Ice flow in Greenland for the International Polar Year 2008–2009

A digital representation of ice surface velocity is essential for a variety of glaciological, geologic and geophysical analyses and modeling. Here, we present a new, reference, comprehensive, high-resolution, digital mosaic of ice motion in Greenland assembled from satellite radar interferometry data acquired during the International Polar Year 2008 to 2009 by the Envisat Advanced Synthetic-Aperture Radar (ASAR), the Advanced Land Observation System (ALOS)'s Phase-Array L-band SAR (PALSAR) and the RADARSAT-1 SAR that covers 99% of the ice sheet in area. The best mapping performance is obtained using ALOS PALSAR data due to higher levels of temporal coherence at the L-band frequency; but C-band frequency SAR data are less affected by the ionosphere. The ice motion map reveals various flow regimes, ranging from patterned enhanced flow into a few large glaciers in the cold, low precipitation areas of north Greenland; to diffuse, enhanced flow into numerous, narrow, fast-moving glaciers in the warmer, high precipitation sectors of northwest and southeast Greenland. We find that the 100 fastest glaciers (v > 800m/yr) drain 66% of the ice sheet in area, marine-terminating glaciers drain 88% of Greenland, and basal-sliding motion dominates internal deformation over more than 50% of the ice sheet. This view of ice sheet motion provides significant new constraints on ice flow modeling. Copyright 2012 by the American Geophysical Union.

[1]  M. Morlighem,et al.  A mass conservation approach for mapping glacier ice thickness , 2011, Geophysical Research Letters.

[2]  R. Michel,et al.  Flow of Glaciar Moreno, Argentina, from repeat-pass Shuttle Imaging Radar images: comparison of the phase correlation method with radar interferometry , 1999, Journal of Glaciology.

[3]  Karim E. Mattar,et al.  Influence of ionospheric electron density fluctuations on satellite radar interferometry , 2000 .

[4]  B. Smith,et al.  Rates of southeast Greenland ice volume loss from combined ICESat and ASTER observations , 2008 .

[5]  Søren Nørvang Madsen,et al.  Three-dimensional surface velocities of Storstrømmen glacier, Greenland, derived from radar interferometry and ice-sounding radar measurements , 2003 .

[6]  Richard S. Williams,et al.  Satellite image atlas of glaciers of the world , 1988 .

[7]  I. Joughin,et al.  High Geothermal Heat Flow, Basal Melt, and the Origin of Rapid Ice Flow in Central Greenland , 2001, Science.

[8]  W. Krabill,et al.  Penetration depth of interferometric synthetic‐aperture radar signals in snow and ice , 2001, Geophysical Research Letters.

[9]  E. Rignot,et al.  Changes in the Velocity Structure of the Greenland Ice Sheet , 2006, Science.

[10]  P. Heimbach,et al.  Greenland ice-sheet volume sensitivity to basal, surface and initial conditions derived from an adjoint model , 2009, Annals of Glaciology.

[11]  Sivaprasad Gogineni,et al.  A new ice thickness and bed data set for the Greenland ice sheet: 1. Measurement, data reduction, and errors , 2001 .

[12]  Ian M. Howat,et al.  Greenland flow variability from ice-sheet-wide velocity mapping , 2010, Journal of Glaciology.

[13]  J. Ives.  Satellite Image Atlas of Glaciers of the World: Asia, edited by Richard S. Williams, Jr. and Janet G. Ferrigno , 2011 .

[14]  Robin E. Bell,et al.  The role of subglacial water in ice-sheet mass balance , 2008 .

[15]  H. Jiskoot,et al.  Tidewater glacier fluctuations in central East Greenland coastal and fjord regions (1980s–2005) , 2012, Annals of Glaciology.

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

[17]  Philippe Huybrechts,et al.  Melt-induced speed-up of Greenland ice sheet offset by efficient subglacial drainage , 2011, Nature.

[18]  Eric Rignot,et al.  Changes in West Antarctic ice stream dynamics observed with ALOS PALSAR data , 2008 .

[19]  Ian Joughin,et al.  Seasonal Speedup Along the Western Flank of the Greenland Ice Sheet , 2008, Science.

[20]  B. Scheuchl,et al.  Ice Flow of the Antarctic Ice Sheet , 2011, Science.

[21]  Ralf Greve,et al.  Relation of measured basal temperatures and the spatial distribution of the geothermal heat flux for the Greenland ice sheet , 2005, Annals of Glaciology.