Sea Ice Rheology Experiment (SIREx), Part I: Scaling and statistical
properties of sea-ice deformation fields
Abstract
As the sea-ice modeling community is shifting to advanced numerical
frameworks, developing new sea-ice rheologies, and increasing model
spatial resolution, ubiquitous deformation features in the Arctic sea
ice are now being resolved by sea-ice models. Initiated at the Forum for
Arctic Modelling and Observational Synthesis (FAMOS), the Sea Ice
Rheology Experiment (SIREx) aims at evaluating current state-of-the-art
sea-ice models using existing and new metrics to understand how the
simulated deformation fields are affected by different representations
of sea-ice physics (rheology) and by model configuration. Part I of the
SIREx analysis is concerned with evaluation of the statistical
distribution and scaling properties of sea-ice deformation fields from
35 different simulations against those from the RADARSAT Geophysical
Processor System (RGPS). For the first time, the Viscous-Plastic (and
the Elastic-Viscous-Plastic variant), Elastic-Anisotropic-Plastic, and
Maxwell-Elasto-Brittle rheologies are compared in a single study. We
find that both plastic and brittle sea-ice rheologies have the potential
to reproduce the observed RGPS deformation statistics, including
multi-fractality. Model configuration (e.g. numerical convergence,
atmospheric forcing, spatial resolution) and physical parameterizations
(e.g. ice strength parameters and ice thickness distribution) both have
effects as important as the choice of sea-ice rheology on the
deformation statistics. It is therefore not straightforward to attribute
model performance to a specific rheological framework using current
deformation metrics. In light of these results, we further evaluate the
statistical properties of simulated Linear Kinematic Features (LKFs) in
a SIREx Part II companion paper.