Wave-influenced formation of new ice: Model building and a test case

Abstract

A parameterization of new ice formation in a wave field has been developed. Detailed processes of new sea ice growth with multiple ice types (nilas, grease, and pancake ice) and associated wave attenuation by different sea ice types are presented and implemented into a coupled ROMS and SWAN model. Sea ice formation includes growth and transformation of frazil, grease, pancake, nilas and solid ice. Ice types are determined by thermal condition and the wave fields. Simultaneously, the attenuation of wave energy through the ice cover is dependent on ice types. The two processes are coupled by COAWST. The resulting coupled model is applied to the Bohai Sea. When compared with in-situ data from oil platforms, the model performed well in distinguishing solid ice, pancake and nilas. When compared with previous ice models without the consideration of new ice types, the appearance of solid ice is delayed, the total ice area and ice volume are increased, solid ice thickness is increased while the type-averaged thickness is reduced and heat flux from the ocean to air is increased during the freezing phase. By considering the new ice formation, wave attenuation in the test case is enhanced.