稀疏天然植被对输沙量的影响  

Influence of Sparse Natural Vegetation on Sand-transporting Quantity

作　　者：凌裕泉[1] 屈建军[1] 金炯[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《中国沙漠》2003年第1期12-17,共6页Journal of Desert Research

基　　金：中国科学院资源环境领域知识创新工程重大项目(KZCX2 304);国家自然科学基金项目(49971013);国家基础研究发展规划(973)项目(19990305)

摘　　要：在内陆沙漠和海滨沙丘地区,均生长着不同类型低密度的天然植被,它对风沙流活动和风成地貌形态的形成与演变都具有一定的影响,但在大多数情况下是不足以防止风沙危害的。因此,为了达到防沙的要求,其中就存在着一个稀疏天然植被的有效临界密度问题。为此,通过对3个不同类型植物种、10组植株密度的风洞模拟研究表明,当平均输沙率减少到流沙表面的50%左右时,其相应的植物株密度为:呈紧密结构半球状植株密度为6株·m-2;呈漏斗形上密下疏者为7株·m-2和呈线状具有弯曲弹性的植株介于6～10株·m-2之间。在各种植株密度的影响下,输沙率与有效起沙风呈正比关系,即q=a×(VL-Vt)b。Different types of sparse natural vegetation occurring in inland deserts and coastal dune\|fields exert a certain influence on the blown sand activity and the development of aeolian sand landforms. However, in most cases their densities are insufficient to halt blown sand damages. To be effective in halting blown sand damages, the natural vegetation in excess of critical density is required. Simulation experiments on 10 plant\|density levels of three types of plant species showed that when mean sand transporting quantity over moving sand surface decreases by 50% or so, the corresponding plant densities should be 6 individuals\5m-2  for the dense structure planted in semi\|sphere, 7 individuals\5m-2 for the funnel\|shaped structure planted in top\|dense and base\|thin and 6～10 individuals\5m-2 for the linearly but bent elastic planted structure. Under different plant densities, the sand transporting quantity is directly positive proportional to the effective threshold wind velocity of sand grain: \%q=a (VL-Vt)b\%.

关 键 词：输沙量 天然植被 风沙流 输沙率 有效临界密度 风洞 

分 类 号：X169[环境科学与工程—环境科学]