黄土高原地区植被与水循环的关系

Relationship between vegetation cover and water balance in the Loess Plateau

为了改善水土保持效果,研究了黄土高原地区植被和水循环的相互关系。以黄土高原51个小流域为研究区域,分析了归一化植被指数(NDVI)与降水和蒸散发的关系。结果表明:在多年平均降水量越多的区域,植被密度越大,实际蒸散发量也越高。在降水越充沛的区域,NDVI的变差系数较小,植被的年际波动也较小。植被密度大的地区,蒸发效率高,但蒸发系数较低;增加植被会增加地表水和地下径流的分配比例。提高土壤含水量是增加植被覆盖的途径之一。

The relationship between the vegetation coverage and water cycle in the China Loess Plateau was investigated to improve soil and water conservation.The relationship between the normalized difference vegetation index（NDVI） and the water cycle（water rainfall,evapotranspiration） was analyzed in the 51 catchments of the Loess Plateau.The results show that there is high vegetation coverage and high evapotranspiration in the wetter environments.The vegetation coverage is less varied in high precipitation catchments,with little annual variation of the regional vegetation.The vegetation coverage increases with increasing evaporation efficiency and decreasing evaporation ratio.The increased vegetation coverage increases the base flow to surface flow distribution ratio.Thus,increasing of the soil water availability will improve the vegetation coverage.