土壤水分运动参数的空间变异与传递函数研究

发布时间：2018-03-06 16:00

本文选题：土壤水分特征曲线　切入点：土壤水分扩散率　出处：《西北农林科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：土壤水分运动参数是土壤水分运移研究的重要因素之一,水分运动参数的空间变异性也受到了重视与关注。本论文利用经典统计学方法、多重分形方法、联合多重分形方法和土壤传递函数,以杨凌及其周边地区为例,在试验的基础上建立了区域尺度上0-20cm土层和20-40cm土层土壤水分特征曲线的单一参数模型、非饱和土壤水分扩散率的单一参数模型,研究分析了不同土层单一参数模型中参数在单一尺度和多尺度上的空间变异性,探讨了上下不同土层的单一参数模型中参数之间在多尺度上空间变异性的相互关系,同时对不同土层单一参数模型中参数与土壤物理特性在多尺度上的相互关系进行了探讨,并基于此构建了区域尺度上0-20cm土层和20-40cm土层单一参数模型中参数的土壤传递函数。主要得出以下结论:(1)基于经典统计学方法、多重分形和联合多重分形分析可知,构建的杨凌及其周边地区0-20cm土层和20-40cm土层的土壤水分特征曲线单一参数模型中参数F具有中等变异程度;不同土层参数F的多重分形特征明显,0-20cm土层参数F空间变异性主要是由其低值引起的,20-40cm土层参数F空间变异性主要是由其高值分布引起的;0-20cm土层参数F与20-40cm土层参数F在多尺度上具有较高的相关程度或某些相同的空间分布。(2)基于单对数模型建立的杨凌及其周边地区0-20cm土层和20-40cm土层非饱和土壤水分扩散率的单一参数模型中参数S都属于中等变异程度;多重分形方法分析结果表明不同土层参数S的空间分布格局的多重分形特征比较明显,且空间变异性都主要是由高值分布引起的;联合多重分形方法分析结果显示,0-20cm土层参数S的空间变异性与20-40cm土层参数S的空间变异性之间的相互关系在多尺度上是显著存在的。(3)单一尺度与多尺度空间相关性分析对比可知,0-20cm土层、20-40cm土层单一参数模型中参数与影响因素之间的空间相关特征在单一尺度和多尺度上并不完全相同,说明单一尺度上的分析不一定能够完整地揭示出单一参数模型中参数与影响因素之间的空间相关特性。因此,为了更加深入的揭示造成不同土层单一参数模型中参数空间变异性的因素,应当加强不同土层单一参数模型中参数与影响因素在多尺度上空间相关性的分析研究。(4)根据联合多重分形研究分析所得结论分别建立了区域尺度上0-20cm土层和20-40cm土层土壤水分特征曲线单一参数模型中参数F的土壤传递函数、土壤水分扩散率单一参数模型中参数S的土壤传递函数。其中0-20cm土层和20-40cm土层参数F的土壤传递函数预测值的RMSE分别为0.9684和0.6230,0-20cm土层和20-40cm土层参数S的土壤传递函数预测值的RMSE分别为0.3569和0.4925,所建土壤传递函数的预测值与实测值都比较接近,为较大区域土壤水分特征曲线和土壤水分扩散率的估算提供参考。
[Abstract]:The parameters of soil moisture movement are one of the important factors in the study of soil moisture migration, and the spatial variability of soil water movement parameters has also been paid attention to. In this paper, the classical statistical method and multifractal method are used. Combined with multifractal method and soil transfer function, taking Yang Ling and its surrounding area as examples, a single parameter model of soil moisture characteristic curve of 0-20cm soil layer and 20-40cm soil layer on regional scale was established on the basis of experiments. The single parameter model of unsaturated soil water diffusivity is studied and the spatial variability of parameters in single parameter model of different soil layers on single scale and multi scale is studied. The relationship between the spatial variability of the parameters in the single parameter model of different soil layers on multiple scales and the relationship between the parameters and the soil physical characteristics in the single parameter model of different soil layers on multiple scales are discussed. Based on this, the soil transfer function of 0-20cm soil layer and 20-40cm soil layer single parameter model is constructed. The main conclusions are as follows: (1) based on the classical statistical method, multifractal and joint multifractal analysis, we can know that, In the single parameter model of soil moisture characteristic curve constructed by Yang Ling and its surrounding areas in 0-20cm and 20-40cm soil layers, the parameter F has a moderate degree of variation. The multifractal characteristics of different soil layer parameters F are obvious. The spatial variability of 0-20cm soil layer parameter F is mainly caused by its low value and the spatial variability of its 20-40cm soil layer parameter F is mainly caused by its high value distribution of 0-20cm soil layer parameter F and 20-40cm soil layer parameter F and 20-40cm soil layer. Parameter F has higher correlation degree or some same spatial distribution on multi-scale.) based on the single logarithmic model, a single parameter model of unsaturated soil water diffusivity of 0-20cm soil layer and 20-40cm soil layer in Yang Ling and its surrounding area is established. The middle parameter S belongs to the moderate degree of variation. The results of multifractal analysis show that the multifractal characteristics of the spatial distribution pattern of different soil parameters S are obvious, and the spatial variability is mainly caused by the high value distribution. The results of joint multifractal analysis show that the spatial variability of 0-20cm soil layer parameter S and the spatial variability of 20-40cm soil layer parameter S are significant in multi-scale. The characteristics of spatial correlation between the parameters and the influencing factors in the single parameter model of 0-20cm soil layer 20-40cm soil layer are not identical in single scale and multi-scale. It shows that the analysis on a single scale does not necessarily reveal the spatial correlation between the parameters and the influencing factors in a single parameter model. In order to reveal the factors that cause the spatial variability of parameters in the single parameter model of different soil layers, The spatial correlation between parameters and influencing factors in single parameter model of different soil layers should be strengthened. (4) based on the conclusion of joint multifractal analysis, 0-20cm soil layer and 20-40cm soil layer on regional scale are established respectively. The soil transfer function of parameter F in a single parameter model of soil moisture characteristic curve, The soil transfer function of parameter S in a single parameter model of soil moisture diffusivity, in which the RMSE of the predicted values of soil transfer function for 0-20cm soil layer and 20-40cm soil layer parameter F is 0.9684 and 0.62300-20cm soil layer and 20-40cm soil layer parameter S respectively. The RMSE of the predicted values were 0.3569 and 0.4925, respectively. The predicted values of the soil transfer function were close to the measured values. It provides a reference for the estimation of soil moisture characteristic curve and soil water diffusivity in larger area.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7

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