Role of discrete water recharge from supraglacial drainage systems in modeling patterns of subglacial conduits in Svalbard glaciers
-
Published:2019-03-04
Issue:3
Volume:13
Page:735-752
-
ISSN:1994-0424
-
Container-title:The Cryosphere
-
language:en
-
Short-container-title:The Cryosphere
Author:
Decaux Léo, Grabiec Mariusz, Ignatiuk DariuszORCID, Jania Jacek
Abstract
Abstract. As the behavior of subglacial water plays a determining role in glacier
dynamics, it requires particular attention, especially in the context of
climate warming, which is increasing ablation and generating greater amounts of
meltwater. On many glaciers, water flowing from the glacier's surface is the
main source of supply to the subglacial drainage system. This system is
largely influenced by the supraglacial drainage system, which collects
meltwater and precipitation and rapidly delivers it to discrete points in the
glacier bed via moulins and crevassed areas, called water input areas (WIAs).
Models of patterns of subglacial conduits mainly based on the hydrological
potential gradient are still regularly performed without taking into account the supraglacial drainage
system. We modeled the pattern of subglacial
channels in two glaciers located in Svalbard, the land-terminating
Werenskioldbreen and the tidewater Hansbreen during the 2015 melt season. We
modeled a spatial and a discrete water recharge in order to compare them.
First, supraglacial catchments were determined for each WIA on a high-resolution digital elevation model using the standard watershed
modeling tool in ArcGIS. Then, interpolated water runoff was calculated for
all the main WIAs. Our model also accounts for several water pressure
conditions. For our two studied glaciers, during the ablation season 2015,
72.5 % of total runoff was provided by meltwater and 27.5 % by
precipitation. Changes in supraglacial drainage on a decadal timescale are
observed in contrast to its nearly stable state on an annual timescale.
Nevertheless, due to the specific nature of those changes, it seems to have a
low impact on the subglacial system. Therefore, our models of subglacial
channel are assumed to be valid for a minimum period of two decades and
depend on changes in the supraglacial drainage system. Results showed that,
for Svalbard tidewater glaciers with large crevassed areas, models of
subglacial channels that assume spatial water recharge may be somewhat
imprecise but are far from being completely incorrect, especially for the
ablation zone. On the other hand, it is important to take discrete water
recharge into account in the case of land-terminating Svalbard glaciers with
limited crevassed areas. In all cases, considering a discrete water recharge
when modeling patterns of theoretical subglacial channels seems to produce
more realistic results according to current knowledge.
Funder
European Space Agency
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
Reference78 articles.
1. Arnold, N., Richards, K., Willis, I., and Sharp, M.: Initial results from a
distributed, physically based model of glacier hydrology, Hydrol. Process.,
12, 191–219, 1998. a 2. Baranowski, S.: The origin of fluted moraine at the fronts of contemporary
glaciers, Geograf. Ann. A, 52, 68–75, 1970. a 3. Baranowski, S.: The subpolar glaciers of Spitsbergen seen against the climate
of this region, Wydawnictwa Uniwersytetu wroclawskiego, Wroclaw University Press, Wroclaw, 1977. a 4. Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T., Palmer, S., and
Wadham, J.: Supraglacial forcing of subglacial drainage in the ablation zone
of the Greenland ice sheet, Geophys. Res. Lett., 38, L08502, https://doi.org/10.1029/2011GL047063, 2011. a 5. Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T., and King, M. A.:
Short-term variability in Greenland Ice Sheet motion forced by time-varying
meltwater drainage: Implications for the relationship between subglacial
drainage system behavior and ice velocity, J. Geophys. Res.-Earth, 117,
F03002, https://doi.org/10.1029/2011JF002220, 2012. a
Cited by
17 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
|
|