Sea ice talk: Floe-scale ridging in discrete element models for sea ice

Below is my recorded talk for an upcoming workshop on modeling the granular nature of sea ice. The workshop is online, and will take place in the week of June 7th, 2021. Full abstract:

Floe-scale ridging in discrete element models for sea ice

Anders Damsgaard(1,2), Olga V. Sergienko(1), Alistair Adcroft(1)

1: Program in Atmospheric and Oceanic Sciences, Princeton University, New Jersey, USA
2: Department of Geoscience, Aarhus University, Aarhus, Denmark

Ridging and rafting through compression and shear increase the thickness and therefore also the melt resilience of sea-ice packs. Present formulations for these mechanisms assume that ice strength is solely governed by ice thickness, and generally treat the ice pack as a continuum where each cell in the spatial discretization includes many individual ice floes. Particle-based sea ice models with granular interactions generally represent the ice on a floe-by-floe basis, meaning that new formulations are required for including ridging. We show through small-scale, high-resolution Discrete Element Method simulations that floe-floe compression encompasses different deformational modes, where elasticity transitions to frictional sliding and resultant strain weakening at the onset of ridging. We present a generalized formulation based on elasticity and Coulomb friction which is suitable for simulating the contact mechanics of ridging in particle-based sea ice models. On a larger scale, this results in ice-pack dynamics prone to stick-slip, strain localization, and limited compressional resistance.

Slides and video:

• slides (pdf)

Several other presentations to the workshop are also already available.