Project Details
Projekt
The influence of fracture-induced calving on Antarctica's contribution to future sea-level change
Applicant
Professor Dr. Anders Levermann
Subject Area
Oceanography
Term
from 2014 to 2017
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 257497716
The Antarctic ice sheet is drained to about 90% through the surrounding ice shelves and water-terminating glaciers. Iceberg calving is a major mechanism of ice loss and is preconditioned by fractures. Usually fractures form far upstream in accelerating ice streams and along the shear margins of the ice shelves and are transported in bands with the ice towards the calving front. We have already developed a model approach that accounts for the formation, growth and transport of fractures in ice shelves and compared the results to visible satellite observation. We further introduced a macroscopic coupling of ice flow and fracture processes, which represents a potentially self-amplifying feedback mechanism and provides explanations for several observed features of ice flow. Based on the previous work we want to expand the fracture-density approach and derive a fracture-coupled calving parameterization. By using new insights from field data and airborne observations, provided by Christine Wesche (AWI), we would like to quantify expected average size and frequency of iceberg release. We will account explicitly for the vertical growth of cracks and horizontal propagation of rifts before getting detached as icebergs. We will apply this enhanced calving parameterization in a simulation of the Antarctic ice sheet for the period since the Last Glacial Maximum (LGM). In collaboration with Michael Weber and Rupert Gladstone we would like to study the transport of simulated icebergs with the coastal current to compare the computed iceberg fluxes with paleo sediment data. This model exercise would provide a holistic understanding of fast changes in the past and possible dynamic responses in a changing future climate.
DFG Programme
Infrastructure Priority Programmes
