Abstract:Based on the observation data of island stations, buoy sites and coastal stations in Shanghai during 2016-2020, sea fog events at six stations are identified and classified. On this basis, the spatio-temporal characteristics of sea fog events and the changes in space, season, duration, intensity, start and dissipation times of different types of sea fog are analyzed. The results show that there are generally 20-30 sea fog events in different regions throughout the whole year, but they have significant differences in time and space. Radiation fog is the most common type of sea fog, followed by precipitation fog. Advection fog occurs more frequently at Yangshan and offshore sea areas. The seasonal variation of different types of fog varies greatly in different sea areas. In the Yangtze River Estuary sea area, radiation fog and precipitation fog occur every month, with radiation fog being the main type. Advection fog mainly occurs in winter and spring, but its frequency is relatively low. The Jinshan and Yangshan sea areas are dominated by radiation fog every month, with precipitation fog and advection fog mainly seen in spring, summer and winter. The duration of advection fog is generally longer, while the durations of precipitation fog and radiation fog are shorter. The lowest atmospheric visibility value in precipitation fog events is generally higher than that in radiation fog and advection fog, and advection fog often produces the most of severe fog events. Precipitation fog can occur at all the time of the day, while radiation fog and advection fog mainly appear at night. The dissipations of radiation fog and advection fog mainly occur in 1-5 hours after sunrise, and the dissipation time of precipitation fog is more dispersed.