Inter-comparison of global ice sea coupling model based on NEMO and MITgcm

Abstract

Two global high-resolution ice sea coupling model established on basis of NEMO and MITgcm were systematically evaluated, by comparing the climatology simulation results of their sea surface temperature, sea surface salinity, sea surface current and sea ice area with SODA3, EN4, and NSIDC. The simulation accuracy of each element in the global and typical sea areas are quantitatively evaluated. The global RMSE of SST modeled by NEMO and MITgcm are 0.38°C and 0.46°C, respectively. NEMO had lower SST RMSE in strong current areas, especially in Kuroshio and Antarctic circumpolar currents, while MITgcm had better SST simulations in low-middle latitudes and most of Arctic Ocean. The global RMSE of SSS of NEMO and MITgcm is 0.47psu and 0.69psu, and the highest RMSE of SSS of the two models are in the Arctic Ocean. The RMSE of NEMO and MITgcm on surface current simulations are 0.0465m/s and 0.0474m/s, and both NEMO and MITgcm have high RMSE in their simulations of strong currents. The sea ice area simulated by NEMO and MITgcm are basically the same as that of NSIDC in spatial morphology, and the absolute value of the relative error of sea ice area in the Antarctic and Arctic of the two models are within 25%. The inter-comparison and evaluation results provide a reference for the product application and the model improvement of the two high-resolution ice sea coupling models.