Ice flow dynamics and surface meltwater flux at a land-terminating sector of the Greenland ice sheet

Andrew A. W. Fitzpatrick; Alun Hubbard; Ian Joughin; Duncan J. Quincey; Dirk Van As; Andreas Peter Bech Mikkelsen; Samuel H. Doyle; Bent Hasholt; Glenn A. Jones

doi:10.3189/2013JoG12J143

Ice flow dynamics and surface meltwater flux at a land-terminating sector of the Greenland ice sheet

Andrew A. W. Fitzpatrick, Alun Hubbard, Ian Joughin, Duncan J. Quincey, Dirk Van As, Andreas Peter Bech Mikkelsen, Samuel H. Doyle, Bent Hasholt, Glenn A. Jones

LUKKET: Geografi

31 Citationer (Scopus)

Abstract

We present satellite-derived velocity patterns for the two contrasting melt seasons of 2009-10 across Russell Glacier catchment, a western, land-terminating sector of the Greenland ice sheet which encompasses the K(angerlussuaq)-transect. Results highlight great spatial heterogeneity in flow, indicating that structural controls such as bedrock geometry govern ice discharge into individual outlet troughs. Results also reveal strong seasonal flow variability extending 57 km up-glacier to 1200 m elevation, with the largest acceleration (100% over 11 days) occurring within 10 km of the margin coincident with spring melt. By late July 2010, 2 weeks before peak melt and runoff, 48% of the 2400 km(2) catchment had slowed to less than the winter mean. This observation supports the hypothesis that the subglacial hydrological system evolves from an inefficient distributed to an efficient drainage system, regulating flow dynamics. Despite this, the cumulative surface flux over the record melt year of 2010 was still greater compared with the perturbation over the average melt year of 2009. This study supports the proposition that local surface meltwater runoff couples to basal hydrology driving ice-sheet dynamics, and although the effect is nonlinear, our observations indicate that greater meltwater runoff yields increased net flux over this sector of the ice sheet.

Originalsprog	Engelsk
Tidsskrift	Journal of Glaciology
Vol/bind	59
Udgave nummer	216
Sider (fra-til)	687-696
Antal sider	10
ISSN	0022-1430
DOI	https://doi.org/10.3189/2013JoG12J143
Status	Udgivet - aug. 2013

Adgang til dokumentet

10.3189/2013JoG12J143

Citationsformater

@article{cb521805a3d849a5addeab743e9ac86e,

title = "Ice flow dynamics and surface meltwater flux at a land-terminating sector of the Greenland ice sheet",

abstract = "We present satellite-derived velocity patterns for the two contrasting melt seasons of 2009-10 across Russell Glacier catchment, a western, land-terminating sector of the Greenland ice sheet which encompasses the K(angerlussuaq)-transect. Results highlight great spatial heterogeneity in flow, indicating that structural controls such as bedrock geometry govern ice discharge into individual outlet troughs. Results also reveal strong seasonal flow variability extending 57 km up-glacier to 1200 m elevation, with the largest acceleration (100% over 11 days) occurring within 10 km of the margin coincident with spring melt. By late July 2010, 2 weeks before peak melt and runoff, 48% of the 2400 km(2) catchment had slowed to less than the winter mean. This observation supports the hypothesis that the subglacial hydrological system evolves from an inefficient distributed to an efficient drainage system, regulating flow dynamics. Despite this, the cumulative surface flux over the record melt year of 2010 was still greater compared with the perturbation over the average melt year of 2009. This study supports the proposition that local surface meltwater runoff couples to basal hydrology driving ice-sheet dynamics, and although the effect is nonlinear, our observations indicate that greater meltwater runoff yields increased net flux over this sector of the ice sheet.",

author = "Fitzpatrick, {Andrew A. W.} and Alun Hubbard and Ian Joughin and Quincey, {Duncan J.} and {Van As}, Dirk and Mikkelsen, {Andreas Peter Bech} and Doyle, {Samuel H.} and Bent Hasholt and Jones, {Glenn A.}",

year = "2013",

month = aug,

doi = "10.3189/2013JoG12J143",

language = "English",

volume = "59",

pages = "687--696",

journal = "Journal of Glaciology",

issn = "0022-1430",

publisher = "International Glaciological Society",

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TY - JOUR

T1 - Ice flow dynamics and surface meltwater flux at a land-terminating sector of the Greenland ice sheet

AU - Fitzpatrick, Andrew A. W.

AU - Hubbard, Alun

AU - Joughin, Ian

AU - Quincey, Duncan J.

AU - Van As, Dirk

AU - Mikkelsen, Andreas Peter Bech

AU - Doyle, Samuel H.

AU - Hasholt, Bent

AU - Jones, Glenn A.

PY - 2013/8

Y1 - 2013/8

N2 - We present satellite-derived velocity patterns for the two contrasting melt seasons of 2009-10 across Russell Glacier catchment, a western, land-terminating sector of the Greenland ice sheet which encompasses the K(angerlussuaq)-transect. Results highlight great spatial heterogeneity in flow, indicating that structural controls such as bedrock geometry govern ice discharge into individual outlet troughs. Results also reveal strong seasonal flow variability extending 57 km up-glacier to 1200 m elevation, with the largest acceleration (100% over 11 days) occurring within 10 km of the margin coincident with spring melt. By late July 2010, 2 weeks before peak melt and runoff, 48% of the 2400 km(2) catchment had slowed to less than the winter mean. This observation supports the hypothesis that the subglacial hydrological system evolves from an inefficient distributed to an efficient drainage system, regulating flow dynamics. Despite this, the cumulative surface flux over the record melt year of 2010 was still greater compared with the perturbation over the average melt year of 2009. This study supports the proposition that local surface meltwater runoff couples to basal hydrology driving ice-sheet dynamics, and although the effect is nonlinear, our observations indicate that greater meltwater runoff yields increased net flux over this sector of the ice sheet.

AB - We present satellite-derived velocity patterns for the two contrasting melt seasons of 2009-10 across Russell Glacier catchment, a western, land-terminating sector of the Greenland ice sheet which encompasses the K(angerlussuaq)-transect. Results highlight great spatial heterogeneity in flow, indicating that structural controls such as bedrock geometry govern ice discharge into individual outlet troughs. Results also reveal strong seasonal flow variability extending 57 km up-glacier to 1200 m elevation, with the largest acceleration (100% over 11 days) occurring within 10 km of the margin coincident with spring melt. By late July 2010, 2 weeks before peak melt and runoff, 48% of the 2400 km(2) catchment had slowed to less than the winter mean. This observation supports the hypothesis that the subglacial hydrological system evolves from an inefficient distributed to an efficient drainage system, regulating flow dynamics. Despite this, the cumulative surface flux over the record melt year of 2010 was still greater compared with the perturbation over the average melt year of 2009. This study supports the proposition that local surface meltwater runoff couples to basal hydrology driving ice-sheet dynamics, and although the effect is nonlinear, our observations indicate that greater meltwater runoff yields increased net flux over this sector of the ice sheet.

U2 - 10.3189/2013JoG12J143

DO - 10.3189/2013JoG12J143

M3 - Journal article

SN - 0022-1430

VL - 59

SP - 687

EP - 696

JO - Journal of Glaciology

JF - Journal of Glaciology

IS - 216

ER -