Abstract:By using the surface observation data at 12 stations in the coast of West Guangdong from 2000 to 2010 and the sea fog observation data on Donghai Island in Zhanjiang during March 2010, the climatic and microphysical characteristics of coastal fog are statistically analyzed. Results show that the fog day number has a variation tendency in West Guangdong, i.e. western (17.8 d·a-1)>eastern (7.7 d·a-1)> central (3.5 d·a-1). The annual change is significantly different and has a gradually rising trend during 2000—2010 except the 2008. There are more fog days in winter and spring, and less in summer and autumn. Generally most fog events in a certain day occur between 02:00 and 08:00 BT, and have an average probability of 50.8%. The duration of sea fog process is mostly between 1 and 3 days. The comprehensive weather conditions of fog generation mainly are that wind speed is ≤7 m·s-1 and wind directions are NNE-ESE and calm wind, and the appropriate air temperature is between 15.0 and 25.0℃, and the 3 h pressure change is in an interval of -3.5-2.5 hPa, and depression of the dew point continuously approaches to 0.0-2.0℃. The synoptic situations favorable for the fog formation and development on the Leizhou Peninsula can be roughly divided into five classes: high pressure system, low trough system, cold front, stationary front, saddle type pressure field or isobaric field. The droplet size distribution is quite different during fog process. The average droplet size distribution is generally consistent with exponential distribution, and the type of the average droplet size distribution is similar to the “single peak” structure. Drops significantly bias the small end of the spectrum, and the droplet spectrum diameters mainly appear in 2-10 μm.