Evolution of Greenland Marine-Terminating Glacier Dynamics Throughout a 30-Year Period of Stability and Retreat
Abstract
Changes in mass resulting from evolving glacier dynamics are one of the largest contributors to recent mass loss from the Greenland Ice Sheet, yet individual glacier dynamic losses are highly variable even within a region. We examine the dynamics of the lower trunks of a group of glaciers in Greenland over a 30-year period where many, but not all, have gone from stable to retreating. Previous analysis of glacier dynamics has focused on individual time periods or single glaciers. By studying the evolving dynamic changes of several glaciers over an extended time period that includes significant mass loss, the controlling processes of dynamic mass loss are elucidated. A focus on these changes can validate previous theoretical work and provide better constrained predictions for future dynamic mass loss.
Changes in the dynamics of a glacier are understood through the balance of forces that are at play. Dynamic changes include variation in stress, strain, and velocity, which we calculate for individual glaciers from a variety of new, freely available, data products for the years from 1985 to 2015. Calculations of a force balance require accurate DEMs at each timestep that stresses are calculated, however DEMs are not available throughout much of the time frame analyzed. We fill in the temporally patchy DEM data with pseudo-DEMs constructed from ATM data. The time-series of force balances allows us to examine the evolution of stresses during irreversible tidewater glacier retreat, and to compare this evolution across glacier catchments with differing dynamic responses to climate forcing. After calculating force balances between 1985 and 2015, we compare our findings to theoretical predictions for the transient evolution of stresses, and examine the accuracy of predictions for terminus stability.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C41C1476C
- Keywords:
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- 0758 Remote sensing;
- CRYOSPHERE;
- 0774 Dynamics;
- CRYOSPHERE;
- 0798 Modeling;
- CRYOSPHERE