Publication Date:
2019-07-17
Description:
Disintegration events in ice shelves have been the subject of extensive investigations in the past years, however
comprehensive explanations applicable to a majority of events are still missing. A popular assumption made by
Scambos et al. (2000) [1] links disintegration events to a general thinning of the ice shelf in conjunction with
growing melt-water ponds leading to hydro fractures. This explanation seems reasonable for break-up events that
happened in Antarctic summers.
Large parts of the Wilkins Ice Shelf, however broke-up in fall and winter periods. Therefore, the aim of the present
study is to analyse the possibility of frost wedging of water filled surface crevasses in an ice shelf as a source of
break-up events.
Configurational forces are used to assess crack criticality. The simulations are performed on a 2-dimensional
single crack with a mode-I type load, body forces and additional crack-face pressure due to freezing of the water.
Depth-dependent density profiles are considered. The relevant parameters, Young’s modulus, Poisson’s ratio and
external loading are obtained from literature, remote sensing data analysis and modelling of the ice dynamics. The
investigation is performed using the finite element software COMSOL. The simulations show that in comparison
to water filled crevasses without ice, thin layers of frozen water may lead to a decreasing criticality at the crack tip
as long as the ice ‘bridge’ is allowed to take tensile loads. An increasing crack criticality can be seen for thicker
layers of ice. The results are compared to findings from previous finite element analyses of dry and water filled
cracks as presented in Plate et al. (2012) [2].
[1] Scambos, T., Hulbe, C., Fahnestock, M., & Bohlander, J. (2000). The link between climate warming
and break-up of ice shelves in the Antarctic Peninsula. Journal of Glaciology, 46(154), 516–530.
[2] Plate, C., Müller, R., Humbert, A., & Gross, D. (2012). Evaluation of the criticality of cracks in ice
shelves using finite element simulations. The Cryosphere, 6(5), 973–984.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Conference
,
notRev
Format:
application/pdf
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