Abstract
Abstract. Nearly all meltwater from glaciers and ice sheets is routed
englacially through moulins. Therefore, the geometry and evolution of
moulins has the potential to influence subglacial water pressure variations,
ice motion, and the runoff hydrograph delivered to the ocean. We develop the
Moulin Shape (MouSh) model, a time-evolving model of moulin geometry. MouSh
models ice deformation around a moulin using both viscous and elastic
rheologies and melting within the moulin through heat dissipation from
turbulent water flow, both above and below the water line. We force MouSh
with idealized and realistic surface melt inputs. Our results show that,
under realistic surface melt inputs, variations in surface melt change the
geometry of a moulin by approximately 10 % daily and over 100 %
seasonally. These size variations cause observable differences in moulin
water storage capacity and moulin water levels compared to a static,
cylindrical moulin. Our results suggest that moulins are important storage
reservoirs for meltwater, with storage capacity and water levels varying
over multiple timescales. Implementing realistic moulin geometry within
subglacial hydrologic models may therefore improve the representation of
subglacial pressures, especially over seasonal periods or in regions where
overburden pressures are high.
Funder
National Aeronautics and Space Administration
Subject
Earth-Surface Processes,Water Science and Technology
Reference105 articles.
1. Aadnøy, B. S.: A complete elastic model for fluid-induced and in-situ
generated stresses with the presence of a borehole, Energy Sources, 9,
239–259, 1987.
2. Alley, R. B.: Flow-law hypotheses for ice-sheet modeling, J. Glaciol., 38,
245–256, https://doi.org/10.3189/S0022143000003658, 1992.
3. Alley, R. B., Dupont, T. K., Parizek, B. R., and Anandakrishnan, S.: Access
of surface meltwater to beds of sub-freezing glaciers: preliminary insights,
Ann. Glaciol., 40, 8–14, https://doi.org/10.3189/172756405781813483, 2005.
4. Amadei, B.: Rock Anisotropy and the Theory of Stress Measurements,
Springer Berlin, Heidelberg, Germany, ISBN 978-3-540-12388-0, 1983.
5. Andrews, L. C., Catania, G. A., Hoffman, M. J., Gulley, J. D., Lüthi, M.
P., Ryser, C., Hawley, R. L., and Neumann, T. A.: Direct observations of
evolving subglacial drainage beneath the Greenland Ice Sheet, Nature,
514, 80–83, https://doi.org/10.1038/nature13796, 2014.
Cited by
7 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献