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1.
According to differences in vegetation types and their coverage,combining the latest research ,using theory and method on the value of vegetation ecosystem services ,this paper not only calculated goods produced by different types of vegetation but also estimated the value of various vegetation ecosystem services and set up database,GIS and eco-account of vegetation ecosystem.The result was as follows: the value of vegetation‘‘s primary productivity,soil and fertility conservation,water conservation.CO2 fixation and O2 release was 199.6 billion yuan/a 22.64 billion yuan/a 22.6 billion yuan/a ,352.24 billion yuan/a and 374.19 billion yuan/a ,respectively.The total value of ecosystem services was 968.33 billion yuan/a.The temperate deciduous broad-leaved forest had the highest contribution rate,accounting for 16.42%,The result of value can reflect regional reality more exactly.  相似文献   

2.
The question of how to generate maximum socio-economic benefits while at the same time minimizing input from urban land resources lies at the core of regional ecological civilization construction.We apply stochastic frontier analysis(SFA)in this study to municipal input-output data for the period between 2005 and 2014 to evaluate the urbanization efficiency of 110 cities within the Yangtze River Economic Belt(YREB)and then further assess the spatial association characteristics of these values.The results of this study initially reveal that the urbanization efficiency of the YREB increased from 0.34 to 0.53 between 2005 and2014,a significant growth at a cumulative rate of 54.07%.Data show that the efficiency growth rate of cities within the upper reaches of the Yangtze River has been faster than that of their counterparts in the middle and lower reaches,and that there is also a great deal of additional potential for growth in urbanization efficiency across the whole area.Secondly,results show that urbanization efficiency conforms to a"bar-like"distribution across the whole area,gradually decreasing from the east to the west.This trend highlights great intra-provincial differences,but also striking inter-provincial variation within the upper,middle,and lower reaches of the Yangtze River.The total urbanization efficiency of cities within the lower reaches of the river has been the highest,followed successively by those within the middle and upper reaches.Finally,values for Moran’s I within this area remained higher than zero over the study period and have increased annually;this result indicates a positive spatial correlation between the urbanization efficiency of cities and annual increments in agglomeration level.Our use of the local indicators of spatial association(LISA)statistic has enabled us to quantify characteristics of"small agglomeration and large dispersion".Thus,"high-high" (H-H)agglomeration areas can be seen to have spread outwards from around Zhejiang Province and the city of Shanghai,while areas characterized by"low-low"(L-L)patterns are mainly concentrated in the north of Anhui Province and in Sichuan Province.The framework and results of this research are of considerable significance to our understanding of both land use sustainability and balanced development.  相似文献   

3.
Understanding the value of ecosystem services is useful for the decision making and sustainable management of the wetlands. It would be better to integrate ecological, economic and social factors into ecosystem service valuation. The general value of the Zoigê Wetland Nature Reserve in the southwest China by integrating a social welfare weight, which is determined by a three-level analytic hierarchy process, was calculated. Through analyzing the functions, stakeholders and ecosystem services of the Zoigê Wetland Nature Reserve, the six main services, including substance production, flood control, gas regulation, climate regulation, recreation, and biodiversity conservation,were selected; and a three-level hierarchical structure model was established. The top(goal) level of the model refers to the total ecosystem services value of the Zoigê Wetland Nature Reserve, the middle level(stakeholder level) refers to stakeholders at different scales, and the bottom level(service level) refers to individual services provided by the Zoigê Wetland Nature Reserve. The results indicated that the ecosystem services value of the Zoigê Wetland Nature Reserve was 320.38×10~8yuan RMB in 2011. If including the social welfare, the value increased to 2258.68×10~8yuan RMB. The value of biodiversity conservation accounted for the largest proportion, which were 53% without the social welfare and 75% with it. And without the social welfare, flood control, gas regulation, climate regulation of the Zoigê Wetland Nature Reserve accounted for 26%, 11% and 8% of the total value, while the proportion that substance production and recreation values were of the total value were very small. Meanwhile, with the social weight,flood control, gas regulation, climate regulation, recreation of the Zoigê Wetland Nature Reserve accounted for 10%,13%, 1% and 1% of the total value, then the weight of substance production value was also the smallest.  相似文献   

4.
The operation of large-scale reservoirs have modified water and sediment transport processes, resulting in adjustments to the river topography and water levels. The polynomial fitting method was applied to analyze the variation characteristics of water levels under different water discharge values in the Jingjiang reach of the Yangtze River from 1991–2016. The segregation variable method was used to estimate the contributions of the varied riverbed evaluation, the downstream-controlled water level, and the comprehensive roughness on the altered water level at an identical flow. We find that low water levels in the Jingjiang reach of the Yangtze River from 1991–2016 are characterized by a significant downward trend, which has intensified since 2009. Riverbed scouring has been the dominate factor causing the reduced low water level while increased roughness alleviated this reduction. From 1991–2016, there was first a decrease followed by an increase in the high water level. The variation characteristic in terms of the "high flood discharge at a high water level" before 2003 transformed into a "middle flood discharge at a high water level" since 2009. The increased comprehensive roughness was the main reason for the increased high water level, where river scouring alleviated this rise. For navigation conditions and flood control, intensified riverbed scouring of the sandy reaches downstream from dams enhanced the effects that the downstream water level has on the upstream water level. This has led to an insufficient water depth in the reaches below the dams, which should receive immediate attention. The alteredvariation characteristics of the high water level have also increased the flood pressure in the middle reaches of the Yangtze River.  相似文献   

5.
Flooding 1990s along the Yangtze River, has it concern of global warming?   总被引：4，自引：0，他引：4  
1 IntroductionFloods occurring along the Yangtze River (Changjiang River) valley make up about 35.8 % of the floods over China[1]. Most noteworthily, a series of severe floods happened along the middle to lower Yangtze River and caused great damages during the past decade. The flood of 1991 afflicted 0.98 million hectares of farmland and resulted in 1,200 loss of life. Severe flood occurred again over this region in 1996. An extremely destructive flood emerged during the summer of 1998, wh…  相似文献   

6.
In this study,the carbon emissions(CEs)from cultivated land(CL)were included as an undesirable output in the utilization efficiency of such land.A slack-based model was used to calculate the CL use efficiency(CLUE)for 11 provinces and cities in the Yangtze River Economic Belt(YREB)from 2007 to 2016,and then a kernel density estimation map was drawn to analyze the spatiotemporal variations of CLUE.The Tobit model was also employed to analyze the factors affecting the CLUE.The results show the following.1)In the YREB,the CEs from CL showed a rising and then a slowly decreasing trend.In this paper,we calculate CEs by carbon emission factors and major carbon sources,and the CEs from CL in the YREB totaled 25.2354 million tons in 2007.By 2014,the value had increased gradually to 28.4400 million tons,and by 2016 it had declined to 27.8922 million tons,suggesting that the carbon-emission reduction measures of the government had an impact.2)The CLUE of various provinces and cities in the YREB showed an upward trend in the time dimension,while for the spatial dimension,the kernel density was high in the east and low in the west,and the areas with high kernel density were mainly located in the Yangtze River Delta.3)The per capita gross domestic product,the primary industrial output,and the number of agricultural technicians per 10,000 people had positive effects on the CLUE.The CL area per capita and the electrical power per hectare for agricultural machinery had significant negative impacts on CLUE.In addition,every 1%increase in the number of agricultural technicians increased the CLUE by 0.057%.  相似文献   

7.
The water of Bosten Lake was released to lower reaches of the Tarim River for 5 times from 2000 to 2002. The changes of total dissolved solid (TDS) and the major ions (SO4^2-, Cl^-, Na^-,Ca^2 , Mg^2- and HCO3^- ) were analyzed during this period. It was found out that TDS and the concentrations of the major ions initially and quickly increased and then decreased, but finally increased again. These changes were different at different distances from the river, which indicated that the groundwater changes relied on the distance from the river. In addition, the salt in groundwater was only diluted but not removed by the water. It was suggested that ecological measures should be sought to really promote the quality of the groundwater at the lower reaches of the Tarim River.  相似文献   

8.
In this study, data measured from 1955–2016 were analysed to study the relationship between the water level and river channel geometry adjustment in the downstream of the Three Gorges Dam(TGD) after the impoundment of the dam. The results highlight the following facts:(1) for the same flow, the low water level decreased, flood water level changed little, lowest water level increased, and highest water level decreased at the hydrological stations in the downstream of the dam;(2) the distribution of erosion and deposition along the river channel changed from "erosion at channels and deposition at bankfulls" to "erosion at both channels and bankfulls;" the ratio of low-water channel erosion to bankfull channel erosion was 95.5% from October 2002 to October 2015, with variations between different impoundment stages;(3) the low water level decrease slowed down during the channel erosion in the Upper Jingjiang reach and reaches upstream but sped up in the Lower Jingjiang reach and reaches downstream; measures should be taken to prevent the decrease in the channel water level;(4) erosion was the basis for channel dimension upscaling in the middle reaches of the Yangtze River; the low water level decrease was smaller than the thalweg decline; both channel water depth and width increased under the combined effects of channel and waterway regulations; and(5) the geometry of the channels above bankfulls did not significantly change; however, the comprehensive channel resistance increased under the combined effects of riverbed coarsening, beach vegetation, and human activities; as a result, the flood water level increased markedly and moderate flood to high water level phenomena occurred, which should be considered. The Three Gorges Reservoir effectively enhances the flood defense capacity of the middle and lower reaches of the Yangtze River; however, the superposition effect of tributary floods cannot be ruled out.  相似文献   

9.
Saltwater intrusion in the estuary area threatens the use of freshwater resources.If river discharge increases to a critical value,then saltwater intrusion frequency and salinity level decreases.In this study,long-term river discharge and tidal range data in the Yangtze River Estuary(YRE)and salinity data obtained in the upper South Branch of the YRE were used to analyze the characteristics of different variables and the basic law of their interactions.Two methods,namely,the material analysis method and empirical models,were applied to determine the critical river discharge for saltwater intrusion control.Results are as follows:(1)the salinity might exceed the drinking water standard of China when the river discharge was less than 30,000 m^3/s.Approximately 69%of salinity excessive days occurred when the river discharge was less than 15,000 m^3/s;(2)the tidal range in the YRE roughly varied in sinusoidal pattern with a 15-day cycle length.Exponential relationship existed between daily salinity(chlorinity)and daily mean tidal range.Combining these two features with the cumulative frequency statistics of tidal ranges,it was showed that notable saltwater intrusion occurred when the tidal range was more than 2.7 m at Qinglonggang station.Moreover,the critical discharge was found to be slightly higher than 11,000 m^3/s;(3)various of empirical models for salinity prediction could be chosen to calculate the critical discharge.The values obtained by different models were in the range of 11,000–12,000 m^3/s;(4)the proposed critical discharge to reduce notable saltwater intrusion was 11,500 m^3/s.After the Three Gorges Reservoir operation,the minimum river discharge into the YRE in 2008–2017 was below the critical discharge,thereby suggesting an increase in the minimum river discharge by reservoir regulation in drought periods.  相似文献   

10.
Waterfront resources are important and special kind of natural resources in the marginal area between land and water.The Yangtze River,the longest river in China,is not only rich in waterfront resources,but also has favorable development conditions with great potentiality.Aided by large-scale underwater topographic map,the major factors of the waterfront resources in the middle and lower reaches of the Yangtze River,such as the stability,the water depth and the natural conditions for port construction,are assessed in this paper rspectively on the basis of the overall investigations.The results show that:(1)the waterfront resources are abundant in the middle and lower reaches of the Yangtze River,but lack of perfectly combined high grade waterfront;(2)there exists and obvious regional difference in the natural quality of the waterfront along the Yangtze;(3)the fore-bank water depth and waterfront stability are the main natural factors related to the waterfront auality in the middle and lower reaches of the Yangtze River;(4)the waterfronts along the Yangtze are mainly used for port,warehouse and industrial pruposes; and (5)the waterfronts near important cities are highly used,especially the high-quality waterfronts.In addition,some suggestions for the development and utilization of the waterfront resources are presented in this paper.  相似文献   

11.
构建长江干流地区沿江城市带   总被引：1，自引：1，他引：0  
建设沿江城市带是为了顺应现代城市的发展潮流,加速沿江地区区域经济一体化的进程。建立沿江区域协调发展体系、走大中小城市协调发展的城市化道路、巩固长江发展轴的核心地位、统筹沿江重大基础设施的建设是城市带发展的总体构想。由于沿江各地区发展条件迥异,城市带的建设采取了分区发展的模式,在沿江地区总的发展框架内,设想在城市带内构建7个城市群、城市组团等,根据各集团的特征,制定不同的发展战略。  相似文献   

12.
长江中下游河道岸线的整治与开发利用   总被引：2，自引：2，他引：2  
通过分析长江中下游河道的各段的整治措施，提出长江中下游河道整治的关键是：（1）控制河势，治理河岸崩塌，增强河床与河岸的稳定性；（2）充分重视三峡工程建成后对河道变化产生的影响；（3）科学合理地控制好长江采砂。并分析了长江岸线开发利用现状及存在问题，提出了岸线利用的原则。在长江中下游河道岸线利用过程中，还存在：河势不稳定，布局不合理，深水浅用浪费岸线资源和水污染严重等问题，提出遵照河道演变规律开发岸线，保护河岸工程的安全，根据河岸水质污污染与河床特点合理布置引水口和排污口，提高引水质量。  相似文献   

13.
Waterfront resources are important and special kind of natural resources in the marginal area between land and water. The Yangtze River, the longest river in China, is not only rich in waterfront resources, but also has favorable development conditions with great potentiality. Aided by large-scale underwater topographic map, the major factors of the waterfront resources in the middle and lower reaches of the Yangtze River, such as the stability, the water depth and the natural conditions for port construction, are assessed in this paper respectively on the basis of the overall investigations. The results show that: (1) the waterfront resources are abundant in the middle and lower reaches of the Yangtze River, but lack of perfectly combined high grade waterfront; (2) there exists an obvious regional difference in the natural quality of the waterfront along the Yangtze; (3) the fore-bank water depth and waterfront stability are the main natural factors related to the waterfront quality in the middle and lower reaches of the Yangtze River; (4) the waterfronts along the Yangtze are mainly used for port, warehouse and industrial purposes; and (5) the waterfronts near important cities are highly used, especially the high-quality waterfronts. In addition, some suggestions for the development and utilization of the waterfront resources are presented in this paper.  相似文献   

14.
长江、黄河流域生态系统服务变化及权衡协同关系研究   总被引：6，自引：1，他引：5  
长江、黄河流域是中国重要的生态屏障,近几十年来强烈的人类活动改变了长江、黄河流域的自然景观,使生态系统功能遭到破坏,了解流域内生态系统服务的变化、相互作用和驱动因素是流域生态系统管理和调控的重要基础。本文利用土地利用、土壤类型和气象等数据,对2000—2016年长江、黄河流域的NPP、土壤保持和产水服务进行时空变化分析;采用相关分析法和约束线研究生态系统服务之间的权衡协同关系和约束效应。结果表明：① 2000—2016年,长江、黄河流域的NPP分别以3.21 gC/m2和3.92 gC/m2的速率递增,产水量和土壤保持量在长江流域分别以1.25 mm/a的速率递增和55 t/hm2的速率递减,而在黄河流域,产水量和土壤保持量分别以0.04 mm/a的速率递减和3.31 t/hm2的速率递增。② 长江、黄河流域的NPP、土壤保持和产水服务之间互为协同关系。长江流域的NPP和产水服务与土壤保持服务之间为驼峰型约束,NPP与产水量之间为凸波型约束。③ 黄河流域的NPP与土壤保持间的约束线形态为凸波型,NPP与产水量之间为驼峰型约束,而产水量与土壤保持之间为指数型。定量化研究不同流域的生态系统服务并探究其影响因素,对于了解和优化不同地区的生态系统服务有重要意义。  相似文献   

15.
长江沿岸28个城市的低碳化发展评价   总被引：1，自引：0，他引：1  
长江沿岸上、中、下游28个地级以上城市可视为我国东、中、西部城市的缩影,因此,沿江城市的低碳化发展水平客观上反映着中国低碳城市整体发育程度与区域差异。在分析、理解低碳城市内涵的基础上,构建低碳城市评价指标体系,提出低碳指数概念,并从时空路径对长江沿岸28个城市的低碳指数进行聚类分析与评价。认为我国低碳城市建设应该以不影响社会经济快速发展为根本前提,低碳城市发展应该以平均相对量指标作为评价标准;不同城市可根据构成低碳指数的3个分项指标的具体情况,制定相对应的低碳城市发展战略,提高城市综合低碳指数。  相似文献   

16.
实施流域生态管理的长江中下游湿地保护探讨   总被引：4，自引：1，他引：4  
长江中下游地区湿地分布广泛且类型多样,是我国淡水湖泊分布最集中和最具有代表性的地区。为了从根本上解决长江中下游湿地利用面临的问题,实现湿地资源的可持续利用,保护湿地环境,解决区内上、下游用水的供需矛盾,实现水资源的优化配置,调动区域湿地保护的积极性和主动性,有必要遵循湿地流域分布规律,应用流域生态学最新理论与实践成果,进行流域生态管理。一方面,要从流域角度处理好几大江湖关系、蓄泄关系、湖垸关系和山湖(河)关系等;另一方面,在流域内建立统一协调机制,对流域湿地进行保护与合理利用、合理布局和统一规划;同时在保护的前提下,科学合理地利用长江中下游湿地资源,开拓新的生产力。  相似文献   

17.
长江流域国土空间开发适宜性综合评价   总被引：22，自引：0，他引：22  
唐常春  孙威 《地理学报》2012,67(12):1587-1598
国土空间开发适宜性评价是国土开发格局优化与区域协调发展的科学基础,开展长江 流域国土空间综合评价,可以加强和深化对流域国土空间合理开发的科学认知,指导流域治 理与可持续发展实践。根据“3步骤4原则”首次界定长江流域覆盖的县级行政区域范围,从 长江流域实际出发,采用Delphi与AHP方法,构建国土空间开发适宜性综合评价指标体系, 建立以724个县级行政区为基本单元的长江流域综合数据库。在此基础上,结合专业知识与 GIS 空间聚类方法进行单因子分级评价,运用动态加权求和法建立测度模型开展综合评价,构 建耦合差系数模型进行人口-经济空间耦合度分析。研究结果表明：全流域开发约束总体水 平较高,高值区 (V~VIII级) 主要分布在上中游地区。开发强度和开发潜力的空间集中度高, 区域发展差异呈继续扩大态势。综合评价分级高值区土地面积比重为22.95%,表明适宜开发 区域仅占少部分流域国土面积;人口-GDP耦合差系数 (D值) 为8.70,流域人口与经济空间 耦合度较低;上中下游开发适宜性存在显著差异,适宜性高值区主要包括长江三角洲、合肥 与皖江沿线地区、武汉城市圈、荆州-宜昌长江沿线地区、襄阳-南阳地区、长株潭城市 群、南昌-九江-新余地区、成渝城市群、贵阳-安顺地区、昆明市及大部分地级城市。  相似文献   

18.
An acoustic Doppler current profiler is used to characterize the river velocity against the morphology of the Yangtze River from Chonqing to the sea. High flow velocities occur in the Three Gorges section and lower velocities in the middle and lower reaches of the river. This is largely due to the change in river pattern from a high gradient deeply-cut valley to a flat fluvial plain. Flow velocities fluctuate in the middle Yangtze due to the presence of meander bends of different length. There are numerous smaller velocity fluctuations in the lower Yangtze channel that reflect multichannel pattern with numerous sand bars and a river morphology affected by bedrock outcrops. Water depths of 40–100 m occur in the Three Gorges valley but decrease to 15–40 m in the middle and lower Yangtze. At the Gezhou Reservoir, 30 km downstream of the Three Gorges damsite velocity drops to low (< 1.0 m s− 1) 20 km reach. A second low velocity (< 0.5 m s− 1) zone, about 20 km in length, is located in the lower Yangtze near the coast probably due to the tidal influence. The results from this research will serve as a datum for evaluating changes to the river once the Three Gorges dam is completed in 2009.  相似文献   

19.
长江中下游阻隔性河段作用机理   总被引：1，自引：0，他引：1  
阻隔性河段能够阻隔上游河势调整向下游的传递,对稳定河势起到关键性作用。本文以长江中下游34个单一河段为研究对象,在系统总结长江中下游河道演变规律的基础上,归纳出阻隔性河段控制要素包括：单一微弯的河道平面形态、河段中上部无挑流节点;河相系数小于4;河道纵比降大于1.2?;凹岸黏粒含量高于9.5%;床沙中值粒径大于0.158 mm等。从Navier-Stokes方程出发,推导出河湾水流动力轴线弯曲半径的表达式,进而分析了各控制要素对水流动力轴线摆动及阻隔性河段形成的作用。阻隔性河段的判别条件为：不同流量级下水流动力轴线摆动力与河道边界条件约束力的比值始终小于1;阻隔性河段作用机理在于：即便上游河势发生调整,本河段的河道边界始终能约束主流摆动幅度,归顺上游不同河势条件下的主流平面位置,为下游河道提供了相对稳定的入流条件,从而阻隔上游河势调整向下游传递。  相似文献   

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