甘肃河西绿洲边缘积沙带所表征的气候环境信息

绿洲边缘积沙带的研究是一个新的科学问题。甘肃河西地区经过半个多世纪的防沙治沙，在绿洲边缘形成了一条积沙带。为了研究积沙带的形成和发育与气候环境因子之间的关系，对河西走廊东端至走廊中西部绿洲边缘的积沙带进行了调查。结果表明：① 年降水量是决定积沙带高度和宽度的关键因子；② 降水量是决定植被盖度的关键因子，降水对天然植被盖度的影响大于对包括人工植被在内的植被总盖度的影响，随着降水增加，背风坡植被盖度增加幅度大于迎风坡；③ 积沙带不同样点之间植被盖度的差异主要是由植株个体大小引起的，亦即降水对植株个体大小的影响大于对植株密度的影响。

Climate and Environment Information from Sand Accumulation Belt in Oasis Marginal Zone in the Hexi Corridor,Gansu Province

Formation of sand accumulation belt in oasis marginal zone is one of the new scientific issues.A sand accumulation belt was formed in oasis marginal zone in the Hexi Corridor,Gansu Province after implementing the project of desertification control in recent 50 years.In order to study the relationships between the causes resulting in the formation of sand accumulation belt and the climatic and environmental factors,the sand accumulation belt in the oasis marginal zone was investigated from the eastern part to the central and western parts of the corridor.The results were as follows:(1) Annual precipitation was the key factor affecting the height and width of sand accumulation belt; (2) Climate and environment information was demonstrated by the vegetation,and precipitation was the key factor affecting the vegetation coverage.The effect of precipitation on the natural vegetation coverage was higher than on the total vegetation coverage including artificial vegetation.With the increase of precipitation,vegetation coverage of leeward slope was higher than that of windward slope; (3) Difference of vegetation coverage among the sample sites was mainly caused by the size of plants,that is,the effect of precipitation on plant size was higher than that on plant density.