Coupled modelling of subglacial hydrology and calving-front melting at Store Glacier, West Greenland
<p>We investigate the subglacial hydrology of Store Glacier in West Greenland, using the open-source, full-Stokes model Elmer/Ice in a novel 3D application that includes a distributed water sheet, as well as discrete channelised drainage, and a 1D model to simulate submarine plumes at the calv...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-03-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/14/905/2020/tc-14-905-2020.pdf |
| Summary: | <p>We investigate the subglacial hydrology of Store Glacier in West Greenland,
using the open-source, full-Stokes model Elmer/Ice in a novel 3D application
that includes a distributed water sheet, as well as discrete channelised
drainage, and a 1D model to simulate submarine plumes at the calving front.
At first, we produce a baseline winter scenario with no surface meltwater.
We then investigate the hydrological system during summer, focussing
specifically on 2012 and 2017, which provide examples of high and low
surface-meltwater inputs, respectively. We show that the common assumption
of zero winter freshwater flux is invalid, and we find channels over 1 m<span class="inline-formula"><sup>2</sup></span>
in area occurring up to 5 km inland in winter. We also find that the production of
water from friction and geothermal heat is sufficiently high to drive
year-round plume activity, with ice-front melting averaging 0.15 m d<span class="inline-formula"><sup>−1</sup></span>.
When the model is forced with seasonally averaged surface melt from summer,
we show a hydrological system with significant distributed sheet activity
extending 65 and 45 km inland in 2012 and 2017, respectively; while
channels with a cross-sectional area higher than 1 m<span class="inline-formula"><sup>2</sup></span> form as far as 55 and 30 km inland. Using daily values for the surface melt as forcing, we
find only a weak relationship between the input of surface meltwater and the
intensity of plume melting at the calving front, whereas there is a strong
correlation between surface-meltwater peaks and basal water pressures. The
former shows that storage of water on multiple timescales within the
subglacial drainage system plays an important role in modulating subglacial
discharge. The latter shows that high melt inputs can drive high basal water
pressures even when the channelised network grows larger. This has
implications for the future velocity and mass loss of Store Glacier, and the
consequent sea-level rise, in a warming world.</p> |
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| ISSN: | 1994-0416 1994-0424 |