摘要
建立沿海防护林主要目的是减弱海陆风的风力及其引起的风暴潮、飞沙、飞盐对岸基受防护区域的破坏,防护林区域风场的特征是评估其防护功能的基础。通过分析广东省滨海典型木麻黄(Casuarina equisetifolia)防护林带2009年7月—2010年6月的梯度系统观测数据,对木麻黄防护林带前沿海滨,防护林带内垂直分层风速、风向及林带后不同位置周年连续观测的风速、风向数据进行了统计,分析比较了典型木麻黄防护林带的风场特征及其防风效能。结果表明:(1)林带前沿观测到海陆风频率为64%,林冠上方观测到的海陆风频率为73%,表明观测区域是以海陆风为主风向。(2)在最大风速情景下,防护林带冠层上方、林带后1倍、5倍、10倍树高处的防风效能分别为23.2%、33.1%、6.6%、10.0%、15.1%;在年均风速情景下,防护林带冠层上方、林带后1倍、5倍、10倍树高处的防风效能分别为26.8%、65.0%、23.4%、28.4%。(3)1 a的观测期内月均风速最高为4月的3.77 m·s-1,最低为8月的1.66 m·s-1。(4)防护林区域不同防护位置风速平均日变化规律是白天高于夜晚,日出后风速逐渐升高,到午间11:00—13:30时风速最高,13:30时后风速逐渐减弱,19:00—7:00时平均风速变化比较平稳。(5)防护林带内不同高度风速日均整时变化趋势相近,相比冠层内部各高度,冠层顶部高20 m处风速最高,且有更多比日变化振幅小的脉动波动。
Wind character studies are the base to evaluate the ecosystem service of shelterbelt on wind reduction. A gradient observation system on wind speed and wind direction were set in the typical coast shelterbelt in Guangdong province. Based on the one-year-observed date from 2009.07 to 2010.06, the characteristics of the wind speed,wind direction and wind reduction efficiency in the shelterbelt of Casuarina equisetifolia were analyzed respectively. Results showed that：（1） The maim type of wind direction observation area was by sea-land breeze. The ratios of sea-land breeze in front of the shelterbelt and above the shelterbelt canopy were 64% and 73%, respectively.（2） Wind reduction efficiency（Ex） was 23.2%, 33.1%, 6.6%, 10.0% and 15.1% in the scenario of maximum wind and 26.8%, 65.0%, 23.4% and 28.4% in scenario of annual mean wind speed respectively at the position above canopy and of 1, 5, 10 times the average tree height behind the shelterbelt.（3） During one-year observation period, the highest monthly average wind speed was 3.77 m · s-1 in April and the lowest speed was 1.66 m · s-1 in August.（4） The wind speed in the daytime was higher than that in nighttime. After sunrise, the wind speed increased gradually and peaked at 11：00—13：30 and then declined gradually in the afternoon. Average wind speed was relatively stable at 19：00—7：00.（5） The trends of diurnal average wind speed variation were similar at different height layers in the shelterbelt. While the average wind speed at the position of 20-meter-height above the canopy was obviously larger than that inside the canopy.
出处
《林业与环境科学》
2016年第4期1-6,共6页
Forestry and Environmental Science
基金
广东省林业科技创新项目(2013KJCX011-01
2015KJCX024)
国家林业平台补助"广东沿海森林生态站运行补助"(2015-LYPT-DW-091)
关键词
沿海
木麻黄
防护林
风速
风向
时空特征
coastal
Casuarina
shelterbelt
wind speed
wind direction
temporal-spatial characteristics
