EVOLUTION OF LIQUID WATER CONTENT IN A SEA FOG CONTROLLED BY A HIGH-PRESSURE PATTERN

On March 16-17,2008,a sea fog occurred in Dianbai in the west of Guangdong Province and was accompanied by a high-pressure synoptic system.Using comprehensive observation datasets,this study analyzes the evolution of liquid water content during this sea fog and investigates the relationships between liquid water content and the average diameters and count densities of fog droplets,air temperature,wind speed and turbulence exchanges.The main results are presented as follows.(1)The sea fog showed a quasi-periodic oscillation characteristic,i.e.,it developed,disappeared and then developed again.(2)During the sea fog,the number of fog droplets changed significantly while the changes in average diameter of the fog droplets were relatively small.The development and disappearance of the sea fog correlated significantly with the fog droplet numbers.(3)The air-cooling mechanism played a significant role in sea fog formation and development.However,the influences of this mechanism were not evident during fog persistence.(4)During sea fog formation,weak turbulence exchanges were helpful for fog formation.During sea fog development and persistence,liquid water content increased when turbulence exchanges weakened,and vice versa.The changes in turbulence exchanges were closely related to the quasi-periodic oscillations observed in sea fog presence.