A Numerical Study Of Impact Of Topography On Sea Breeze Circulation In Cloudy Condition Over The Hainan Island

The influence of complex topography on the sea breeze circulation pattern over the Hainan Island is discussed using WRF model (Version 3.7) in the cloudy condition. A case study are investigated about its characteristics of the sea breeze circulation and cloud water pattern with different terrain heights on both horizontal and vertical structures. It appears that topography matters on the pattern of sea breeze circulation containing the cloud water mixing ratio.From the study, a nearly complete structure of sea breeze, which is raised by the mountains, is revealed in the western and northern Hainan Island. When the mountains become more higher, the cloud water and convergence zone of sea breeze locates in further inland due to the blocking effect of the southern mountainous area.At 15:00, the temperature equipotential line where locates in western coastal area, is denser than eastern Hainan Island. Besides, the higher terrain height in the mountainous is, the warmer the potential temperature is. The water vapor in windward slope is abundant, while distribution of maximal water vapor mixing ratio in cloudy condition is much more than in the clear condition. The strength of the cloud and rain water mixing ratio in the Hainan Island reach a maximum value at 15:00 due to the lifting effect of the mountains. When strongest sea breeze prevails at noon, the mean vertical velocity increases apparently, and the intensity is closely related to the terrain height. In clear condition, the strongest sea breeze circulation,containing both the maximum wind velocity and the sea breeze depth, is inconspicuously greater than in cloudy condition. It results in significant reduction on mean wind velocity in the Hainan Island in clear condition after moving the terrain, while 2?3 m·s-1 decrease in cloudy condition. Besides, the impact of topography on sea breeze circulation in cloudy condition is slightly inferior.