In this study, we perform a stand-alone sensitivity study using the Los Alamos Sea ice model version 6 (CICE6) to investigate the model sensitivity to two Ice-Ocean (IO) boundary condition approaches. One is the two-equation approach that treats the freezing temperature as a function of the ocean mixed layer (ML) salinity, using two equations to parametrize the IO heat exchanges. Another approach uses the salinity of the IO interface to define the actual freezing temperature, so an equation describing the salt flux at the IO interface is added to the two-equation approach, forming the so-called three-equation approach. We focus on the impact of the three-equation boundary condition on the IO heat exchange and associated basal melt/growth of the sea ice in the Arctic Ocean. Compared with the two-equation simulation, our three-equation simulation shows a reduced oceanic turbulent heat flux, weakened basal melt, increased ice thickness, and reduced sea surface temperature (SST) in the Arctic. These impacts occur mainly at the ice edge regions and manifest themselves in summer. Furthermore, in August, we observed a downward turbulent heat flux from the ice to the ocean ML in two of our three-equation sensitivity runs with a constant heat transfer coefficient (0.006), which caused heat divergence and congelation at the ice bottom. Additionally, the influence of different combinations of heat/salt transfer coefficients and thermal conductivity in the three-equation approach on the model simulated results is assessed. The results presented in this study can provide insight into sea ice model sensitivity to the three-equation IO boundary condition for coupling the CICE6 to climate models.

Lei YU;Jiping LIU;Yongqi GAO;Qi SHU

Climate Changes Research Center,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;Department of Atmospheric and Environmental Sciences,University at Albany, State University of New York,Albany,New York 12222,USA;Nansen Environmental and Remote Sensing Center/Bjerknes Center for Climate Research,Bergen N-5007,Norway;Nansen-Zhu International Research Centre,Institute of Atmospheric Physics, Chinese Academy of Sciences,Beijing 100029,China;First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China

大气科学进展（英文版）

[1]Lei YU;Jiping LIU;Yongqi GAO;Qi SHU-.A Sensitivity Study of Arctic Ice-Ocean Heat Exchange to the Three-Equation Boundary Condition Parametrization in CICE6)[J].大气科学进展（英文版）,2022(09):1398-1416

Parametrization,CICE6,parametrize,congelation

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