Controls on the temporal and spatial variability of soil moisture in a mountainous landscape: the signature of snow and complex terrain
Controls on the temporal and spatial variability of soil moisture in a mountainous landscape: the signature of snow and complex terrain
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DOI：
10.5194/hess-13-1325-2009
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发表时间：
2008-07
影响因子：
6.3
通讯作者：
C. J. Williams;J. McNamara;D. Chandler
中科院分区：
文献类型：
--
作者：
C. J. Williams;J. McNamara;D. Chandler
抽象的。土壤水分空间分布的控制包括静态变量和动态变量。静态和动态控制的叠加可能会导致给定流域在湿润、排水和干燥期间出现不同的土壤湿度模式。在以雪为主的山区，这些关系可能会进一步复杂化，因为降水输入的土壤水很大程度上取决于积雪和融化的空间变化。在本研究中，我们通过评估不同水文季节土壤湿度和场地特征之间的空间相关性，评估对小规模（0.02 km2）、以雪为主的半干旱流域土壤湿度时空变化的控制。我们评估了雪相对于其他流域特性对土壤湿度空间变化的相对重要性，并跟踪这些控制的时间持续性。雪的空间分布、距分水岭的距离、土壤质地和土壤深度对水文年大部分时间水分含量的空间变化具有显着的控制作用。这些关系在最潮湿的时期最强，在干燥的时期减弱。随着流域经历湿润期和干旱期的循环，土壤湿度的相对空间变异性往往保持不变。我们认为，复杂地形（坡度、坡向、土壤）的静态特性对雪的空间变化和由此产生的土壤湿度模式施加一阶控制，并且动态（水输入的时间）和静态影响的相互作用在大部分水文年中传播相对恒定的空间变化。结果表明，雪对中海拔半干旱流域内水的保留方式产生重大影响，并表明与气候变化相关的年度积雪减少可能会强烈影响时空土壤湿度模式以及流域物理和生物过程。
Abstract. The controls on the spatial distribution of soil moisture include static and dynamic variables. The superposition of static and dynamic controls can lead to different soil moisture patterns for a given catchment during wetting, draining, and drying periods. These relationships can be further complicated in snow-dominated mountain regions where soil water input by precipitation is largely dictated by the spatial variability of snow accumulation and melt. In this study, we assess controls on spatial and temporal soil moisture variability in a small (0.02 km2), snow-dominated, semi-arid catchment by evaluating spatial correlations between soil moisture and site characteristics through different hydrologic seasons. We assess the relative importance of snow with respect to other catchment properties on the spatial variability of soil moisture and track the temporal persistence of those controls. Spatial distribution of snow, distance from divide, soil texture, and soil depth exerted significant control on the spatial variability of moisture content throughout most of the hydrologic year. These relationships were strongest during the wettest period and degraded during the dry period. As the catchment cycled through wet and dry periods, the relative spatial variability of soil moisture tended to remain unchanged. We suggest that the static properties in complex terrain (slope, aspect, soils) impose first order controls on the spatial variability of snow and resulting soil moisture patterns, and that the interaction of dynamic (timing of water input) and static influences propagate that relative constant spatial variability through most of the hydrologic year. The results demonstrate that snow exerts significant influence on how water is retained within mid-elevation semi-arid catchments and suggest that reductions in annual snowpacks associated with changing climate regimes may strongly influence spatial and temporal soil moisture patterns and catchment physical and biological processes.