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Drainage networks, lakes and water fluxes beneath the Antarctic ice sheet


Willis, Ian C; Pope, Ed L; Leysinger Vieli, Gwendolyn; Arnold, Neil S; Long, Sylvan (2016). Drainage networks, lakes and water fluxes beneath the Antarctic ice sheet. Annals of Glaciology, 57(72):96-108.

Abstract

Antarctica Bedmap2 datasets are used to calculate subglacial hydraulic potential and the area, depth and volume of hydraulic potential sinks. There are over 32 000 contiguous sinks, which can be thought of as predicted lakes. Patterns of subglacial melt are modelled with a balanced ice flux flow model, and water fluxes are cumulated along predicted flow pathways to quantify steady-state fluxes from the main basin outlets and from known subglacial lakes. The total flux from the continent is ~21 km3 a−1. Byrd Glacier has the greatest basin flux of ~2.7 km3 a−1. Fluxes from subglacial lakes range from ~1 × 10−4 to ~1.5 km3 a−1. Lake turnover times are calculated from their volumes and fluxes, and have median values of ~100 a for known ‘active’ lakes and ~500 a for other lakes. Recurrence intervals of a 0.25 km3 flood range from ~2 months to ~2000 a (median ≈130 a) for known ‘active’ lakes and from ~2 to ~2400 a (median ≈ 360 a) for other lakes. Thus, several lakes that have recently been observed to fill and drain may not do so again for many centuries; and several lakes that have not, so far, been observed to fill and drain have the potential to do so, even at annual to decadal timescales.

Abstract

Antarctica Bedmap2 datasets are used to calculate subglacial hydraulic potential and the area, depth and volume of hydraulic potential sinks. There are over 32 000 contiguous sinks, which can be thought of as predicted lakes. Patterns of subglacial melt are modelled with a balanced ice flux flow model, and water fluxes are cumulated along predicted flow pathways to quantify steady-state fluxes from the main basin outlets and from known subglacial lakes. The total flux from the continent is ~21 km3 a−1. Byrd Glacier has the greatest basin flux of ~2.7 km3 a−1. Fluxes from subglacial lakes range from ~1 × 10−4 to ~1.5 km3 a−1. Lake turnover times are calculated from their volumes and fluxes, and have median values of ~100 a for known ‘active’ lakes and ~500 a for other lakes. Recurrence intervals of a 0.25 km3 flood range from ~2 months to ~2000 a (median ≈130 a) for known ‘active’ lakes and from ~2 to ~2400 a (median ≈ 360 a) for other lakes. Thus, several lakes that have recently been observed to fill and drain may not do so again for many centuries; and several lakes that have not, so far, been observed to fill and drain have the potential to do so, even at annual to decadal timescales.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Date:2016
Deposited On:02 Feb 2017 10:26
Last Modified:02 Feb 2017 10:27
Publisher:International Glaciological Society
ISSN:0260-3055
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1017/aog.2016.15

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