AnnAGNPS模型参数空间聚合水文效应研究

发布时间：2018-07-05 15:30

本文选题：AnnAGNPS + 日尺度　；参考：《福建师范大学》2015年硕士论文

【摘要】：在全球气候变化和人为活动影响日益增强的背景下,严重的土壤侵蚀造成耕地面积减少、土壤质量退化、水体污染,继而引起一系列的生态和环境问题。分布式水文模型已成为研究变化环境下流域产流产沙演变规律的重要工具。分布式水文模型将流域划分为一定数量的计算单元,以反映流域下垫面特征的空间变化,通过求解这些计算单元来模拟流域水文过程。这些计算单元的分辨率通常大于地形、土壤、土地利用等输入数据的空间分辨率,因此在每个计算单元内的参数值会存在某种程度的集总,即参数的空间聚合。参数的空间聚合程度影响着模型模拟结果,探讨包括地形、土壤、土地利用等输入参数的空间聚合对模拟结果的影响,有助于选择适宜的单元参数聚合值,减少模型的不确定性。山美水库流域位于我国东南沿海泉州市境内,是泉州市重要的水源地。构建流域高精度的日产流产沙分布式水文模型,对于防治流域水土流失、保护流域水资源、促进区域社会经济可持续发展具有重要意义。本文以山美水库流域为研究区,在对AnnAGNPS模型参数敏感性分析的基础上,构建了流域较高精度的日尺度产流产沙AnnAGNPS模型。通过设置9种不同临界源面积(CSA)取值,分析不同分室划分引起的地形、土壤和土地利用的空间聚合效应；并定量分析了参数空间聚合对径流量和输沙量的影响；通过设置7种情景,并进一步定量区分了地形和土壤/土地利用参数的空间聚合对产流产沙过程的影响。结果表明：(1)AnnAGNPS模型能较好的模拟山美水库流域年、月、日尺度产流与产沙过程。(2)随着(CSA)取值增加,流域地形、土壤和土地利用呈现明显的聚合效应。地形参数表现为河网密度、沟道坡度和分室坡度显著降低；土地利用表现为林地面积显著增加,园地、耕地和建设用地面积显著下降；各土壤类型面积变化表现出不同的聚合效应。(3)土壤/土地利用参数空间聚合导致年平均径流量和输沙量减少,且对输沙量影响更显著；地形参数的空间聚合导致年输沙量减少,对年平均径流量无显著影响；土地利用参数空间聚合对径流量和输沙量的影响均大于地形参数的影响。(4)地形参数的空间聚合是影响日径流过程的主要因素,随着聚合程度的增加,日径流过程线呈现洪峰流量增加、峰现时间提前的趋势,且对年平均最大1d径流的影响大于连续最大5d。 (5)土壤／土地利用参数的空间聚合对最大1d输沙量影响较大,随着聚合程度的增加而显著下降,且连续最大5d变化率大于最大1d；而地形参数空间聚合程度的增加造成日输沙过程峰值的出现时间提前。
[Abstract]:Under the background of global climate change and the increasing influence of human activities, serious soil erosion has resulted in the decrease of cultivated land area, soil quality degradation, water pollution and a series of ecological and environmental problems. Distributed hydrological model has become an important tool to study the evolution of runoff and sediment yield in a changing environment. The distributed hydrological model divides the watershed into a certain number of computing units to reflect the spatial variation of the underlying surface characteristics of the basin. The hydrological process of the watershed is simulated by solving these units. The resolution of these units is usually greater than the spatial resolution of the input data such as terrain, soil, land use and so on, so there will be a certain degree of lumped values in each unit, that is, the spatial aggregation of parameters. The degree of spatial aggregation of parameters affects the simulation results. The influence of spatial aggregation of input parameters, such as topography, soil and land use, on the simulation results is discussed, which is helpful to select the appropriate aggregation value of unit parameters. Reduce the uncertainty of the model. The Shanmei Reservoir Basin is located in Quanzhou City, southeast of China, and is an important source of water in Quanzhou City. It is of great significance to construct a high-precision distributed hydrological model of daily runoff and sediment for preventing and controlling soil erosion, protecting water resources and promoting the sustainable development of regional society and economy. Based on the sensitivity analysis of AnnAGNPS model parameters, a high-precision AnnAGNPS model of daily sediment yield in Shanmei reservoir basin was constructed. By setting 9 different critical source area (CSA) values, the spatial aggregation effects of topography, soil and land use caused by different compartments were analyzed, and the effects of parameter spatial aggregation on runoff and sediment transport were analyzed quantitatively. By setting up 7 scenarios, the effects of topography and spatial aggregation of soil / land use parameters on the process of runoff and sediment yield were further quantitatively distinguished. The results are as follows: (1) AnnAGNPS model can well simulate the runoff and sediment yield in the year, month and day of the Shanmei reservoir basin. (2) with the increase of CSA value, the watershed topography, soil and land use show obvious aggregation effect. The landform parameters were the density of river network, the slope of channel and the slope of subdivision, the area of forest land increased significantly, the area of garden land, the area of cultivated land and construction land decreased significantly. (3) the spatial aggregation of soil / land use parameters resulted in the decrease of annual average runoff and sediment transport, and the more significant effect on sediment transport, and the spatial aggregation of topographic parameters led to the decrease of annual sediment transport. The effect of spatial aggregation of land use parameters on runoff and sediment transport is greater than that on topographic parameters. (4) Spatial aggregation of topographic parameters is the main factor affecting daily runoff process. With the increase of polymerization degree, the daily runoff process line showed a trend of increasing Hong Feng flow, and the peak time appeared earlier, and the influence on the annual average maximum runoff of 1 day was greater than that of continuous maximum 5 days. (5) the spatial aggregation of soil / land use parameters had a great influence on the maximum sediment transport in 1 day, and decreased significantly with the increase of aggregation degree, and the maximum change rate of soil / land use parameters for 5 days was greater than that of the maximum one day. The increase of spatial aggregation of topographic parameters makes the peak value of daily sediment transport appear earlier.
【学位授予单位】：福建师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P333

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