摘要
为了解海防林对台风的防护效应,以惠安赤湖国有防护林场监测站收集的“杜苏芮”台风登陆前后的气象数据为材料,分析了台风登陆前后近地层的风速、风向、湍流强度、防风效能和气流加速率等的特征规律。结果表明:(1)台风登陆前后的平均风速和风向时程变化特征满足了台风眼区经过的条件,平均风速曲线呈“M”形双峰分布,通过采集到的台风眼区、眼壁和外围强风的完整风况数据,完整展示了台风经过林带前后风速、风向的演变过程。(2)湍流强度的时程整体变化趋势随着台风靠近和离去呈现增大-减小-剧增-回落的过程,尤其台风后风圈影响的区域,湍流强度剧烈增大,强度可增大2倍以上。(3)向岸风在垂直方向上,弱风或强风的防风效能随高度增加而降低,高度相同,林带后弱风的防风效能小于强风;水平方向上,林内及林带后1H和5H处防风效能最好,在高度3 m平均防风效能为49.57%~93.93%,在高度9 m平均防风效能为44.04%~90.10%。离岸风在垂直方向上,随着气流靠近林带,弱风或强风的气流加速率随高度增加而增大,林带后1H高度3 m气流加速率平均为0.2193,高度9 m气流加速率平均为0.3242,林内气流加速率达到最低值;而风越过林带后,弱风风速恢复到88%左右,强风的气流则有个加速的过程。
In order to understand the protective effect of coastal defense forest on typhoon,the meteorological data of Typhoon“Doksuri”before and after landing collected by the monitoring station of Chihu State-owned Protective Forest Farm in Hui’an were used as materials to analyze the characteristic rules of wind speed,wind direction,turbulence intensity,windbreak effect and airflow acceleration rate in the near-ground layer before and after typhoon landing.The results showed as the following three aspects.(1)The time-history variation characteristics of the average wind speed and wind direction before and after the landing of typhoon met the conditions of the typhoon eye area.The average wind speed curve showed a“M”-shaped bimodal distribution.The collection of the complete wind data of the typhoon eye area,the eye wall and the peripheral strong winds fully demonstrated the evolution process of wind speed and wind direction before and after the typhoon passing through the forest belt.(2)The overall trend of the time history of turbulence intensity showed the process of increasing-decreasing-surging-falling as the typhoon approached and departed.Especially in the area affected by the wind circle after the typhoon,the turbulence intensity increased sharply,and the intensity could increase by more than twice.(3)For the onshore wind,when it was in the vertical direction,the windbreak efficiency of weak wind or strong wind decreased with the increase of height,and at the same height,the windbreak efficiency of weak wind behind the forest belt was lower than that of strong wind;when it was in the horizontal direction,the windbreak efficiency in the forest and at the 1 H and 5 H behind the forest belt was the best,the average windbreak efficiency was 49.57%-93.93%at the height of 3 m,and the average windbreak efficiency was 44.04%-90.10%at the height of 9 m.For the offshore wind,when it was in the vertical direction,as the airflow was close to the forest belt,the airflow acceleration rate of weak wind or strong wind
作者
朱炜
林捷
施能深
吴国伟
Zhu Wei;Lin Jie;Shi Nengshen;Wu Guowei(Fujian Forestry Academy of Sciences,Fuzhou 350012,China;Fujian Province Hui’an Chihu State-owned Protective Forest Farm,Quanzhou 362131,China)
出处
《防护林科技》
2024年第3期1-6,14,共7页
Protection Forest Science and Technology
基金
福建省科技计划项目(2021R1010001)
国家林业局南方山地用材林重点实验室、福建省森林培育与林产品加工利用重点实验室资助。
关键词
木麻黄
基干林带
台风
杜苏芮
防风效应
Casuarina equisetifolia
main shelterbelt
typhoon
Doksuri
windbreak effect
