Modeling the instantaneous response of glaciers after the collapse of the Larsen B Ice Shelf

Abstract

Following the disintegration of the Larsen B Ice Shelf, Antarctic Peninsula, in 2002, regular surveillance of its ∼20 tributary glaciers has revealed a response which is varied and complex in both space and time. The major outlets have accelerated and thinned, smaller glaciers have shown little or no change, and glaciers flowing into the remnant Scar Inlet Ice Shelf have responded with delay. In this study we present the first areawide numerical analysis of glacier dynamics before and immediately after the collapse of the ice shelf, combining new data sets and a state‐of‐the‐art numerical ice flow model. We simulate the loss of buttressing at the grounding line and find a good qualitative agreement between modeled changes in glacier flow and observations. Through this study, we seek to improve confidence in our numerical models and their ability to capture the complex mechanical coupling between floating ice shelves and grounded ice.

Recent rift formation and impact on the structural integrity of the Brunt Ice Shelf, East Antarctica

“…The mean residual between observed and modelled surface speeds for the BIS was found to be 1.8±9.6 m/yr or 0.2±2.1%, which is a significant improvement over De Rydt et al (2015) and Gudmundsson et al 30 (2017) due to recent improvements in the inversion procedure in Úa, and Larour et al (2014), who found a best match for the BIS of around 10%. The principle stress rosettes in Figure 8a ice shelf and the bedrock at the MIR, and has resulted in the radially-outward growth of the HC, perpendicular to the tensile stresses.…”

Widespread movement of meltwater onto and across Antarctic ice shelves

“…4d), increasing delivery of water to ice shelves. If water can access areas vulnerable to hydraulically driven fracture, ice-shelves can collapse, which accelerates upstream thinning 4 . How different parts of Antarctica's surface drainage system will respond to increased surface melting 6 will vary.…”

“…Accumulation of locally derived meltwater has triggered ice-shelf collapse in Antarctica's warmest regions 4 . Large-scale transport of meltwater could accelerate mass loss elsewhere on the continent.…”

Recent rift formation and impact on the structural integrity of the Brunt Ice Shelf, East Antarctica

“…The mean residual and standard deviation between observed and modelled surface speeds for the BIS was found to be 1.4 (16.6) m yr −1 or 0.2 (4) %, which is a significant improvement over De Rydt et al (2015) and Gudmundsson et al (2017) due to recent improvements in the inversion procedure in Úa and over Larour et al (2014), who found a best match for the BIS of around 10 %. A priori, the calculated fracture trajectories depend on the amount of regularization (λ AGlen ) and the model resolution.…”