An Assessment of Antarctic Sea-ice Thickness in CMIP6 Simulations with
Comparison to the Observations
Abstract
This study assesses less-explored Southern Ocean sea-ice parameters,
namely Sea-ice Thickness and Volume, through a comprehensive comparison
of 26 CMIP6 models with reanalyses and satellite observations. Findings
indicate that models replicate the mean seasonal cycle and spatial
patterns of sea-ice thickness, particularly during its maxima in
February. However, some models simulate implausible historical mean
states compared to satellite observations, leading to large inter-model
spread. September sea-ice thickness is consistently biased low across
the models. Our results show a positive relationship between modeled
mean sea-ice area and thickness in September (i.e., models with more
area tend to have thicker ice); in February this relationship becomes
negative. While CMIP6 models demonstrate proficiency in simulating Area,
thickness accuracy remains a challenge. This study, therefore,
highlights the need for improved representation of Antarctic sea-ice
processes in models for accurate projections of thickness and volume
changes.