The role of the heat exchange coefficient at the ice/ocean interface in Bohai Sea ice modeling

Abstract

The role of the heat exchange coefficient (HEC) at the ice/ocean interface in Bohai Sea ice simulations using the HAMSOM ice-ocean coupled model has been studied by sensitivity research and mechanism analysis. Our simulations indicate that the HEC plays a major role during the ice melting period, and plays a very minor role during the ice growth period. The HEC can modulate ice freezing/melting at the ice/ocean interface through two important response mechanisms in the thermal ice-ocean fields. The magnitude of both freeze rate of newly formed ice and melt rate of ice base increases with the HEC. We also found that the values of the parameterized HEC and oceanic heat flux in the marginal ice zone (MIZ) are larger than those in the inner ice area in the Bohai Sea. The relationship between the HEC and friction velocity at the ice/ocean interface (i.e., the parameterization proposed by McPhee (1992)) was also introduced into the model to obtain the spatiotemporally varying HEC. The simulation result of ice area shows that the simulations using the parameterized HEC have the best performance, providing a 53% improvement compared with the simulations using a constant HEC (0.001, the value used in our previous study (Jia and Chen, 2020).