Concurrent Variations in Air–Sea Heat Fluxes and Sea Ice Extensions Under Cold‐Air Outbreaks: The First Joint Buoy–Cruise Observational Results in the Bohai Sea

Abstract The air–sea interface near seasonal ice edges notably regulates the regional climate but remains poorly understood. We present the first coordinated buoy–cruise measurements in the Bohai Sea—the world's lowest‐latitude seasonal ice zone—during the winter of 2024–2025. This season featured an initial stable ice period followed by three advance–retreat cycles triggered by cold‐air outbreaks. During the advance phases, strong northerly outbreaks created considerable air–sea contrasts and unstable stratification, leading to high mean and maximum sensible and latent heat fluxes. During the retreat phase, southwesterly winds originating from anticyclones transported warmer, more humid air over the region, which diminished the air–sea gradients and stabilized the boundary layer, thereby suppressing turbulent heat fluxes. These observations provide process‐level insights into mid‐latitude ice–ocean–atmosphere co‐variability and highlight priorities for improving predictions near the coastal ice edges.