Bumps Ahead: An Investigation into the Calculation and Evolution of Roughness in Ice Shelves
Abstract
Stability of the Antarctic Ice Sheet is linked to ice shelves and their collapse could trigger widespread drawdown and retreat of marine based portions of the ice sheet. However, little is known about the processes that control the stability of ice shelves. Recent observations show that the bottom of ice shelves have extensive topography across a spectrum of wavelengths. Current literature speculates that these features are the direct result of basal crevasse formation and melt channels. Here, we use ground penetrating radar from Operation IceBridge Data to quantify roughness beneath ice shelves using a continuous wavelet transform. Our preliminary results for Pine Island, Thwaites and the Larsen C Ice Shelves show large variability in the roughness across ice shelves, but roughness is concentrated across distinct spectral bands. These bands exist in a specific wavelength range depending on the features present and have lengths defined by the real-space size of the features. We find topography falls into a spectrum with short wavelength features (ones less than 1-2 km in length) predominantly associated with crevasses and large wavelength features (ones ranging from 2km up to 10km) coinciding with melt channels. Moreover, features that we identify as crevasses are correlated with high strain rates where as those that we detect as melt channels do not tend to relate with strain rate. In testing the temporal evolution of basal features with a full Stokes model, we find that in simulations up to 10 years there is very little smoothing of the features. This stands in contrast to observational data of repeat flight lines taken at different years in which there is substantial change.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C53C1359W
- Keywords:
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- 0728 Ice shelves;
- CRYOSPHERE;
- 0774 Dynamics;
- CRYOSPHERE;
- 0776 Glaciology;
- CRYOSPHERE;
- 0798 Modeling;
- CRYOSPHERE