses, University, Teachers College, Rental Vehicle Depots, and Orana Park. Top graded Four-Star plus motel for quality of service. Many years of top service to U.S. Military personnel. Airport Courtesy Vehicle. Casino also provides a Courtesy vehicle. Quality apartment style accommodation, one and two bedroom family units. Ground floor and first floor, Honeymoon, Executive, Studio and Access Suites. All units have Telephone, TV, VCR, In-house Video, Full To Ski f~*\ kitchen with microwave .Fields f 1 Airport ovens/stoves and Hairdryers. Some units also have spa baths. SHI By-Pass Smoking and non-smoking South North units. Guest laundries ROYDVALE AVE Breakfast service available To Railway Station Ample off-street parking Central City 10 minutes Conference facilities and Licensed restaurant. FREEPHONE 0800 2 GATEWAY Proprietors Errol & Kathryn Smith 45 Roydvale Avenue, CHRISTCHURCH 8005, Telephone: 03 358 7093, Facsimile: 03 358 3654. Reservation Toll Free: 0800 2 GATEWAY (0800 2 428 3929). Web Home Page Address: nz.com/southis/christchurch/airportgateway Antarctic Contents FORTHCOMING EVENTS LEAD STORY Deep Freeze Command to Air Guard by Warren Head FEATURE Fish & Seabirds Threatened in Southern Ocean by Dillon Burke NEWS NATIONAL PROGRAMMES New Zealand Cover: Nezo Era for Deep Freeze Canada Chile Volume 16, No. -
Kinematic First-Order Calving Law Implies Potential for Abrupt Ice-Shelf
The Cryosphere, 6, 273–286, 2012 www.the-cryosphere.net/6/273/2012/ The Cryosphere doi:10.5194/tc-6-273-2012 © Author(s) 2012. CC Attribution 3.0 License. Kinematic first-order calving law implies potential for abrupt ice-shelf retreat A. Levermann1,2, T. Albrecht1,2, R. Winkelmann1,2, M. A. Martin1,2, M. Haseloff1,3, and I. Joughin4 1Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany 2Institute of Physics, Potsdam University, Potsdam, Germany 3University of British Columbia, Vancouver, Canada 4Polar Science Center, APL, University of Washington, Seattle, Washington, USA Correspondence to: A. Levermann ([email protected]) Received: 28 September 2011 – Published in The Cryosphere Discuss.: 12 October 2011 Revised: 30 January 2012 – Accepted: 21 February 2012 – Published: 13 March 2012 Abstract. Recently observed large-scale disintegration of 1 Introduction Antarctic ice shelves has moved their fronts closer towards grounded ice. In response, ice-sheet discharge into the ocean Recent observations have shown rapid acceleration of lo- has accelerated, contributing to global sea-level rise and em- cal ice streams after the collapse of ice shelves fringing the phasizing the importance of calving-front dynamics. The Antarctic Peninsula, such as Larsen A and B (De Angelis position of the ice front strongly influences the stress field and Skvarca, 2003; Scambos et al., 2004; Rignot et al., 2004; within the entire sheet-shelf-system and thereby the mass Rott et al., 2007; Pritchard and Vaughan, 2007). Lateral drag flow across the grounding line. While theories for an ad- exerted by an ice-shelf’s embayment on the flow yields back vance of the ice-front are readily available, no general rule stresses that restrain grounded ice as long as the ice shelf is exists for its retreat, making it difficult to incorporate the re- intact (Dupont and Alley, 2005, 2006). -
Long-Term Snow Height Variations in Antarctica from GNSS Interferometric Reflectometry
remote sensing Article Long-Term Snow Height Variations in Antarctica from GNSS Interferometric Reflectometry Elisa Pinat 1,* , Pascale Defraigne 1 , Nicolas Bergeot 1,2, Jean-Marie Chevalier 1,2 and Bruno Bertrand 1 1 Royal Observatory of Belgium, 1180 Brussels, Belgium; [email protected] (P.D.); [email protected] (N.B.); [email protected] (J.-M.C.); [email protected] (B.B.) 2 Solar-Terrestrial Center of Excellence, 1180 Brussels, Belgium * Correspondence: [email protected] Abstract: Acquiring reliable estimates of the Antarctic Ice Sheet surface mass balance is essential for trustworthy predictions of its evolution and future contribution to sea level rise. Snow height variations, i.e., the net change of the surface elevation resulting from a combination of surface processes such as snowfall, ablation, and wind redistribution, can provide a unique tool to constrain the uncertainty on mass budget estimations. In this study, GNSS Interferometric Reflectometry (GNSS- IR) is exploited to assess the long-term variations of snow accumulation and ablation processes. Eight antennas belonging to the Polar Earth Observing Network (POLENET) network are considered, together with the ROB1 antenna, deployed in the east part of Antarctica by the Royal Observatory of Belgium. For ROB1, which is located on an ice rise, we highlight an annual variation of snow accumulation in April–May (~30–50 cm) and ablation during spring/summer period. A snow surface elevation velocity of +0.08 ± 0.01 ma−1 is observed in the 2013–2016 period, statistically rejecting the “no trend” null hypothesis. As the POLENET stations are all located on moving glaciers, Citation: Pinat, E.; Defraigne, P.; their associated downhill motion must be corrected for using an elevation model. -
Larsen B Outlet Glaciers from 1995 to 2013 Title Page Abstract Introduction J
Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | The Cryosphere Discuss., 8, 6271–6301, 2014 www.the-cryosphere-discuss.net/8/6271/2014/ doi:10.5194/tcd-8-6271-2014 TCD © Author(s) 2014. CC Attribution 3.0 License. 8, 6271–6301, 2014 This discussion paper is/has been under review for the journal The Cryosphere (TC). Larsen B outlet Please refer to the corresponding final paper in TC if available. glaciers from 1995 to 2013 Evolution of surface velocities and ice J. Wuite et al. discharge of Larsen B outlet glaciers from 1995 to 2013 Title Page Abstract Introduction J. Wuite1, H. Rott1,2, M. Hetzenecker1, D. Floricioiu3, J. De Rydt4, G. H. Gudmundsson4, T. Nagler1, and M. Kern5 Conclusions References Tables Figures 1ENVEO IT GmbH, Innsbruck, Austria 2Institute for Meteorology and Geophysics, University of Innsbruck, Austria 3Institute for Remote Sensing Technology, German Aerospace Center, J I Oberpfaffenhofen, Germany J I 4British Antarctic Survey, Cambridge, UK 5ESA-ESTEC, Noordwijk, the Netherlands Back Close Received: 2 December 2014 – Accepted: 4 December 2014 – Published: 23 December 2014 Full Screen / Esc Correspondence to: J. Wuite ([email protected]) Printer-friendly Version Published by Copernicus Publications on behalf of the European Geosciences Union. Interactive Discussion 6271 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract TCD We use repeat-pass SAR data to produce detailed maps of surface motion covering the glaciers draining into the former Larsen B ice shelf, Antarctic Peninsula, for differ- 8, 6271–6301, 2014 ent epochs between 1995 and 2013. We combine the velocity maps with estimates 5 of ice thickness to analyze fluctuations of ice discharge. -
Mass Loss of Larsen B Tributary Glaciers (Antarctic Peninsula) Unabated Since 2002 Etienne Berthier,1 Ted A
GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L13501, doi:10.1029/2012GL051755, 2012 Mass loss of Larsen B tributary glaciers (Antarctic Peninsula) unabated since 2002 Etienne Berthier,1 Ted A. Scambos,2 and Christopher A. Shuman3 Received 20 March 2012; revised 31 May 2012; accepted 3 June 2012; published 10 July 2012. [1] Ice mass loss continues at a high rate among the large Figure 1) using different assessment methods [Rignot et al., glacier tributaries of the Larsen B Ice Shelf following its 2004; Rott et al., 2011; Shuman et al., 2011]. Nearly a disintegration in 2002. We evaluate recent mass loss by decade after the ice shelf collapsed, reconciling estimates of mapping elevation changes between 2006 and 2010/11 using the NLBTG mass imbalance contribution is essential. differencing of digital elevation models (DEMs). The mea- [3] Three methods are presently available to measure the surement accuracy of these elevation changes is confirmed changes in the mass of an ice sheet, or a portion of it: space by a ‘null test’, subtracting DEMs acquired within a few gravimetry; the mass budget method (MBM); and the geo- weeks. The overall 2006–2010/11 mass loss rate (9.0 Æ detic method (GM). Space gravimetry from the Gravity 2.1 Gt aÀ1) is similar to the 2001/02–2006 rate (8.8 Æ Recovery and Climate Experiment (GRACE) is currently not 1.6 Gt aÀ1), derived using DEM differencing and laser able to resolve mass losses occurring at a length scale of a altimetry. This unchanged overall loss masks a varying few tens of kilometers, the typical size of the NLBTG basins, pattern of thinning and ice loss for individual glacier basins.