【作者】 王冰；

【导师】 牛健植；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2021， 硕士

【摘要】 气候变化和以土地利用变化为主导的人类活动对河流水沙量的影响的研究,对流域水土资源的合理利用和保护以及水土保持工程有着重要的意义和价值。本文以张家口崇礼区东沟流域为研究区,采用累积距平法、Mann-kendall非参数检验法、滑动平均法、Morlet分析法、双累积曲线法,研究分析张家口东沟流域2006-2018年(即冬奥会项目工程开展前后时期)降水量以及水沙量的变化特征和长期的变化趋势;利用ENVI软件的监督分类功能对东沟流域进行土地利用类型的划分,并结合Arc GIS技术、Fragestats软件获得东沟流域2006-2018年的土地利用变化指标(包括土地利用转移矩阵、单一土地利用动态度、综合土地利用动态度)、景观格局变化指标,分析该时期研究区的土地利用变化以及景观格局时空变化过程与特征;基于双累积曲线法和回归分析法,研究降水量等气候变化和包括土地利用变化为在内的人类活动对流域内水沙变化的贡献率。主要研究结论如下:(1)东沟流域降水变化:东沟流域的年均降水量、汛期降水量、夏季降水、秋季降水以及日降水指标(最大日降水和连续七日最大降水)均呈现不显著的上升趋势,春季与冬季降水为下降趋势。年降水量、汛期降水量、夏季降水、秋季降水等降水指标在2013-2018年为丰水期,冬季降水在2007-2018年表现为丰水期。除春季降水量、秋季降水量没有突变点之外,其他降水量指标的突变点都在2011-2013年。年降水量存在两个明显的周期,峰值分别为2a和7a,表明年降水量的变化以小尺度为主进行周期性震荡。(2)东沟流域土地利用及景观格局变化:2006年以来,东沟流域的土地利用类型以林地、耕地、灌木/草地为主,三者面积之和在2006年、2010年、2014年、2018年占比分别为84.43%、92.62%、94.99%、96.02%。自2006以来,林地的大部分面积未发生改变。2006-2010年,土地利用动态度高,各地类之间的互相转化比较多,2010-2018年,各土地利用类型面积变化比较小,综合土地利用动态度仅为前期的1/2。东沟流域的城乡建设用地、农耕地和水域主要分布在平坡和缓坡阳坡区域,林地、灌木/草地主要分布在斜坡、陡坡等区域,并且多在阳坡环境下。水域、城乡和建设用地、林地、耕地整体都表现为景观异质性程度下降,景观破碎化程度减小,连通性好的变化趋势,而由于人为因素的影响,灌木/草地斑块的景观破碎度增大,斑块间连接性变差。(3)东沟流域水沙变化:2006-2018年东沟流域的径流量表现为轻微上升的趋势,而输沙量表现为明显的下降趋势,流域水沙的年际变化比较大。2006-2014年,流域内径流量比较充沛,2014年之后径流量处于枯水期,而2006-2008年为流域的多沙期,2009-2018年为少沙期。2013年,流域径流量表现为由少增多的突变趋势,同期的输沙量经验证不存在突变点。另外,流域内水沙量周期性变化分析结果表明:径流量存在两个周期,其中6a的时间尺度为径流量周期性最强的尺度,输沙量周期性变化的尺度为16a,周期远大于径流量的变化周期。(4)东沟流域降水量和土地利用格局指数与水沙的相关关系:流域的年径流量、年输沙量与降水量、土地利用类型面积的相关关系未达到显著水平(P>0.05);流域的径流与景观格局指数的相关性未达到显著性,而NP、PD指数与输沙量成正相关关系,而AI与输沙量成负相关关系。(5)东沟流域降水量和土地利用变化对水沙的影响评价:降水量与流域水沙的双累计分析表明,年降水量等降水条件是影响东沟流域2006-2018年水沙变化的主要原因。以2006-2009年为基准期得到,2010-2014年土地利用等人类活动对径流、输沙量的贡献率分别为56.46%、67.81%,年降水量对二者的贡献率分别为43.54%、32.19%。2015-2018年土地利用变化等人类活动对流域水沙变化的贡献率分别为33.56%、80.04%,年降水量对二者的贡献率分别为66.44%、19.96%。更多还原

【Abstract】 The study on the effects of climate change and human activities on the runoff and sediment of rivers is of great significance and value to the rational utilization and protection of water and soil resources and water and soil conservation projects in the river basin.Taking Donggou watershed in Chongli District of Zhangjiakou as the study area,this paper used cumulative anomaly method,Mann-Kendall non-parametric test method,moving average method,Morlet analysis method and double accumulation curve method to analyze the change characteristics of precipitation,runoff and sediment discharge and their future change trend during 2006-2018.The classification function of ENVI software was used to classify the land use types in Donggou watershed,and the land use transfer matrix,single and comprehensive land use dynamic degree and of Donggou watershed from 2006 to 2018 were obtained by combining with Arc GIS technology and Fragestats soft to explore the spatio-temporal change process and characteristics of land use and landscape pattern.Based on the double accumulation curve method and regression analysis method,the contribution rates of climate change such as precipitation and human activities including land use change to water and sediment change in the basin were studied.The main research conclusions are as follows:(1)Precipitation change: The annual average rainfall,flood season precipitation,summer precipitation,autumn precipitation and precipitation index of day(maximum daily precipitation and seven consecutive days maximum precipitation)of Donggou watershed are present the rising trend but not significant,the spring and winter precipitation showed the downward trend;The annual rainfall,flood season precipitation and summer precipitation,autumn precipitation index were plentiful from2013 to 2018,however the winter precipitation was plentiful in 2007-2018;Except for spring precipitation and autumn precipitation,which have no sudden change point,the sudden change points of other precipitation indexes are all from 2011 to 2013;There are two obvious cycles of annual precipitation,and the peak value is 2a and 7a,respectively,indicating that the annual precipitation changes are mainly periodic oscillations in small scales.(2)Land use change in Donggou watershed: Since 2006,the land use types in Donggou Basin are mainly forest land,cultivated land and shrub/grassland,and the total area of the three types in 2006,2010,2014 and 2018 accounts for 84.43%,92.62%,94.99% and 96.02%,respectively.Most of the forest land has not changed since 2006.From 2006 to 2010,the dynamic degree of land use was high,and there was a lot of mutual transformation among different land use types.From 2010 to 2018,the area change of each land use type was relatively small,and the dynamic degree of comprehensive land use was only half of that in duration of 2006-2010;.In Donggou watershed,urban and rural construction land,agricultural land and water area are mainly distributed in flat slope(0°-5°)and gentle slope(5°-15°)sunny slope area,while forest land,shrub/grassland are mainly distributed in incline(15°-25°)and steep slope(>25°)area,and most of them are in sunny slope having better hydrothermal conditions.Water area,urban and construction land,forest land and cultivated land all showed a trend of decreasing landscape heterogeneity,decreasing landscape fragmentation and good connectivity.However,due to the influence of human factors,the landscape fragmentation degree of shrub/grassland patches increased and the connectivity between patches became worse.(3)Variation of water and sediment in Donggou watershed: From 2006 to 2018,the runoff of Donggou watershed showed a slight upward trend,while the sediment discharge showed an obvious downward trend,and the inter-annual variation of runoff and sediment in the basin was relatively large.From 2006 to 2014,the runoff in the watershed was abundant,and after 2014,the runoff was in a dry period.From 2006 to 2008,the sediment was in a high-sand period,and from 2009 to 2018,the sediment was in a low-sand period.2013 is the abrupt change point of runoff from less to more,and there is no abrupt change point of sediment discharge in the same period.The results of periodic variation of runoff and sediment show that there are two cycles in the runoff,of which the time scale of6 a is the most periodic scale of runoff,and the scale of the periodic change of sediment discharge is 16 a,and the cycle is much larger than that of runoff.(4)The correlation between precipitation,land use pattern index and water and sediment in Donggou Basin : The correlation between annual runoff,annual sediment transport and precipitation、land use type area was not significant(P>0.05);The correlation between runoff and landscape pattern index is not significant,while NP and PD index are positively correlated with sediment discharge,while AI is negatively correlated with sediment discharge.(5)Impact assessment of precipitation and land use change on runoff and sediment: The dual cumulative analysis of precipitation and runoff and sediment in the Donggou watershed shows that human activities such as land use change are the main reasons for water and sediment change in the Donggou Basin from 2006 to 2018.Taking 2006-2009 as the base period,the contribution rates of human activities such as land use to runoff and sediment discharge from 2010 to 2014 are 56.46% and67.81%,respectively,and the contribution rates of annual precipitation to runoff and sediment discharge are 43.54% and 32.19%,respectively.From 2015 to 2018,the contribution rates of human activities such as land use to runoff and sediment transport were 33.56% and 80.04%,respectively,and the contribution rates of annual precipitation to runoff and sediment transport were 66.44% and 19.96%,respectively.更多还原