黑河流域荒漠区土壤水分对降水脉动响应  

Response of Soil Moisture to Rainfall Pulse in Desert Region of the Heihe River Basin

作　　者：刘冰[1] 赵文智[1] 常学向[1] 李守波[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所临泽内陆河流域研究站/黑河生态水文与流域科学重点实验室,甘肃兰州730000

出　　处：《中国沙漠》2011年第3期716-722,共7页Journal of Desert Research

基　　金：国家自然科学基金项目(41071019;41001015);中国科学院寒区旱区环境与工程研究所人才基金(51Y084931)资助

摘　　要：利用气象站资料,对黑河流域荒漠区降水特征及其土壤水分对降水脉动响应进行了系统研究。结果表明,荒漠区降水属于降水脉动事件,降水前后土壤水分特征存在显著差异,且随土层增加差异逐渐变小。土壤水分在降水量、土壤深度和降水前后的差异极显著,交互效应也极显著(P<0.0001),表明荒漠区土壤水分对降水脉动具有显著的响应现象。土壤水分的降水脉动响应表现为降水后土壤含水量激增,在蒸散作用下缓慢减小。降水前后土壤含水量的时间序列变异规律均能较好地拟合成变异函数的理论模型。降水前后土壤含水量随机变异均小于结构性变异,反映出荒漠区土壤水分在时间尺度上具有较强的自相关性格局。降水使土壤水分空间结构差异呈现下降趋势,在时间序列上异质性降低。The meteorological data were collected at the desert-oasis ecotones to study rainfall characteristics and response of soil moisture to rainfall pulse in desert regions of the Heihe River basin. The results indicated that the rainfall pattern was characterized as rainfall pulse in arid regions. Soil moisture differed significantly before and after rainfall, and decreased gradually with increasing of the soil depth in desert regions. Soil moisture differed significantly for different rainfall volumes, soil depths, before and after rainfall, and the interactive effects （P〈0. 0001）, which indicated that the response of soil moisture to rainfall pulse, was significant. Rainfall pulse led to a sharp increase of soil water content after rainfall, then decreased slowly under the conditions of evapotranspiration until rainfall supplement. The variation pattern of time series for soil moisture before and after rainfall can be fitted to semivariograms models. The structural ratios （C/（ C0 ＋ C）） of soil water content were bigger than 0. 910, and there was possibility that the spatial heterogeneity mainly resulted from structural reason since the stochastic variation is smaller than the structural variation, which can reflect that there was a quite strong autocorrelation pattern for soil moisture in time scales. Rainfall pulse decreased the difference of spatial structure for soil moisture, and it led to decrease of the spatial heterogeneity in time series.

关 键 词：荒漠区 降水脉动 土壤水分 半方差变异函数 

分 类 号：S152.71[农业科学—土壤学]