Interannual Variability in Summertime Sea Fog Over the Northern Yellow Sea and Its Association With the Local Sea Surface Temperature

The Yellow Sea (YS) experiences heavy advection fog during boreal summer, which seriously affects marine transport and harbor activities. Using a set of long-term observations, the present study reveals the interannual variability in the YS fog during its core season (May-June-July, MJJ). The spaceborne lidar supports that a station-based index represents the fog over the northern YS in a seasonal mean sense. The composite soundings according to the YS fog index show that the temperature difference is evident within the boundary layer and becomes indistinguishable in the free atmosphere. This implies that the driver of the MJJ YS fog originates from the bottom boundary of the fog layer. Regression analyses of sea surface temperature (SST) and air-sea fluxes show that the local SST strongly modulates the northern YS fog at interannual scale. The fog during foggier years features a significant decrease in specific humidity, suggesting that the colder sea surface facilitates fog occurrence through strong turbulent cooling. This study identifies the local SST as a key driver of the interannual variation in the northern YS fog during the core season and provides predictive values by linking the YS fog to the preceding SST.