Drift, dispersion and deformation of sea ice: A physical perspective

Speaker: 
Jérôme Weiss
Affiliation: 
CNRS - Laboratoire de Glaciologie et Géophysique de l'Environnement (Grenoble, France)
Seminar Date: 
11. April 2013 - 12:30 - 13:00
Location: 
Lecture room, Ground Floor, NERSC

In this presentation, I will discuss the properties of sea ice motion: sea ice velocity fields and their gradients, i.e. strain-rate fields, mainly from lagrangian passive tracers (buoy trajectories). I will show that the sea ice velocity field can be decomposed into a mean field (i.e. a general circulation) + stochastic fluctuations. The statistical properties of these fluctuations cannot be explained by the turbulent properties of the forcing field (the winds), but also result from the strongly non-linear response of sea ice. This is confirmed by an analysis of strain-rate fields, which exhibit extreme spatial heterogeneity coupled to a strong intermittency, i.e. mimic the behavior of the brittle upper Earth's crust. This brittle behavior should constrain future modeling developments of sea ice rheology.