近50年来黄土高原中部水土流失的时空演化特征

黄土高原是我国水土流失最严重的区域之一.近50年来，随着全球气候变化和人类活动对地表的影响，水土流失发生了巨大变化.为了揭示黄土高原水土流失的时空演化特征，该文选择了黄土高原中部4种典型地貌区域，以年径流深度和年侵蚀模数为水土流失过程参数，采用波谱分析方法和多元回归分析方法对该地区水土流失的周期和演化趋势进行了探讨，分析了不同地貌区域的水土流失特征及近50年来各地貌区域水土流失的演化过程.结果表明，近50年来，黄土丘陵沟壑区水土流失无明显变化，黄土残塬沟壑区和水土流失较轻的土石山区水土流失总体上都存在着不同程度的持续减弱，而水土流失较轻的黄土山区则表现出总体递增的趋势. 黄土高原各地貌区都存在20～21 a、6～7 a和2～4 a的变化周期. 周期外延和多元回归的混合模型，可以很好地模拟预报黄土高原水土流失的周期波动与总体递变相叠加的演化趋势，可作为黄土高原水土流失监测与预测的有效方法. 

Spatial_temporal succession characteristics of soil and water loss in the central Loess Plateau during the last 50 years

The Loess Plateau is one of the most serious regions of soil and water loss in China.Soil and water loss has changed extremely with the global climate change and rebuilding of LUCC in the last 50 years.Depth of annual runoff and annual erosion modulus were chosen as the indicators of soil and water loss,and the succession of soil and water loss in four typical morphogenetic zones in the central Loess Plateau during last 50 years was analyzed by Fourier transform.Based on this,period models were created to predict soil and water loss by spectrum analysis.The results showed that soil and water loss did not change significantly in the loess hilly zone and it decreased in the loess gully zone and loess_rock mountain zone,while it increased in the loess mountain zone.Periods of 20(--)21 years,6(--)7 years and 2(--)4 years in the change of soil and water loss existed in all morphogenetic zones of the Loess Plateau.It is a good way to predict the succession trend of soil and water loss by mixed model of period change and multi_regression,and this is very useful in monitoring soil and water loss on the central Loess Plateau.