FEIT Research Project Database

Melting of Antarctic ice shelves into polar ocean

Project Leader: Bishakhdatta Gayen
Staff: Jimmy Philip, Jason Monty
Student: Mr Mainak Mondal (ANU), Ms Madi Rosevear (Utas)
Collaborators: Dr Ben Galton-Fenzi (Australian Antarctic Division), Assoc Prof Andrew Wells (Oxford University), Dr Craig McConnochie (University of Canterbury)
Sponsors: ARC, AAD
Primary Contact: Bishakhdatta Gayen (bishakhdatta.gayen@unimelb.edu.au)
Keywords: computational fluid dynamics; fluid dynamics
Disciplines: Mechanical Engineering

The melting of ice-sheets in Antarctica and Greenland has played a significant role in global sea level rise, and is predicted to become the largest contribution to sea level rise in future decades. An increased rate of melting of Antarctic glaciers at their grounding line (beyond which the ice is floating on the ocean) has been cited as the probable cause of faster observed glacier motion and the consequent loss of grounded ice from Antarctica. Melting of the ice (which at ambient seawater temperatures near 0°C actually occurs by dissolution of ice into seawater, as it is controlled by salt transport to the ice-water interface) involves molecular diffusion of heat and salt at the ice-water interface coupled to turbulent boundary layer flow. Theoretical work conducted at ANU suggested that the dissolution rate is largely determined by turbulent natural convection against the ice face, driven by salinity-induced density differences. However, parameterised models have instead assumed turbulent transport coefficients that are solely based on ambient geostrophic current velocities. We are investigating the physical processes that control these ice-ocean interactions and the resulting circulation at basin scale.

Group research focuses on:

  • Numerical models: Melting (or dissolving) of the ice involves complex turbulent boundary layer flow, which is largely driven by convection due to temperature and salinity differences. Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) are excellent tools for obtaining solutions under both laboratory and ocean conditions that can be compared with experimental data and, eventually, ocean observations.
  • Laboratory models: The laboratory experiments will be conducted in our temperature controlled cold room. The cold room allows us to conduct experiments at conditions that are close to what would be found near actual Antarctic ice shelves. The laboratory experiments let us measure some of the fluid properties a lot closer to the ice surface than a lot of the field studies can as well as in a more controlled environment. They also provide a real data set that can be used to confirm and test theoretical or numerical results. We have currently been focused on the effect of ambient temperature and stratification on the melt rate but expect to add external flow and geometry in the future.

Further information: https://sites.google.com/site/bishakhdattagayen/research/ice-melting-under-seawater

Overview of problem