NEMO-Bohai 1.0: a high-resolution ocean and sea ice modelling system for the Bohai Sea, China

Abstract

Abstract. Severe ice condition in the Bohai Sea could cause serious harm to maritime traffic, offshore oil exploitation, aquaculture, and other economic activities in the surrounding regions. In addition to providing sea ice forecasts for disaster prevention and risk mitigation, sea ice numerical models could help explain the sea ice variability within the context of climate change in marine ecosystems, such as that of spotted seals, which are the only ice-dependent sea animal that breeds in Chinese waters. Here, we developed NEMO-Bohai, an ocean-ice coupled model based on the Nucleus for European Modelling of the Ocean (NEMO) model version 4.0 and Sea Ice modelling Integrated Initiative (SI3) (NEMO4.0-SI3) for the Bohai Sea. This study will present the scientific design and technical choices of the parameterizations for the NEMO-Bohai model. The model was calibrated and evaluated with in situ and satellite observations of ocean and sea ice. The model simulations agree with the observations with respect to sea surface height (SSH), temperature (SST), and salinity (SSS). The seasonal variation of the sea ice area is well simulated by the model compared to the satellite remote sensing data for the period of 1996–2017, and there are similar overall statistics in the occurrence dates of annual maximum sea ice area. The simulated sea ice thickness and volume are in general agreement with the observations with slight over-estimations. NEMO-Bohai is able to simulate seasonal sea ice evolution and long-term interannual variations. Hence, Nemo-Bohai is intended to be a useful tool for long-term ocean and ice simulations as well as the ocean and climate change studies.