The Autumn of break-ups: When Jakobshavn Isbrae lost its floating tongue

Published: Jan 1, 2016 by The PISM Authors

Simulated ice extent and velocity in April (left) and November (right) of 1995.

Simulated ice extent and velocity in April (left) and November (right) of 1995.

   
Title The Autumn of break-ups: When Jakobshavn Isbrae lost its floating tongue
Authors A. Aschwanden, M. Fahnestock, M. Truffer, and R. Motyka
Venue 2015 AGU Fall Meeting

Jakobshavn Isbrae, Greenland’s fastest-flowing outlet glacier, lost its floating tongue in 1995, an event which is often attributed to changes in ocean temperature. This poster and movie show the results of PISM simulations of this event, based on a step increase from 180 m/yr to 225 m/yr in sub-shelf melt rate during 1995 (Motyka et al. 2011). The simulations are started from reasonably-detailed observations of the 1985 state of the outlet glacier. A high-resolution HIRHAM5 reanalysis (Langen et al. 2015) is used for the atmospheric 1989–2011 climate. The results show that general patterns are simulated correctly, with ice speeds which almost double after break-up of the floating tongue. The timing of the break-up is too early and too fast, but these simulations do not include the “ice rumple” (Echelmeyer et al. 1991), which may add stability to the floating tongue.

Share

Latest news

Version 1.2

We are pleased to announce the release of the Parallel Ice Sheet Model (PISM) v1.2.

MPI-M Hamburg, Germany: open postdoc for coupled atmosphere-ocean-ice sheet model

The Max Planck Institute for Meteorology (MPI-M) contributes to the BMBF project “From the Last Interglacial to the Anthropocene: Modeling a Complete Glacial Cycle” (PalMod, www.palmod.de), which aims at simulating the climate from the peak of the last interglacial up to the present using comprehensive Earth System Models. Phase II of this project has an open position Postdoctoral Scientist (W073). The successful candidate will be part of a local team performing and analysing long-term transient simulations covering the last glacial and the transition into the Holocene with an interactively coupled atmosphere-ocean-ice sheet model. Additionally, the candidate will contribute to the continued development of this model. The model system consists of the MPI-Earth system model, the ice sheet model PISM, and the solid-earth model VILMA.

AWI PostDoc: Antarctic Ice Sheets in warming climates

Dr. Lohmann’s group at AWI is seeking a postdoc to work with PISM and the multi-scale Earth system model AWI-ESM. See