Modeling 5 years of subglacial lake activity in the MacAyeal Ice Stream (Antarctica) catchment through assimilation of ICESat laser altimetry

Subglacial lakes beneath Antarctica’s fast-moving ice streams are known to undergo ∼1 km3 volume changes on annual timescales. Focusing on the MacAyeal Ice Stream (MacIS) lake system, we create a simple model for the response of subglacial water distribution to lake discharge events through assimila...

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Veröffentlicht in:Journal of glaciology Jg. 57; H. 206; S. 1098 - 1112
Hauptverfasser: Carter, Sasha P., Fricker, Helen A., Blankenship, Donald D., Johnson, Jesse V., Lipscomb, William H., Price, Stephen F., Young, Duncan A.
Format: Journal Article
Sprache:Englisch
Veröffentlicht: Cambridge, UK Cambridge University Press 01.01.2011
International Glaciological Society
Schlagworte:
Earth, ocean, space
Exact sciences and technology
External geophysics
Freshwater
Snow. Ice. Glaciers
polar regions
West Antarctica
Antarctica
ICESat satellite
ice sheets
Subglacial lake
Space remote sensing
Satellite observation
Polar region
Modeling
Ice stream
Laser altimetry
ISSN:0022-1430, 1727-5652
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Zusammenfassung:Subglacial lakes beneath Antarctica’s fast-moving ice streams are known to undergo ∼1 km3 volume changes on annual timescales. Focusing on the MacAyeal Ice Stream (MacIS) lake system, we create a simple model for the response of subglacial water distribution to lake discharge events through assimilation of lake volume changes estimated from Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry. We construct a steady-state water transport model in which known subglacial lakes are treated as either sinks or sources depending on the ICESat-derived filling or draining rates. The modeled volume change rates of five large subglacial lakes in the downstream portion of MacIS are shown to be consistent with observed filling rates if the dynamics of all upstream lakes are considered. However, the variable filling rate of the northernmost lake suggests the presence of an undetected lake of similar size upstream. Overall, we show that, for this fast-flowing ice stream, most subglacial lakes receive >90% of their water from distant distributed sources throughout the catchment, and we confirm that water is transported from regions of net basal melt to regions of net basal freezing. Our study provides a geophysically based means of validating subglacial water models in Antarctica and is a potential way to parameterize subglacial lake discharge events in large-scale ice-sheet models where adequate data are available.
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ISSN:0022-1430
1727-5652
DOI:10.3189/002214311798843421