Research on Spatial Distribution of Settlements in the Upper Reaches of the Minjiang River

Under the background of the uplift of the Qinghai-Tibet Plateau, the settlements in the upper reaches of the Min River are significantly affected by the mountain environment, and their spatial distribution is typical and representative. In this study, the relationship between settlements and topography, rivers and transportation, and the spatial distribution patterns of settlements, such as the aggregation and orientation characteristics of settlements, have been studied. The main conclusions include: 1) The settlement density decreases with the increase of elevation, slope, and distance from rivers and roads;76.25% and 63.17% of the settlements are distributed in the range of elevation 1500 - 3000 m and slope 6° - 25°, the upper reaches of the Min River are mostly alpine valley terrain, the bottom of the river has a low altitude, the landscape is undulating. The warm and humid climate is suitable for farming, conducive to agricultural production, and an ideal living environment for mountain residents. 2) The nuclear density of the settlement is distributed in strips along the axis of the river, and the closer to the river, the greater the nuclear density value. 3) Mathematical statistical methods were applied for the first time to realize the quantitative expression of the coupling of settlement and river direction. The influence of topographic conditions in different watersheds on the coupling degree of settlement extension and river flow direction was revealed. The slope of the fitted straight line between the settlement and river direction was 0.897, and the two directions were consistent. Except for the mainstream of the Min River, the larger values of the standard deviation ellipse flattening of settlements in each basin appeared in the upper reaches of the bay, and the overall trend showed a gradual decrease from the upstream to the downstream, which was consistent with the topographic change characteristics of the basin.

Assessment of land use change and potential eco-service value in the upper reaches of Minjiang River,China

The remote sensing （RS） and geographical information system （GIS） technologies were adopted and a mathematic method was developed to evaluate the changes of ecosystem services in the upper reaches of Minjiang River-valley for providing advices to manage the ecosystem. The results showed that the land use change mainly occurred on forest, farmland and grassland. From 1986 to 1994, the area of farmland increased by 477% （60801 hm^2）, while the area of forest decreased by 4.97% （89012.17 hm^2）. From 1986 to 2000, the eco-service value of forest was degressive but that of farmland increased greatly as the increasing of planting area, while the total eco-service value decreased by 771.11×10^8 yuan RMB due to the rapid increase of population in this region. The driving force of eco-service change was also discussed in the paper. The nation policy of Natural Forest Protection Project has taken effect in preventing the decline of eco-services.

Unsteadiness of COD in the Upper and Middle Reaches of Minjiang River

This paper explores and identifies the rules of the unsteady evolution of COD in the upper and middle reaches of Minjiang River through multi-scale analysis on the weekly COD data for the last six years provided by the Water Quality Monitoring Station,Minjiang River Bridge,Leshan City,Sichuan Province.The results of the wavelet analysis indicate that the COD index oscillates alternatively and differently at each time-scale in an oneyear cycle,and the density of COD,subjected to the runoff volume,the effects of Wenchuan Earthquake and agricultural seeding and industrial construction,etc.,is high in winter and spring,mild in summer and autumn.

Risk Assessment of Highway in the Upper Reaches of Minjiang River under the Stress of Debris Flow

The southwest mountainous area is a frequent debris flow disaster area in China, which poses a serious threat to the regional roads and greatly affects the normal traffic operation and the safety of residents’ lives and property. The debris flow risk assessment of highway can quantify the threat degree of debris flow to the roads. In this paper, from the perspective of villages and towns, taking the upper reaches of Minjiang River as the research area, four factors including road network density, highway disaster resistance capacity, population density and highway cost are selected, and the weight is obtained by using entropy weight method, and the debris flow vulnerability evaluation results of highway are obtained by weighted calculation. Four indexes of debris flow density, shape factor, relative height difference and annual rainfall are selected to evaluate the debris flow hazard of highway by using the information method. Based on the vulnerability and hazard evaluation results, the risk of highway debris flow is evaluated, and the results are classified and discussed. The results show that: the risk of debris flow on the upper reaches of Minjiang River is relatively low, the overall spatial distribution shows a trend of high in the East and low in the west, and the overall risk of township roads in Wenchuan county is the highest;The risk of debris flow is generally high within -10 to 30 km from the central fault zone of Longmenshan.

Based on the Theory of Optimizing the Allocation of Research of Sustainable Utilization of Water Resources of the Upper Reaches of Minjiang River

Water resource is an important supporting material for life support system and economic development, and the sustainable development and utilization of water resource are the guarantee of social sustainable development. The upper Minjiang River is the most important source of water supply for the Chengdu Plain. With the water resources of the upper Minjiang River facing the problems of overall water volume reduction, flood and water pollution, etc., based on the optimal allocation theory, this paper constructs an optimal allocation model of water resources in the upper reaches of the Minjiang River, analyzes its characteristics and proposes some relevant countermeasures and suggestions to solve the existing problems, aiming to provide references for the sustainable utilization of water resources in the upper reaches of the Minjiang River.

Assessing the Impact of the Sloping Land Conversion Program on Rural Household Income in the Upper Reaches of Minjiang River,China

One secondary target of the SLCP is poverty reduction. Therefore,the impact of the SLCP on household income is a subject of much research. This study was conducted to determine whether the SLCP has affected incomes of households at different income levels13 years after its implementation. Using survey data from 2012 on rural households＇ livelihoods in the upper reaches of the Minjiang River in Sichuan Province and using the non-participating households as a reference,the current impact of the SLCP on household income is calculated with a multiple linear regression model and a quantile regression model. The socio-geographic features of participating and non-participating households are also be compared. The results show no significant differences between the SLCP participating and non-participating households in many socio-demographic characteristics. Participating in the SLCP had no significant impact on household income at all income levels in the study area in 2012. This finding suggests that the SLCP is not currently increasing household income significantly in the study area,and that the implementation plan of the SLCP should be changed in this area in order to achieve its poverty reduction goal.

岷江上游汶川地震前后泥石流易发性评价

科学准确地绘制泥石流易发性区划图以及确定主控因子及其贡献率,是区域泥石流预警预报和风险管理的重要基础。文章以岷江上游为研究区,以小流域为评价单元,分别采用了5种机器学习模型构建了泥石流易发性评价模型,对汶川大地震前、后岷江上游泥石流易发性和评价因子贡献率进行了定量分析。结果表明:(1)集成机器学习模型的预测精度及受试者工作特征曲线下面积值均高于浅层机器学习模型,其中随机森林模型在地震前、后泥石流易发性评价中表现最优;(2)震前、震后泥石流发生率均随易发性等级的提高逐渐增大,且等级越高增量越大,各等级震后泥石流发生率均高于震前;(3)地震前、后侵蚀传递系数的贡献率均显著高于其他因子,与汶川大地震地震烈度空间分布特征叠加,加大了震后干流和支流泥石流由下游向上游发育程度逐渐降低的空间分布规律。

岷江上游1995—2020年生态地质环境安全评价与时空演化分析

岷江上游是长江上游生态安全的重要屏障,在“5·12”汶川地震发生后,地下岩体、地表基质和地上生态都受到了严重的破坏。为探索岷江上游流域地震前后生态地质环境安全状况,从“地质环境-生态环境”两个维度选取了16个评价指标,基于AHP-PCA熵组合权重法对岷江上游流域1995年、2001年、2009年和2020年生态地质环境安全进行评价并分析演化趋势。结果表明:岷江上游流域生态地质环境安全整体以较安全-安全为主。其中,生态地质环境较安全-安全主要分布在流域的中、东部地区,较不安全-不安全主要分布在西、北部高山区以及深切河谷区,整体呈现中东部高、西部和北部低的格局。1995—2020年岷江上游生态地质环境安全整体呈现先降低后逐步升高的趋势。其中,流域北部及深切河谷区生态地质环境安全变化波动大,且呈现升高-降低-升高的趋势,生态地质环境不稳定;西南部生态地质环境安全整体以降低为主,虽降低区域逐渐减少,但总体生态地质环境仍持续变差;流域中部生态地质环境安全整体以升高为主,且升高区域逐渐增加,生态地质环境持续向好。本次研究结果可为岷江上游生态保护修复提供基础支撑。

岷江上游近59年径流变化及归因识别

为高效利用岷江上游流域的水资源,基于1960~2018年流域水文气象资料,采用多种统计学理论分析径流的趋势、周期和突变点,应用基于Budyko理论的弹性系数法(Choudhury-Yang公式)和累积量斜率变化率比较法(SCRCQ法)对径流变化进行归因分析。结果表明,径流以12.5mm/10a的速率呈显著减少趋势,并在1993年发生突变。径流变化存在3、8、12、18年的主周期,其年内分配不均,主要集中于夏秋两季,占比73.6%。降雨对径流变化最为敏感,下垫面参数次之,潜在蒸散发最不敏感。Choudhury-Yang公式和SCRCQ法计算出气候变化对径流减少的贡献率分别达到58.13%、63.29%,表明气候变化是研究区径流减少的主要因素,而人类活动对径流减少的贡献亦不容低估,贡献率分别达到41.87%、36.71%。

岷江上游芦花地区传统藏族民居建筑特征探析

芦花地区地处我国藏羌民族聚居的交错地带,其地域民族文化中杂有周边文化成分,显现出与藏彝走廊其他区域不同的民族文化特点,这种文化属性使得地域民居的文化事象和建筑特征也更有特色。研究以芦花地区传统藏族民居为对象,以建筑学、民族学与文化生态学的综合视角,运用田野调查、实地测绘、文献爬梳和口述访谈等方法,分析地缘环境与民族文化融合背景下民居的建筑特征以及文化生态,归纳民居建筑形体、空间构成、材料构造、建筑装饰方面的主要特征,为传统藏族民居的保护和利用提供依据。

岷江上游面雨量多模式预报检验与集成研究

基于三源融合格点实况降水资料,以岷江上游面雨量为研究对象,采用多种评估指标,对2019年4月—2021年12月SWCWARMS、ECMWF、GRAPES_MESO模式及四川省智能网格的面雨量预报效果进行检验评估,并在此基础上采用回归集成、TS集成和Nash系数集成等方法开展了面雨量集成预报研究。结果表明:智能网格和ECMWF在岷江上游面雨量预报中的效果较优。面雨量分级检验中,4种单模式预报的TS评分随着量级增大而逐渐降低,空报率和漏报率逐渐增大,ECMWF在小雨预报中效果最好,智能网格在中雨预报中优于其他模式,SWCWARMS在大雨预报中占优。面雨量集成预报能较好地提升预测效果,3种多模式集成方法对比,回归集成的误差更小,而AS评分和效率系数更高。面雨量分级预报中,小雨预报宜采用3个模式多元回归集成,中雨预报宜采用4个模式TS集成,而大雨预报应考虑3个模式TS集成。

岷江上游羌族传统村寨人居环境营造特色解析——以老木卡寨为例

羌族是我国最古老的民族之一,主要聚居在四川省境内岷江上游一带。岷江上游水网密集、山峦更迭的生态背景,多元的民族文化背景,影响着羌族传统村寨人居环境的营造特色。将传统羌族村寨的人居环境分为生态格局、支撑系统与民居单元三项基本内容,归纳出传统羌族村寨“山-林-水-寨-地”的人居环境生态格局特征、支撑系统的防御性特征与民居单元的山地性特征。以四川省理县老木卡河谷羌寨为例,进一步从村寨布局与民居建筑等多方面具体阐述羌族传统村寨人居环境营造的生态特色、防御特色与山地特色,为传统羌族村寨的保护与修复提供新的思路。

岷江上游地区人类活动强度及其特征

利用1∶25万国家基础地理信息数据,在ArcGIS支持下,基于地理学自相关理论,采用居民点、道路和地形因子等权重指标,实现岷江上游人类活动强度定量化的空间表达,并分析其空间特征。结果表明:岷江流域各个县域人类活动强度大小和分布均有差异,其中黑水县人类活动最为剧烈,且分布最为均匀;理县和茂县人类活动强度和分布均匀程度基本接近全流域的平均水平;靠近成都平原的汶川县,因卧龙保护区位于该区境内,使该县的人类强度降低,同时其人类活动的空间分布亦不均匀;松潘县地处北部,人类活动强度最低。本研究采用坡度、道路和居民点3个因子来定量化人类活动强度,反映了研究区人类活动强度及其空间分布特征,从而为进一步探讨景观格局演变提供了新的思路。

GIS支持下岷江上游土壤侵蚀动态研究

利用TM数据,采用3S技术和通用土壤侵蚀方程(RUSLE)研究岷江上游地区3个典型时期的土壤侵蚀动态,并对影响侵蚀的主要因子进行初步分析.结果表明,研究区3个时期侵蚀面积分别占研究区总面积的1.28%、1.84%和1.70%;年平均侵蚀模数分别为832.64、1048.74和1362.11t.km-2,以微度侵蚀、轻度侵蚀为主,伴有少量的中度侵蚀.侵蚀面积比较小,侵蚀程度比较轻.侵蚀与坡度呈显著正相关,侵蚀大多发生在>25°的区域,1986年占总侵蚀量的93.65%,1995年为93.81%,2000年为92.71%;在海拔上,中山、亚高山、高山以及干旱河谷是侵蚀发生的主要地带,1986年占总侵蚀量的98.21%,1995年为97.63%,2000年为99.27%;不同类型的植被直接影响到侵蚀的发生,灌木林地以及新退耕的疏林地是3个时期侵蚀的主要发生地,过度放牧导致草场退化,也产生了微度侵蚀;侵蚀的发生和土壤类型密切相关,燥褐土、石灰性褐土最易发生侵蚀,是控制侵蚀的重点区域;人口的增长、户数的增加是侵蚀发生的驱动因子,人口与户数增长导致资源需求压力的增大,侵蚀呈线性增加.

土地利用模型时间尺度预测能力分析——以CLUE-S模型为例

模型模拟是生态学中的重要方法,特别是当实验不可进行时。在不同预案下基于模型的土地利用预测对于土地利用规划和政策制定具有十分重要意义。然而,很多研究没有对模型在研究区的时间尺度预测能力加以分析,从而可能导致模拟结果的不可靠。以岷江上游地区为例,采用Kappa指数系列对CLUE-S模型在研究区的时间尺度预测能力进行研究。结果表明CLUE-S模型在岷江上游地区时间尺度上的最大预测能力为22a,超过时间预测能力的预测结果不可靠。研究为土地利用模型模拟时间尺度确定提供了一种有效的方法。

岷江上游辽东栎天然次生林生物量测定

通过对岷江上游理县境内辽东栎(Quercusliaotungensis)天然次生林生物量和生产力测定与研究,结果表明:辽东栎天然次生林生物量为488.49t/hm2,其中乔木层生物量占绝对优势,达林分总生物量的99.22%,其余依次为枯枝落叶层、灌木层、苔藓层和草本层;乔木层中各器官生物量由大至小排序为:树干材、树枝、树根、树皮、树叶、果实;不同根系部位生物量由大至小为:根桩、粗根、中根、细根。灌木层不同部位生物量由大至小为:根、干枝、叶,草本层根的生物量大于地上部分生物量,枯枝落叶层的生物量大小依次表现为落叶、枯枝、落果。

岷江上游地区近30年森林生态系统水源涵养量与价值变化

根据岷江上游地区自然地理环境条件的差别,将该区森林植被划分为暗针叶林、其它针叶林、阔叶林和灌木林等4个类型,利用年降雨量、林冠截流量数据、径流系数以及“影子价格”等方法,计算和评述了该区森林生态系统水源涵养效益;并利用遥感4期影像分析了岷江上游地区森林生态系统水源涵养量的变化原因。结果表明:2000年岷江上游森林生态系统年水源涵养量最高,为1·3892×1010m3,经济价值为93·07亿元。去除降雨量的影响后,在各时期年降雨量为705mm的情况下,岷江上游地区1986年的水源涵养量最高,为1·3348×1010m3,经济价值为89·43亿元;1995年水源涵养量下降,为1·2320×1010m3,经济价值为82·54亿元;2000年水源涵养量及经济价值与1995年基本持平。造成这一现象的主要原因是20世纪90年代岷江上游森林景观受到人为的严重破坏,而随后实施的“天然林保护工程”与“退耕还林还草”政策,加强了人工植被恢复建设,改善了森林生态系统,使森林生态系统水源涵养量有所恢复。

岷江上游生态脆弱性评价

岷江上游流域是我国典型的生态脆弱区之一 ,由于地质变化频繁、高差显著、气候干旱 ,加上人为活动影响 ,生态脆弱性的表现十分明显。通过对其生态环境脆弱性因素及成因机制的分析 ,构建了由土地生产力、地表起伏度、干燥度指数、土壤侵蚀强度、草场退化荒漠化率、物种消失率等 14个指标组成的岷江上游生态脆弱性的评价指标体系 ;根据本地区生态环境现状、全国和四川省情况及奋斗目标 ,建立了Ⅰ到Ⅲ级的评价标准体系 ;利用模糊数学聚类方法对评价指标进行分析计算 ,得出了岷江上游生态环境为第Ⅲ级 ,即生态环境非常脆弱的结论。评价结果符合岷江上游地区的生态环境状况。

岷江上游干旱河谷景观变化及驱动力分析

基于遥感和地理信息系统,应用景观格局分析软件,研究了岷江上游干旱河谷1974—2000年的景观变化,并对其驱动因子进行了分析。结果表明,岷江上游干旱河谷的面积在不断扩大,灌木林地面积占景观面积的60%以上,为景观基质。在景观类型面积比例的变化中,耕地的变幅最大。干旱河谷的整体形状较简单,1974—1995年破碎化程度和异质性程度持续增加,1995—2000年表现为降低趋势,而斑块内部的连通性先降低后增加,具体表现为斑块密度、多样性指数先增大后减小,蔓延度指数先减小后增大,而边界密度和分维数持续减小。人口增长和国家政策是导致岷江上游干旱河谷景观变化的主要驱动力。

岷江上游典型时期景观格局变化及驱动力初步分析

岷江上游地区是我国一个重要的大尺度、复合型生态过渡带 ,也是一个生态系统脆弱区 ,研究其景观格局的变化 ,对于构筑我国的生态格局安全具有十分重要的意义 .本研究利用岷江上游地区 1986、1995、2 0 0 0年 3个时期的TM影像 ,分析了 3个时期的景观特征以及变化 .结果表明 ,岷江上游整体景观水平以草地景观为基质、森林景观以及其他景观类型作为斑块镶嵌其中 .森林景观面积经历了从 1986～1995年的上升 ,而后到 2 0 0 0年的下降过程 ;草地景观高盖度草面积不断减少 ;同时 ,森林景观和草地景观斑块总数一直增加 ,破碎化趋势明显 .岷江上游景观格局变化的驱动因子主要是日益增加的人口数量而导致的人为干扰 ,包括对土地利用方式与利用强度的改变、森林资源的掠夺性开采、草地资源的过度放牧以及气候、土壤等自然因素的变化 .