Title:	AISS-mélange. Antarctic ice sheet stability: ocean-ice-mélange model to reduce uncertainties
DNr:	SNIC 2022/5-439
Project Type:	SNIC Medium Compute
Principal Investigator:	Lars Arneborg <lars.arneborg@smhi.se>
Affiliation:	SMHI
Duration:	2022-11-01 – 2023-11-01
Classification:	10503 10509 10599
Homepage:	https://thwaitesglacier.org/people/dorothee-vallot
Keywords:

Abstract

The purpose of this project is to better understand ice-ocean processes involved in the potential collapse of the Antarctic Ice Sheet to help reducing uncertainties in sea level rise projections. Thwaites glacier, Amundsen Sea, West Antarctica, already retreating and doomed to collapse, is used as an analogue to the future of the ice sheet. The glacier tongue is composed of broken pieces of icebergs grounded on the sea floor on a shallow zone. Its buttressing effect reduces the ice speed but is weakened by ocean melting. The aim of the project is to understand the processes involved at the ocean-ice interface of this ‘mélange tongue’ by coupling a continuum ice flow model, a particle model and an ocean model. The novelty of this project is to consider the broken state of an ice tongue as a potential future evolution of ice shelves in Antarctica and model its interaction with the ocean. To understand the system as a whole, a coupling between the ice and the ocean is necessary. However, traditional marine ice sheet models use continuum physics to describe ice flow but the present conditions of the fractured ice tongue demand to model the ice as a granular material. For that reason, a discrete particle model is a better candidate. The overarching goal is to understand the role of the ’mélange tongue’ versus sub-shelf melting by ocean forcing in ice sheet stability by coupling a continuum model to simulate the ice flow, a particle model to simulate the breaking of ice and ’mélange tongue’ processes and a primitive equation ocean model. The key targets are grounding points between the mélange and the sea floor, where melting might well be accelerated due to topographic constrictions.