Abstract/Summary

Earth System Models (ESMs) include a sea ice component to physically represent sea ice changes and impacts on planetary albedo and ocean circulation (Manabe & Stouffer, 1980). Most contemporary sea ice models describe the sea ice pack as a continuum material, a principle laid by the AIDJEX (Arctic Ice Dynamics Joint EXperiment) group in the 1970s (Pritchard, 1980). Initially intended for climate studies, the sea ice components in ESMs are now used across a wide range of resolutions, including very high resolutions more than 100 times finer than those they were designed for, in an increasingly wide range of applications that challenge the AIDJEX model foundations (Coon et al., 2007), including operational weather and marine forecasts. It is therefore sensible to question the applicability of contemporary sea ice models to these applications. Are there better alternatives available? Large advances in high performance computing (HPC) have been made over the last few decades and this trend will continue. What constraints and opportunities will these HPC changes provide for contemporary sea ice models? Can continuum models scale well for use in exascale computing? To address these important questions, members of the sea ice modelling community met in September 2019 for a workshop in Laugarvatn, Iceland. Thirty-two sea ice modelling scientists from 11 countries across Europe and North America attended, spanning 3 key areas: (i) developers of sea-ice models; (ii) users of sea-ice models in an ESM context; (iii) users of sea64 ice models for operational forecasting and (re)analyses. The workshop was structured around 2 key themes: 1. Scientific and technical validity and limitations of the physics and numerical approaches used in the current models 2. Physical processes and complexity: bridging the gap between weather and climate requirements For each theme, 5 keynote speakers were invited to address the motivating questions and stimulate debate. Further details can be found in the Supplementary Material.