基于SWAT模型的沿渡河流域气候及土地利用变化的水文响应研究

发布时间：2018-05-27 00:09

本文选题：SWAT模型 + 气候变化　；参考：《华中师范大学》2014年硕士论文

【摘要】：本文选取三峡库区沿渡河流域作为研究区域,在遥感技术和地理信息技术的支持下,对现有的气象实测资料和遥感影像进行处理,分析研究区域气候和土地利用／覆被变化的基本特征和规律。对研究流域的土地利用／覆被和土壤类型按照模型数据要求进行重分类和编码,利用近50年的气象观测数据建立适用于研究流域的天气发生器。通过敏感性分析确定敏感性参数,然后采用2001-2005年的径流实测数据与模拟值进行参数校准,2007-2011年的径流实测数据对模拟值进行验证,在此基础上构建了沿渡河流域的SWAT模型。最后采用假定情景方案,主要从水资源管理和利用的角度,模拟研究沿渡河流域气候及土地利用/覆被变化的水文响应。主要研究结果包括以下几个方面： (1)流域气候变化和土地利用/覆被变化的基本特征为：近50年来流域的平均气温呈下降趋势,年平均气温的变化倾向率为-0.003℃/10a；降水的季节分布不均,年际变化呈下降趋势,平均降水的变化倾向率为-5.216mm/10a。流域的土地利用类型以有林地、灌木林地、草地、和耕地为主,共占流域总面积的96%以上,近20多年来,耕地、草地和灌木林地的面积呈减少趋势,而有林地、建设用地的面积均呈增加趋势,土地转移以灌木林地和草地向有林地转入的面积最大。 (2)在ArcGIS软件的支持下,建立模型所需的各种数据库,并划分出79个子流域,生成412个水文响应单元(HURs),进而构建SWAT模型。模型敏感性分析结果表明SCS径流曲线数(CN2)、土壤饱和水力传导系数(SOL_K)、土壤可利用有效水量(SOL_AWC)以及基流alpha系数(ALPHA BF)是对该流域径流影响最显著的参数。采用Ens效率系数、相关系数R2、相对误差Re作为模型模拟的评价标准,校准期三项指标分别为：Ens效率系数=0.71,相关系数R2=0.76,相对误差Re=9.1%,验证期为Ens效率系数=0.62,相关系数R2=0.68,相对误差Re=-14.1%,模拟结果满足模型的精度要求。 (3)假定气候方案模拟分析表明,该流域多年平均流量随气温的上升而减少,温度平均每升高1℃,径流减少0.62%；随降水的增加而增多,降水平均每增加10%,径流增加13.04%；随降水的减少而递减,降水平均每减少10%,径流减少11.28%。年径流变差系数随着气温的上升而增加,但增幅较小,说明径流量的年际波动变化的剧烈程度较小。 (4)假定极端土地利用方案模拟分析表明,有林地涵养水源的效应最强,主要表现为汛期贮积降水,枯水期补给径流,增加流域的可利用水量；另一方面,有林地能在一定程度上减少丰水期的径流量、消减洪峰。有林地同时具备防洪抗旱双重环境生态效应。
[Abstract]:In this paper, the Three Gorges Reservoir Area along the river valley is selected as the research area. Under the support of remote sensing and geographic information technology, the existing meteorological data and remote sensing images are processed, and the basic characteristics and laws of regional climate and land use / cover change are analyzed and studied. According to the requirement of the model data, the weather generator suitable for the study of the basin is established by using the meteorological observation data of the last 50 years. The sensitivity parameters are determined by sensitivity analysis. Then the parameters of the measured data of 2001-2005 years are calibrated with the simulated values, and the measured data of the runoff in 2007-2011 years are entered into the simulated values. On the basis of this, the SWAT model along the river valley is constructed. Finally, the scenario scheme is used to simulate the hydrological response of the climate and land use / cover changes along the river valley, mainly from the perspective of water resources management and utilization. The main results include the following aspects:
(1) the basic characteristics of climate change and land use / cover change in the basin are that the average temperature of the basin has declined in the last 50 years, the change tendency of the annual average temperature is -0.003 C /10a, the seasonal distribution of precipitation is uneven, the interannual change shows a downward trend, and the variation tendency of the average precipitation is the land use type of the -5.216mm/10a. basin. With forest land, shrub forest land, grassland and cultivated land, more than 96% of the total area of the basin was occupied. Over the past 20 years, the area of cultivated land, grassland and shrub land showed a decreasing trend, and the area of the land was increased, and the land transfer area was the largest in shrub land and grassland.
(2) under the support of ArcGIS software, the various databases needed for the model were established, and 79 sub basins were divided into 412 hydrological response units (HURs), and then the SWAT model was constructed. The results of the model sensitivity analysis showed that the number of SCS runoff curves (CN2), soil saturated hydraulic conductivity (SOL_K), available available water (SOL_AWC) and basic flow a The LPHA coefficient (ALPHA BF) is the most significant parameter for the runoff in this basin. Using the Ens efficiency coefficient, the correlation coefficient R2 and the relative error Re as the evaluation criteria for the model simulation, the three indexes of the calibration period are Ens efficiency coefficient =0.71, the correlation coefficient R2=0.76, the relative error Re= 9.1%, the Ens efficiency coefficient =0.62, and the correlation coefficient, The relative error is Re=-14.1%, and the simulation results meet the accuracy requirements of the model.
(3) assuming that the climate scheme simulation analysis shows that the annual average flow rate of the basin decreases with the increase of temperature, the average temperature increases by 1, and the runoff is reduced by 0.62%, with the increase of precipitation, the average precipitation increases by 10% and the runoff increases by 13.04%, with the decrease of precipitation, the decrease of the average precipitation by 10%, and the decrease of the runoff by 11.28%. year path. The difference coefficient increases with the increase of air temperature, but the increase is small, indicating that the interannual fluctuation of runoff is less severe.
(4) it is assumed that the simulation analysis of the extreme land use scheme shows that the effect of the forestland conservation water source is the strongest, mainly in flood season storage and precipitation, recharging runoff during the dry period, and increasing the available water in the basin; on the other hand, the forest land can reduce the runoff in a certain extent and reduce the peak of flood season. Ecological effects of heavy environment.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P332;P343.9

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