Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
doi:10.5194/tcd-9-2053-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
26 Mar 2015
Review status
This discussion paper has been under review for the journal The Cryosphere (TC). The revised manuscript was not accepted.
Active lakes in Antarctica survive on a sedimentary substrate – Part 1: Theory
S. P. Carter, H. A. Fricker, and M. R. Siegfried Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA, USA
Abstract. Over the past decade satellite observations have revealed that active subglacial lake systems are widespread under the Antarctic ice sheet, including the ice streams, yet we have insufficient understanding of the lake-drainage process to incorporate it into ice sheet models. Process models for drainage of ice-dammed lakes based on conventional "R-channels" incised into the base of the ice through melting are unable to reproduce the timing and magnitude of drainage from Antarctic subglacial lakes estimated from satellite altimetry given the low hydraulic gradients along which such lakes drain. We developed a process model in which channels are mechanically eroded into deformable subglacial sediment (till) instead ("T-channel"). When applied to the known lakes of the Whillans/Mercer system, the model successfully reproduced the key characteristics of estimated lake volume changes for the period 2003–2009. If our model is realistic, it implies that most active lakes are shallow and only exist in the presence of saturated sediment, explaining why they are difficult to detect with classical radar methods. It also implies that the lake-drainage process is sensitive to the composition and strength of the underlying till, suggesting that models could be improved with a realistic treatment of sediment – interfacial water exchange.

Citation: Carter, S. P., Fricker, H. A., and Siegfried, M. R.: Active lakes in Antarctica survive on a sedimentary substrate – Part 1: Theory, The Cryosphere Discuss., 9, 2053-2099, doi:10.5194/tcd-9-2053-2015, 2015.
S. P. Carter et al.
S. P. Carter et al.

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Short summary
We develop a model that simulated the observed filling and draining of active subglacial lakes in Antarctica that suggests the may occurs by the erosion of channels into deformable subglacial sediments, that then deform shut as lake level declines. This contrasts with ice dammed alpine lakes which drain by channels incised into ice. If active subglacial lakes require deformable sediments to fill and drain as observed, then classic radar-based methods of lake detection may fail to find them.
We develop a model that simulated the observed filling and draining of active subglacial lakes...
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