Sensitivity of NEMO4.0-SI³ model parameters on sea ice budgets in the Southern Ocean

Abstract. The seasonally dependent Antarctic sea ice concentration (SIC) budget is well observed and synthesizes many important air–sea–ice interaction processes. However, it rarely simulated in Earth system models, means to tune the former are not understood. In this study, we investigate sensitivity of 18 key NEMO4.0-SI3 (Nucleus for European Modelling Ocean coupled with Sea Ice Integrated Initiative) model parameters on modelled SIC volume (SIV) budgets Southern based a total 449 runs two global analysis methods. We found that SIV sensitive strength, thermal conductivity snow, number categories, related lateral melting, ice–ocean drag coefficient air–ice coefficient. An optimized can reduce root-mean-square error between by about 10 %. This implies more accurate calculation velocity optimizing simulation, which unlikely be achieved perfectly simply tuning presence biased atmospheric forcing. Nevertheless, combinations were recommended, as they could yield better extent than when using standard values.