Sea Ice Properties in High-Resolution Sea Ice Models

Area of Science:

• * Climate modeling
• * Arctic Oceanography
• * Sea ice physics

Background:

• * Accurate simulation of Arctic sea ice dynamics is crucial for understanding climate change impacts.
• * Previous studies suggest model resolution influences sea ice representation, but optimal scales remain debated.

Purpose of the Study:

• * To investigate the impact of uniform horizontal resolution on an Arctic sea ice-ocean model.
• * To assess whether increasing model resolution improves performance against observations.
• * To determine the sensitivity of sea ice properties to resolution within specific scales.

Main Methods:

• * An Arctic sea ice-ocean model was configured at three uniform horizontal resolutions: 6 km, 4 km, and 2 km.
• * Identical sea ice and ocean model parameterizations were used, including viscous-plastic rheology, mechanical ice strength, and ridging parameterizations.
• * The model was driven by consistent atmospheric forcing, and results were compared against NASA IceBridge ice thickness observations.

Main Results:

• * All model resolutions produced similar spatial patterns and temporal variations in ice thickness and motion.
• * Total ice volume, mean ice concentration, ice speed, and thickness fractions showed nearly identical seasonal evolution across resolutions.
• * Increasing resolution from 6 km to 2 km did not significantly improve model performance compared to observations, indicating insensitivity of large-scale properties.

Conclusions:

• * Large-scale Arctic sea ice properties simulated by this model are largely insensitive to resolution increases within the 2-10 km range.
• * Model parameters developed for coarser resolutions may be applicable to higher or multi-scale resolutions.
• * While mean sea ice states were similar, finer resolution (2 km) better captured the spatial and temporal distribution of sea ice leads, though not identical to observations.