黑河流域临泽盐碱化草地网格尺度多层土壤水分时空稳定性分析  

Grid Scale Temporal Stability of Multi-layer Soil Moisture in a Grassland Ecosystem in Western China

作　　者：冉有华[1] 李新[1] 王维真[1] 晋锐[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《地球科学进展》2009年第7期817-824,共8页Advances in Earth Science

基　　金：中国科学院西部行动计划(二期)项目"黑河流域遥感-地面观测同步试验与综合模拟平台建设"(编号:KZCX2-XB2-09);国家重点基础研究发展计划项目"陆表生态环境要素主被动遥感协同反演理论与方法"(编号:2007CB714400)资助

摘　　要：定量分析半干旱环境下盐碱化草地类型土壤水分的时间稳定性,是开展土壤水分尺度时空转换的前提,同时也是水文研究的重要组成部分。基于"黑河遥感—地面同步试验"干旱水文试验区临泽草地加密观测区16个土壤水分剖面的逐日持续观测数据,利用平均相对偏差及相关系数方法,对网格尺度上多层土壤水分的时间稳定性进行了分析。初步表明:①在土壤水分监测点布设上,在相对长的时期内,能代表网络水平上平均土壤水分最优观测的点是存在的,最优观测点位置的选择需要先密后稀,并根据事先的加密观测结果进行稳定性分析,保留平均相对偏差接近于0且其标准差最小的点开展长期观测。②在90 m×90 m的网格尺度上,土壤水分的空间结构在40 cm深度以上各层的时间稳定性是类似的,但稳定程度不同,表层最不稳定。在40 cm以下基本上趋于稳定,空间异质性降低。③研究区所在环境下网格尺度土壤水分空间分布在时间上强烈相关,观测刚开始的几天与其它时期的相关性比较低,在平稳期相关性较好,不稳定性主要由降水或灌溉事件引起。同时,由于环境的复杂性及观测的误差,这种特殊类型土壤水分的时间稳定特征还需要进一步研究。The quantitative study of soil moisture time stability in a semi-arid, grassland types and stalinizaton environmen is an important part of the soil moisture scaling and hydrological studies. This paper .analyzed the time stability of multi-layer soil moisture in grid scale based on the 16 soil moisture profile observation in Linze grassland intensive observation period （IOP） area during ＂ Watershed Airborne Telemetry Experimental Research （WATER） ＂ experimental period using the mean relative difference plot and correlation coefficient method. Results show ： （ 1 ） Soil moisture monitoring points exist, which can represent the grid average value for a relatively long period. The optimal choice of the location of observation points is a thinning process in accordance with prior observations of intensive observation and stability analysis result. （2） In the 90 m ×90 m grid scale, the spatial structure of soil moisture in the depth of upper 40 cm layer is similar, but the degree of stability is different, the surface layer is most unstable. The stability of below 40 cm layer is stabilizing. （3） The spatial pattern is strongly related during WATER period, just started a few days with other days having a low correlation. It has a high positive correlation in the stable phase and high negative correlation in precipitation and irrigation event. Therefore, the instability is mainly caused by rainfall and irrigation. At the same time, due to the complexity of the environment and the observation error, the soil moisture and stability characteristics in the experimental area need further study.

关 键 词：土壤水分 时间稳定性 空间稳定性 遥感 

分 类 号：S152.7[农业科学—土壤学] P941.75[农业科学—农业基础科学]