南沙沿海防护林对“韦森特”台风的防护效应

Protection effects of Nansha coastal shelterbelt forests on typhoon Vicente

台风是影响我国沿海及内陆地区重要的天气系统,为了探索、了解沿海防护林对登陆台风强风过程的湍流特性的影响及其防风效应,本研究利用设置在南沙沿海防护林临海边和相距70 m的林内自动气象站实时观测了2012年的1208号"韦森特"台风过程中气象因子的时程变化,重点分析了"韦森特"台风过程强风时段的平均风速和风向特征。研究发现"韦森特"台风过程的风速时程曲线出现两次极值风速,呈M型变化,强风风向角出现大幅度的转换;南沙沿海防护林对"韦森特"台风最大风速减弱系数为0.58,对整个台风过程的风速减弱系数为0.7,林内和海边的平均湍流强度比值为1∶2.25,南沙沿海防护林对"韦森特"台风的防风效应明显。

As one of the most destructive and disastrous weathers, the typhoon involving rain or strong wind exerts considerable adverse effects on people’s life and the economy. By taking the typhoon Vicente in 2012 as a case, based on the wind speed data and pressure pattern observed by two automatic meteorological stations 70 meters apart away from each other, located at the forests in Nansha coastal shelterbelt, the time history changes of meteorological factors of Vicente typhoon No.1208 in 2012 were observed by real-time, and the average wind speed and wind direction characteristics of strong wind periods of Vicente typhoon No.1208 were emphatically analyzed. The results show the wind velocity time-history curve that took on a M-type change presented extreme wind speed twice, the wind direction angle of the strong wind （10-minutes mean wind speed was higher than 11m/s） changed substantially;The maximum wind speed reduction coefficient of the shelterbelts to Vicente typhoon No.1208 was 0.58, the reduction coefficient to the whole process of the typhoon wind speed was 0.70 due to the role of shelterbelts;The ratio of mean turbulence intensity values of the typhoon was 1∶2.25. The coastal protection forests possessed an obvious windbreak effect on strong typhoon Vicente and has great meaning on the coastal ecological environment.