Abstract: In order to understand the windbreak function of mangrove during tropical storm (typhoon), an observation with automatic weather station was conducted on the windbreak effect of Sonneratia apetalaS. caseolaris artificial mangrove in Dongzhaigang of Hainan Province, South China during the lashing period of tropical storm “Francisco” in 2007 (from 0:00 to 15:00, September 24, 2007). The mean value of the wind speed observed at various sites was lower at 1H (average tree height) distance of the forest back than at 1H distance of the forest front, and the wind speed behind the forest decreased significantly, indicating a noticeable windbreak service of the forest. The windbreak effect during the lashing period of tropical storm was 28%-68%, being less than that (65%-77%) under nontropical storm circumstances and decreased as wind speed increased. During the tropical storm, the prevailing wind direction was 45 degree. When the wind direction was nearly vertical to the forest, the damping effect on wind speed was much better. In sum, the windbreak performance of the S. apetala-S. caseolaris artificial mangrove was obvious during tropical storm.  

Key words: land surface model, root parameters, land surface flux.