Rapid Changes in Ice Discharge from Greenland Outlet Glaciers

Using satellite-derived surface elevation and velocity data, we found major short-term variations in recent ice discharge and mass loss at two of Greenland's largest outlet glaciers. Their combined rate of mass loss doubled in less than a year in 2004 and then decreased in 2006 to near the previous rates, likely as a result of fast re-equilibration of calving-front geometry after retreat. Total mass loss is a fraction of concurrent gravity-derived estimates, pointing to an alternative source of loss and the need for high-resolution observations of outlet dynamics and glacier geometry for sea-level rise predictions.

[1]  Barclay Kamb,et al.  Stress-Gradient Coupling in Glacier Flow: I. Longitudinal Averaging of the Influence of Ice Thickness and Surface Slope , 1986, Journal of Glaciology.

[2]  Mark F. Meier,et al.  Fast tidewater glaciers , 1987 .

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

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

[5]  C. J. van der Veen,et al.  Fundamentals of glacier dynamics , 1999 .

[6]  Eric Rignot,et al.  Substantial thinning of a major east Greenland outlet glacier , 2000 .

[7]  J. Legarsky,et al.  Coherent radar ice thickness measurements over the Greenland ice sheet , 2001 .

[8]  Ian Joughin,et al.  Ice-sheet velocity mapping: a combined interferometric and speckle-tracking approach , 2002, Annals of Glaciology.

[9]  Konrad Steffen,et al.  Investigation of surface melting and dynamic thinning on Jakobshavn Isbrae, Greenland , 2003 .

[10]  Robert N. Swift,et al.  Greenland Ice Sheet: Increased coastal thinning , 2004 .

[11]  R. Thomas,et al.  Force-perturbation analysis of recent thinning and acceleration of Jakobshavn Isbræ, Greenland , 2004, Journal of Glaciology.

[12]  T. Scambos,et al.  Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment, Antarctica , 2004 .

[13]  A. Vieli,et al.  Recent dramatic thinning of largest West Antarctic ice stream triggered by oceans , 2004 .

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

[15]  Ian M. Howat,et al.  Rapid retreat and acceleration of Helheim Glacier, east Greenland , 2005 .

[16]  B. T. San,et al.  Digital elevation model (DEM) generation and accuracy assessment from ASTER stereo data , 2005 .

[17]  J. Wahr,et al.  Acceleration of Greenland ice mass loss in spring 2004 , 2006, Nature.

[18]  Greenland Rumbles Louder as Glaciers Accelerate , 2006, Science.

[19]  Tavi Murray,et al.  Rapid and synchronous ice‐dynamic changes in East Greenland , 2006 .

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

[21]  R. Nerem,et al.  Recent Greenland Ice Mass Loss by Drainage System from Satellite Gravity Observations , 2006, Science.

[22]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.