“京九”铁路大兴段绿化模式动力效应的研究

本文以生态经济型防护林为例 ,对“京九”铁路大兴段绿化模式的动力效应进行了研究。结果表明 :对比旷野农田 (对照点 ) ,防护农田的风速平均约降低 18.9% ,距林带树高 0 .5倍距离处 (0 .5H)风速的降低率可达 30 .0 %左右 ,距林带 4H处至农田中心的风速降低率为 1.8%　 7.1% ,林带的有效防风距离至少可达 4H ;防护农田内理查逊数 (Ri)总体平均值比对照点约高 4 .6 % ,动力速度总体平均值比对照点约低 14 .7%。

Effects of the Afforestation Models along the Beijing-Jiulong Railway on Aerodynamics in Daxing District of Beijing

The effects of the afforestation models along the Beijing Jiulong railway on aerodynamics were studied with the case of eco economical shelterbelt. The trials were conducted in Daxing district of Beijing. The results showed that: the mean wind speed in the farmland protected by the eco economical shelterbelt (protected farmland) decreased by about 18.9% comparing with that in the open wide farmland(CK),and decreased by 30.0% as much at the spot which was 0.5H from the shelterbelt row(H: the tree height), but only 1.8% 7.1% in the range from 4H spot to the center of the protected farmland center; The efficient protective distance was 4H at least; The mean value of Richardson and turbulent coefficient in the protected farmland was 4.6% more and 14.7% less than that in CK respectively.