Previous studies on semi‐arid ecosystems have shown high values of soil moisture variability (SMV) primarily induced by the combined effects of non‐uniform precipitation, incoming solar radiation, and soil and vegetation properties. However, the relative impact of these various factors on SMV has been difficult to evaluate due to limited availability of field data. In addition, only a limited number of studies have analysed the role of landscape morphology on SMV. Here we use numerical simulations of a simple hydrological model, the Bucket Grassland Model, to systematically analyse the effect of each contributing factor on SMV on two different landscape morphologies. The two different landform morphologies represent landscapes dominated respectively by either diffusive erosion or fluvial erosion processes. We conducted various simulations driven by a stochastically generated 100‐year climate time series, which is long enough to capture climatic fluctuations, in order to understand the effect of various soil moisture controlling factors on the spatiotemporal SMV. Our modelling results show that the fluvial dominated landscapes promote higher spatial SMV than the diffusive dominated ones. Further, the role of landform morphology on SMV is more pronounced in regions where the spatial variability of incoming solar radiation and precipitation is high.

中文翻译：

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景观形态对半干旱生态系统土壤水分变异的影响

先前对半干旱生态系统的研究表明，土壤水分变异性（SMV）的价值很高，这主要是由非均匀降水，入射太阳辐射以及土壤和植被特性的综合影响所致。但是，由于现场数据的可用性有限，很难评估这些各种因素对SMV的相对影响。此外，只有少数研究分析了景观形态对SMV的作用。在这里，我们使用简单的水文模型（桶草地模型）的数值模拟来系统地分析每个因素对SMV对两种不同景观形态的影响。两种不同的地貌形态分别代表了以扩散性侵蚀或河流侵蚀过程为主的景观。我们进行了以随机生成的100年气候时间序列为驱动的各种模拟，该时间序列足够长以捕获气候波动，以了解各种土壤水分控制因素对时空SMV的影响。我们的建模结果表明，与扩散主导的景观相比，河流主导的景观可促进更高的空间SMV。此外，地貌形态在SMV上的作用在入射太阳辐射和降水的空间变异性较高的地区更为明显。我们的建模结果表明，与扩散主导的景观相比，河流主导的景观可促进更高的空间SMV。此外，地貌形态在SMV上的作用在入射太阳辐射和降水的空间变异性较高的地区更为明显。我们的建模结果表明，与扩散主导的景观相比，河流主导的景观可促进更高的空间SMV。此外，地貌形态在SMV上的作用在入射太阳辐射和降水的空间变异性较高的地区更为明显。