Mechanical effect of mélange-induced buttressing on embayment-terminating glacier dynamics
D. Seneca Lindsey and T. K. Dupont
Department of Earth System Science, The University of California Irvine, 3200 Croul Hall, Irvine, CA 92697-3100, USA
Received: 31 Aug 2012 – Accepted for review: 03 Sep 2012 – Discussion started: 26 Sep 2012
Abstract. Embayment terminating glaciers interact dynamically with seasonal sea ice and icebergs, a mixture we refer to as mélange. For certain glaciers, mélange prevents calved bergs from rotating away from the front, thus allowing the ice front to advance into the embayment. Here we demonstrate that mélange can, if rigid enough, provide sufficient buttressing to reduce the calving rate, while leaving the ice-front velocity largely unaffected. The net result is additional ice-front advance.
Observations indicate a seasonal advance/retreat cycle has occurred at Jakobshavn Isbræ since the 1950s. We model an idealized Jakobshavn Isbræ-like scenario and find that mélange may be responsible for a seasonal ice-front advance of up to 0.6 km. These results come from a model that incorporates mélange into the interior of the domain, includes relevant stresses, and models drag via a kinematic boundary condition. A weakening or loss of mélange due to increasing temperatures would lead to further mass loss from glaciers such as Jakobshavn Isbræ.
Seneca Lindsey, D. and Dupont, T. K.: Mechanical effect of mélange-induced buttressing on embayment-terminating glacier dynamics, The Cryosphere Discuss., 6, 4123-4136, doi:10.5194/tcd-6-4123-2012, 2012.