Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt
By T. Dunse, T. Schellenberger, J. Hagen, Andreas Kääb, Thomas V. Schuler, C. Reijmer. 2015
163 citations recorded by the source corpus.
Abstract. Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the polar regions. Here we present continuous GPS measurements and satellite synthetic-aperture-radar-based velocity maps from Basin-3, the largest drainage basin of the Austfonna ice cap, Svalbard. Our observations demonstrate strong links between surface-melt and multiannual ice-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant ice regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of Basin-3. The resulting iceberg discharge of 4.2±1.6 Gt a−1 over the period April 2012 to May 2013 triples the calving loss from the entire ice cap. With the seawater displacement by the terminus advance accounted for, the related sea-level rise contribution amounts to 7.2±2.6 Gt a−1. This rate matches the annual ice-mass loss from the entire Svalbard archipelago over the period 2003–2008, highlighting the importance of dynamic mass loss for glacier mass balance and sea-level rise. The active role of surface melt, i.e. external forcing, contrasts with previous views of glacier surges as purely internal dynamic instabilities. Given sustained climatic warming and rising significance of surface melt, we propose a potential impact of the hydro-thermodynamic feedback on the future stability of ice-sheet regions, namely at the presence of a cold-based marginal ice plug that restricts fast drainage of inland ice. The possibility of large-scale dynamic instabilities such as the partial disintegration of ice sheets is acknowledged but not quantified in global projections of sea-level rise.
Subfields: Atmospheric Science, Pulmonary and Respiratory Medicine
View Paper: https://www.semanticscholar.org/paper/a62f5154327db6ebc428cc2dcef81d9a1842685c
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In Atmospheric Science
- S. Swenson
- Isabella Velicogna
- Enrico Ciracì
- John M. Wahr
- Byron D. Tapley
- Srinivas V. Bettadpur
- Anny Cazenave
- Clinton P. Conrad
In Pulmonary and Respiratory Medicine
Citations in the corpus
- Continuity of the Mass Loss of the World's Glaciers and Ice Caps From the GRACE and GRACE Follow‐On Missions (2020, result): “Our GIC estimates for 2003–2009 agree with Gardner et al. (2013) (Figure S1 and Table S2), except for the Southern Andes where we use an updated inventory. Our errors for HMA are also two times smaller because of improved hydrological corrections (Table S2). Our mass loss estimates are higher than R”