October 27, 2016
September 6, 2016
Highlights •NASA/JPL's Ice Sheet System Model ported to the Amazon EC2 Cloud. •First ever application of Cloud computing to modeling of polar ice flow. •Combining ISSM high-end and EC2 Cloud computing accelerates delivery of projections. •Cloud elasticity eliminates batch queuing time in uncertainty quantification runs. •Demonstrates feasibility of uncertainty quantification in sea-level projections.
June 23, 2016
The 2016 ISSM workshop took place on June 21-23, 2016 at the Scripps Institution for Oceanography, in collaboration with the Jet Propulsion Laboratory and the University of California, Irvine. During the three-day workshop, participants learned about ISSM, the newest capabilities, and performed hands-on tutorials. Thank you all for your participation!
March 18, 2016
We present a numerically accurate, computationally efficient, (km-scale) high-resolution model for gravitationally consistent relative sea level that, unlike contemporary state-of-the-art models, operates efficiently on an unstructured mesh. The model is useful for earth system modeling and space geodesy. A straightforward and computationally less burdensome coupling to a dynamical ice-sheet model, for example, allows a refined and realistic simulation of fast-flowing outlet glaciers.
March 18, 2016
Glacier-front dynamics is an important control on Greenland's ice mass balance. Warmer ocean waters trigger ice-front retreats of marine-terminating glaciers, and the corresponding loss in resistive stress leads to glacier acceleration and thinning. Here we present an approach to quantify the sensitivity and vulnerability of marine-terminating glaciers to ocean-induced melt. We develop a plan view model of Store Gletscher that includes a level set-based moving boundary capability, a parameterized ocean-induced melt, and a calving law with complete and precise land and fjord topographies to model the response of the glacier to increased melt. We find that the glacier is stabilized by a sill at its terminus. The glacier is dislodged from the sill when ocean-induced melt quadruples, at which point the glacier retreats irreversibly for 27 km into a reverse bed. The model suggests that ice-ocean interactions are the triggering mechanism of glacier retreat, but the bed controls its magnitude.
March 3, 2016
We implemented a level-set method in the ice sheet system model. This method allows us to dynamically evolve a calving front subject to user-defined calving rates. We apply the method to Jakobshavn Isbræ, West Greenland, and study its response to calving rate perturbations. We find its behaviour strongly dependent on the calving rate, which was to be expected. Both reduced basal drag and rheological shear margin weakening sustain the acceleration of this dynamic outlet glacier.