典型草原区芨芨草灌丛积雪形态与滞雪阻雪能力   总被引：1，自引：0，他引：1  

左合君  闫敏  刘宝河  董智 《冰川冻土》2016,38(3):725-731

通过对典型草原区芨芨草（Achnatherum splendens）灌丛积雪体的调查,研究了灌丛特征（灌丛高度、灌丛迎风侧宽度、灌丛顺风侧长度）对于积雪形态（积雪高度、积雪宽度、雪辫长度）的影响。结果表明：芨芨草积雪形态参数与灌丛特征单一因子间呈显著的幂函数关系（指数<1）,灌丛积雪发育过程及其形态特征是灌丛特征参数共同影响和作用的结果,灌丛高度对积雪高度与雪辫长度影响最大,灌丛迎风侧宽度对积雪宽度影响最大;在灌丛积雪的形成发育过程中,较小灌丛积雪形态发育较快,大灌丛积雪形态发育相对缓慢,不论灌丛特征如何变化,所有灌丛积雪体前期发育迅速,后期发育缓慢;灌丛二维空间滞雪范围模型直接反映灌丛对风力的干扰范围和积雪的潜在范围,间接反映灌丛的滞雪能力;灌丛三维空间阻雪量模型直接反映一定雪源、风况条件下灌丛的阻雪能力。建立的灌丛滞雪范围与灌丛阻雪体积模型,可为典型草原风吹雪区积雪资源估算和雪害植物防治技术提供理论依据。  相似文献   

Snowmelt energetics at a shrub tundra site in the western Canadian Arctic   总被引：1，自引：0，他引：1  

P. Marsh  P. Bartlett  M. MacKay  S. Pohl  T. Lantz 《水文研究》2010,24(25):3603-3620

Snow accumulation and melt were observed at shrub tundra and tundra sites in the western Canadian Arctic. End of winter snow water equivalent (SWE) was higher at the shrub tundra site than the tundra site, but lower than total winter snowfall because snow was removed by blowing snow, and a component was also lost to sublimation. Removal of snow from the shrub site was larger than expected because the shrubs were bent over and covered by snow during much of the winter. Although SWE was higher at the shrub site, the snow disappeared at a similar time at both sites, suggesting enhanced melt at the shrub site. The Canadian Land Surface Scheme (CLASS) was used to explore the processes controlling this enhanced melt. The spring‐up of the shrubs during melt had a large effect on snowmelt energetics, with similar turbulent fluxes and radiation above the canopy at both sites before shrub emergence and after the snowmelt. However, when the shrubs were emerging, conditions were considerably different at the two sites. Above the shrub canopy, outgoing shortwave radiation was reduced, outgoing longwave radiation was increased, sensible heat flux was increased and latent flux was similar to that at the tundra site. Above the snow surface at this site, incoming shortwave radiation was reduced, incoming longwave radiation was increased and sensible heat flux was decreased. These differences were caused by the lower albedo of the shrubs, shading of the snow, increased longwave emission by the shrub stems and decreased wind speed below the shrub canopy. The overall result was increased snowmelt at the shrub site. Although this article details the impact of shrubs on snow accumulation and melt, and energy exchanges, additional research is required to consider the effect of shrub proliferation on both regional hydrology and climate. Copyright 2010 John Wiley & Sons Ltd and Crown in the right of Canada.  相似文献   

沙地柠条(Caragana)灌丛微生境节肢动物群落特征     

刘任涛  郗伟华  刘佳楠  赵娟  常海涛 《中国沙漠》2018,38(1):117-125

以宁夏荒漠草原柠条（Caragana）灌丛林地为研究对象,于2011年春、夏、秋季,利用陷阱诱捕法,调查了灌丛微生境节肢动物群落分布特征。结果表明：（1）调查共获得节肢动物9目31科32个类群,分属于4种功能群（植食性、捕食性、腐食性和杂食性）。其中,优势类群为蚁科（Formicidae）和拟步甲科（Tenebrionidae）,个体数占总个体数的71.97%;常见类群有7科8个类群,个体数占总个体数的19.72%;其余22个类群为稀有类群,个体数仅占总个体数的8.30%。（2）随着季节变化,灌丛内外节肢动物类群组成和个体数分布均发生改变。春季灌丛内外均包括优势类群、常见类群和稀有类群;夏季灌丛内外均包括优势类群,而灌丛下仅有常见类群,无稀有类群,灌丛外既没有常见类群也没有稀有类群;秋季灌丛内外均有优势类群和常见类群,但灌丛内外均无稀有类群。（3）夏季灌丛内外共有类群数最少,相似性指数最低,秋季次之,而春季灌丛内外共有类群数最多,相似性指数也最高。（4）春季和秋季,灌丛内外微生境中节肢动物个体数、丰富度和Shannon指数均无显著差异（P>0.05）。夏季,节肢动物个体数灌丛内外无显著差异性（P>0.05）,但丰富度和Shannon指数均表现为灌丛内显著高于灌丛外（P<0.05）。（5）春季灌丛内外捕食性、植食性和杂食性节肢动物的个体数和丰富度均无显著差异性（P>0.05）;但是,腐食性动物个体数和丰富度均表现为灌丛内显著高于灌丛外（P<0.05）。夏季,仅有捕食性动物丰富度呈现出灌丛内显著高于灌丛外（P<0.05）,而其他指标灌丛内外均无显著差异性（P>0.05）。秋季,每种功能群动物的个体数和丰富度灌丛内外均无显著差异性（P>0.05）。沙地灌丛内外生境中节肢动物的空间分布,既与灌丛本身生理生态学特性相关,也与季节性降雨和温度等气象条件的改变密切相关。  相似文献