Abstract:By using the visibility, fog droplet spectra, automatic weather station observation data, the conventional weather data and NCEP Final Operational Global Analysis(FNL) data of eight fog processes from 23 March to 22 April, 2013, the macro and micro processes of spring sea fogs in Xiamen were studied. Results show that the weather situations promoting sea fog in Xiamen include cold front, low pressure with an inverted trough and high pressure running into sea. The 0-1℃ temperature range in sea fog areas of Xiamen was important to sea fog forecast. In a typical case on 17-18 April, 2013 the strong southwesterly flow with enhanced moisture triggered the formation of this sea fog, which provided plenty of vapor for the development of this event. The average fog droplet size distribution was in agreement with the Junge distribution. The analysis on evolution of microphysical characteristics, such as fog droplet number concentration, liquid water content and fog droplet mean radius, indicated that the dominant physical processes were condensational growth on the nuclei and subsequent reversible evaporation.