Iceberg calving rates from northern Ellesmere Island ice caps, Canadian Arctic, 1999–2003

Abstract Optical satellite imagery was used to estimate glacier surface velocities and iceberg calving rates from Agassiz and western Grant Ice Caps, Nunavut, Canada, between 1999 and 2003. The largest mean annual surface velocities ranged from ∼400 to 700 m a−1, but velocities in the ∼100–200 m a−1 range were common. Summer velocities were up to an order of magnitude larger than annually averaged velocities. The highest velocity (∼1530 m a−1) was measured on the floating tongue of Lake Tuborg Glacier between 19 July and 19 August 2001. Calving rates from individual glaciers varied by up to a factor of two between successive years. Summer calving rates were ∼2–8 times larger than annual average rates. The average ratio of the calving flux due to terminus-volume change to that due to ice flow through the glacier terminus was ∼0.81 for the annual rates and ∼1.71 for summer rates. The estimated mean annual calving rate from Agassiz Ice Cap in the period 1999–2002 was 0.67 ± 0.15 km3 a−1, of which ∼54% emanated from Eugenie Glacier alone. This total rate is similar to a previously estimated calving rate from Devon Ice Cap.

[1]  James K. Yungel,et al.  Elevation changes of ice caps in the Canadian Arctic Archipelago , 2004 .

[2]  Robert Bingham,et al.  Intra-annual and intra-seasonal flow dynamics of a High Arctic polythermal valley glacier , 2003, Annals of Glaciology.

[3]  R. Armstrong,et al.  The Physics of Glaciers , 1981 .

[4]  R. Koerner.  Glaciers of the arctic Islands glaciers of the High Arctic Islands , 2002 .

[5]  M. Sharp,et al.  Recent Changes in Areal Extent of the Devon Ice Cap, Nunavut, Canada , 2004 .

[6]  Luke Copland,et al.  The distribution and flow characteristics of surge-type glaciers in the Canadian High Arctic , 2003, Annals of Glaciology.

[7]  J. G. Ferrigno,et al.  SATELLITE IMAGE ATLAS OF GLACIERS OF THE WORLD: NORTH AMERICA. Richard S. Williams Jr and Jane G. Ferrigno (Editors). 2002. Washington, DC: US Government Printing Office (US Geological Survey Professional Paper 1386-J). xii+405 p, illustrated, soft cover. ISBN 0-607-98290-X. , 2004, Polar Record.

[8]  N. Reeh,et al.  Sea ice and the stability of north and northeast Greenland floating glaciers , 2001, Annals of Glaciology.

[9]  Tavi Murray,et al.  Seasonal variation in velocity before retreat of Jakobshavn Isbræ, Greenland , 2005 .

[10]  J. Dowdeswell,et al.  A surge of Perseibreen, Svalbard, examined using aerial photography and ASTER high resolution satellite imagery , 2003 .

[11]  M. Sharp,et al.  Flow dynamics and iceberg calving rates of Devon Ice Cap, Nunavut, Canada , 2005, Journal of Glaciology.

[12]  G. Hattersley-Smith.  Recent observations on the surging Otto Glacier, Ellesmere Island , 1969 .

[13]  S. P. Anderson,et al.  Glaciers Dominate Eustatic Sea-Level Rise in the 21st Century , 2007, Science.

[14]  J. Hagen,et al.  Mass Balance of the Cryosphere: Arctic ice caps and glaciers , 2004 .

[15]  J. Hagen,et al.  On the Net Mass Balance of the Glaciers and Ice Caps in Svalbard, Norwegian Arctic , 2003 .

[16]  Luke Copland,et al.  Links between short-term velocity variations and the subglacial hydrology of a predominantly cold polythermal glacier , 2003, Journal of Glaciology.

[17]  Julian A. Dowdeswell,et al.  Form and flow of the Devon Island Ice Cap, Canadian Arctic , 2004 .

[18]  J. G. Ferrigno,et al.  Velocities of antarctic outlet glaciers determined from sequential Landsat images , 1989 .

[19]  J. F. Nye.  The flow of a glacier in a channel of rectangular, elliptic or parabolic cross-section , 1965 .

[20]  Julian A. Dowdeswell,et al.  A surge of Perseibreen, Svalbard, examined using aerial photography and ASTER high resolution satellite imagery , 2003 .

[21]  B. L. Beattie,et al.  Surface Melt-Induced Acceleration of Greenland Ice-Sheet Flow , 2002 .

[22]  A. Iken.  Measurements of water pressure in moulins as part of a movement study of the White Glacier, Axel Heiberg Island, Northwest Territories, Canada , 1972 .

[23]  Liestoel Olav.  Glaciological work in 1975 , 1975 .

[24]  Mark F. Meier,et al.  GLACIERS AND THE CHANGING EARTH SYSTEM: A 2004 SNAPSHOT , 2010 .

[25]  R. Koerner,et al.  Mass balance of glaciers in the Queen Elizabeth Islands, Nunavut, Canada , 2005, Annals of Glaciology.

[26]  R. Bindschadler,et al.  Application of image cross-correlation to the measurement of glacier velocity using satellite image data , 1992 .

[27]  C. Doake,et al.  Is Vertical Shear in an Ice Shelf Negligible? , 1979, Journal of Glaciology.

[28]  H. P. Trettin.  The Arctic Islands , 1989 .

[29]  A. Shepherd,et al.  Form and flow of the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian High Arctic , 2002 .

[30]  A. Gardner,et al.  Influence of the Arctic Circumpolar Vortex on the Mass Balance of Canadian High Arctic Glaciers , 2007 .

[31]  N H Short,et al.  Glacier dynamics in the Canadian High Arctic from RADARSAT-1 speckle tracking , 2005 .

[32]  Ian Joughin,et al.  Large fluctuations in speed on Greenland's Jakobshavn Isbræ glacier , 2004, Nature.

[33]  M. Noguer,et al.  Climate change 2001: The scientific basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change , 2002 .