华北山区东台沟小流域沟道土壤水分动态特征

Soil Moisture Dynamics in Dongtaigou Catchment of Northern China

通过利用2004年-2007年华北山区密云水库上游东台沟小流域沟道土壤水分监测数据,分析沟道土壤水分季节和年际动态变化,并采用最大熵谱分析法分析了沟道土壤水分的周期特征。结果表明:2004年-2007年东台沟流域沟道土壤体积含水量(<100cm)变化范围在5%～30%之间,季节性波动明显。土壤水分季节动态过程表现为春季土壤水分显著回升,上游上升幅度大于10%;夏季受降雨影响波动剧烈;秋季下降并趋于稳定,波动幅度小于2%;冬季土壤处于冻结状态。方差分析显示沟道土壤水分在不同水平年间差异显著。平水年土壤含水量变异系数最大值均出现在100cm深处;枯水年,在沟道上游表层20cm深处土壤含水量变异系数为最大值。沟道各层土壤水均具有明显的年周期和5～6个月的季节性变化周期。

Using the soil moisture data from 2004-2007 in the Dongtaigou Catchment,which locates in the upper reaches of Miyun Reservoir,seasonal dynamics and annual variation of the soil moisture are investigated,and cycle features through maximum entropy spectral analysis method are discussed The results show that the soil moisture content is between 5%～30% with much seasonal fluctuations.Covariance analysis indicates that there is significant difference between different level years.Seasonal fluctuations can be divided into 4 stages：in spring,soil moisture increases distinctly,and by more than 10% in the upriver sites;in summer,soil moisture fluctuates rapidly influenced by rainfall;in autumn,soil moisture decreases and remains relatively constant;and in winter,soil moisture become frozen.Each layer of soil moisture has an obvious annual period,as well as a 5～6 months seasonal variation period.