Regional sensitivity of Bohai Sea Ice to thermal and wind forcing: A Delft3D modeling study

Sea ice in the Bohai Sea exhibits pronounced seasonal variability and strong spatial heterogeneity, yet the relative roles of atmospheric temperature and wind forcing remain insufficiently quantified. Here we apply a fully coupled Delft3D FLOW–ICE modeling framework to the Bohai Sea to disentangle regional variation of thermal and dynamic controls on ice evolution for the first time. Eight modeling experiments were conducted by combining idealized constant forcing with historical reanalysis winters representing heavy (2009), light (2013), and normal (2017) ice conditions. The present model results demonstrate that air temperature governs the seasonal maximum coverage and thickness of sea ice, whereas wind primarily redistributes the ice field and modulates centroid migration without increasing bay-wide maxima. Bohai Sea ice exhibit strong bay-scale contrast, with persistent thick ice in Liaodong Bay, near-absence in Bohai Bay during warm winters, and intermediate responses in Laizhou Bay. Stage-dependent regression analysis across growth and melt phases further confirms temperature as the dominant predictor, with wind effects varying with region and season. These findings provide new mechanistic insights into the interplay between thermal and dynamic forcing in a marginal sea and offer practical implications for navigation safety, port operations, aquaculture, renewable energy, and coastal adaptation in northern China.