Abstract. This study compares the simulation performance of two ice-ocean drag coefficient parameterizations (Scheme1 (original scheme): large-scale roughness parameterization, Scheme2 (newly introduced scheme): small-scale geometric roughness parameterization) for the Bohai sea ice in the 2011/2012 ice season, revealing main component of the ice-ocean drag coefficient (Cdw) and its crucial regulatory role in sea ice dynamic-thermodynamic processes in the Bohai Sea. The findings demonstrate that, for the ice-ocean drag in the thin ice environment of the Bohai Sea, the ice-bottom surface skin drag and the ice floe edge form drag dominate, while the contribution of ice keel-related drag is negligible due to insufficient ice thickness (averaging 20–30 cm). Scheme2 reduces the root mean square error (RMSE) of daily total ice area by 28 % compared to the Scheme1, showing higher simulation accuracy in the overall spatiotemporal ice evolution in the Bohai Sea. While Scheme1 demonstrates closer agreement with the observed length of ice season (underestimating by only 7 days). The result analysis of key sea ice variables and ice-ocean interfacial variables indicates that Cdw can affect the ice velocity through the dynamic feedback mechanism, and the basal freezing/melting through the thermodynamic dual feedback mechanisms.
Received: 06 Sep 2025 – Discussion started: 20 Nov 2025
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The HAMSOM-VICE sea ice model based on Small-scale roughness drag coefficient parameterization, scheme2Jan O. Backhaus, Maier Reimer, Bernhard Mayer, Bin Jia, Libang Xu, Yu Liu, Xue'en Chen, and Donglin Guo https://doi.org/10.5281/zenodo.17054276
The HAMSOM-VICE sea ice model based on Large-scale roughness drag coefficient parameterization, scheme1Jan O. Backhaus, Maier Reimer, Bernhard Mayer, Bin Jia, Libang Xu, Yu Liu, Xue'en Chen, and Donglin Guo https://doi.org/10.5281/zenodo.17054212
We compared two methods to calculate ice-ocean drag coefficient in Bohai Sea. Results demonstrate that in the thin ice environment, the ice-bottom surface skin drag and the ice floe edge form drag are the main components. One method better predicts ice extent, the other better predicts ice season duration. Higher ice-ocean drag melts ice from below and cools water to form new ice. Our findings improve regional ice forecasts, enhancing safety for shipping and coastal industries.
We compared two methods to calculate ice-ocean drag coefficient in Bohai Sea. Results...
