TY - JOUR
T1 - Rapidly changing subglacial hydrological pathways at a tidewater glacier revealed through simultaneous observations of water pressure, supraglacial lakes, meltwater plumes and surface velocities
AU - How, Penelope
AU - Benn, Douglas I.
AU - Hulton, Nicholas R.J.
AU - Hubbard, Bryn
AU - Luckman, Adrian
AU - Sevestre, Heïdi
AU - van Pelt, Ward J.J.
AU - Lindbäck, Katrin
AU - Kohler, Jack
AU - Boot, Wim
N1 - Funding Information:
Acknowledgements. This work was funded by the Conoco Phillips-Lundin Northern Area Program through the CRIOS project (Calving Rates and Impact On Sea level, http://www.researchinsvalbard.no/project/7037). Penelope How is supported by a NERC PhD studentship. TerraSAR-X data were provided by DLR (project OCE1503). This work would not have been possible without the logistical support provided by Airlift AS, the Norwegian Polar Institute Sverdrup Research Station in Ny Ålesund, and the University Centre in Svalbard (UNIS) Tech and Logistics team. We greatly acknowledge Alex Hart and the GeoSciences Mechanical Workshop at the University of Edinburgh for manufacturing the time-lapse camera enclosures that were used in this study. Bryn Hubbard acknowledges capital equipment support from HEFCW/Aberystwyth University. We would also like to thank Silje Smith-Johnsen for her assistance in the deployment of the time-lapse cameras, Fiona Clubb for her guidance on data visualisation, Donald Slater for useful comments and feedback on this paper, Andreas Vieli as the nominated editor of this paper, and the three appointed reviewers who consisted of Shin Sugiyama and two anonymous reviewers.
Publisher Copyright:
© 2017 Author.
PY - 2017/11/21
Y1 - 2017/11/21
N2 - Subglacial hydrological processes at tidewater glaciers remain poorly understood due to the difficulty in obtaining direct measurements and lack of empirical verification for modelling approaches. Here, we investigate the subglacial hydrology of Kronebreen, a fast-flowing tidewater glacier in Svalbard during the 2014 melt season. We combine observations of borehole water pressure, supraglacial lake drainage, surface velocities and plume activity with modelled run-off and water routing to develop a conceptual model that thoroughly encapsulates subglacial drainage at a tidewater glacier. Simultaneous measurements suggest that an early-season episode of subglacial flushing took place during our observation period, and a stable efficient drainage system effectively transported subglacial water through the northern region of the glacier tongue. Drainage pathways through the central and southern regions of the glacier tongue were disrupted throughout the following melt season. Periodic plume activity at the terminus appears to be a signal for modulated subglacial pulsing, i.e. an internally driven storage and release of subglacial meltwater that operates independently of marine influences. This storage is a key control on ice flow in the 2014 melt season. Evidence from this work and previous studies strongly suggests that long-term changes in ice flow at Kronebreen are controlled by the location of efficient/inefficient drainage and the position of regions where water is stored and released.
AB - Subglacial hydrological processes at tidewater glaciers remain poorly understood due to the difficulty in obtaining direct measurements and lack of empirical verification for modelling approaches. Here, we investigate the subglacial hydrology of Kronebreen, a fast-flowing tidewater glacier in Svalbard during the 2014 melt season. We combine observations of borehole water pressure, supraglacial lake drainage, surface velocities and plume activity with modelled run-off and water routing to develop a conceptual model that thoroughly encapsulates subglacial drainage at a tidewater glacier. Simultaneous measurements suggest that an early-season episode of subglacial flushing took place during our observation period, and a stable efficient drainage system effectively transported subglacial water through the northern region of the glacier tongue. Drainage pathways through the central and southern regions of the glacier tongue were disrupted throughout the following melt season. Periodic plume activity at the terminus appears to be a signal for modulated subglacial pulsing, i.e. an internally driven storage and release of subglacial meltwater that operates independently of marine influences. This storage is a key control on ice flow in the 2014 melt season. Evidence from this work and previous studies strongly suggests that long-term changes in ice flow at Kronebreen are controlled by the location of efficient/inefficient drainage and the position of regions where water is stored and released.
UR - http://www.scopus.com/inward/record.url?scp=85035069558&partnerID=8YFLogxK
U2 - 10.5194/tc-11-2691-2017
DO - 10.5194/tc-11-2691-2017
M3 - Article
AN - SCOPUS:85035069558
SN - 1994-0416
VL - 11
SP - 2691
EP - 2710
JO - Cryosphere
JF - Cryosphere
IS - 6
ER -