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41.
作为国际河流长期合作开发的重要保障,国际河流流域组织这一联合制度安排备受关注,但参差不齐的绩效表现致使其可行性与有效性引发学者质疑。我国拥有众多国际河流,与之相关的合作开发是中国周边外交的重要抓手,但针对上述问题的研究未能得到国内学者的足够重视。在此背景下,文章首先回顾、梳理了国际河流流域组织的定义与类型,然后重点研判其制度设计特征和有效性,并指明已有研究所面临的方法困境,最后为解开“流域组织如何促进国际河流有效合作”这一难题提出以下研究建议:1)整合国际河流流域组织有效性评价指标并进行全球范围的评价;2)探明国际河流流域组织制度类型所适用的范围与条件;3)厘清不同国际河流流域组织制度设计特征与治理有效性的关系;4)基于过程视角探求国际河流流域组织有效性达成路径;5)采用超越定性与定量研究的新方法;6)立足地缘文明激发国际河流流域组织成员国的文化认同。  相似文献   
42.
Urbanization is a complex process that covers a wide range of topics, of which population, industry and land urbanization are three important aspects. Jilin Province is an important agricultural province in China. The contradiction between population, industry and land urbanization is especially prominent here, and its coupling development is of great practical significance. In this paper, the coupling degree of population-industry-land urbanization in Jilin Province in 1990, 2000 and 2010 is measured by coupling mode. The spatial pattern of the coupling degree is analyzed by trend surface analysis and global and local spatial autocorrelation. The influence factors and their spatial differentiation are discussed using multiple linear regression (MLR) model and geographic weighted regression (GWR) model. The results show that: 1) the coupling degree of population-industry-land urbanization in Jilin Province is at a low level. Judging from the change of time scale, the urbanization of most research units is becoming more and more coordinated. From the comparison of spatial scales, there is significant spatial difference in the research units of different administrative levels. 2) Judging from the global change trend, the coupling degree of population-industry-land urbanization in the central region is higher than that in western and eastern regions. The coordination of urbanization in the central region is relatively good, and the distribution of the cold and hot spots is basically the same as that overall. 3) The spatial pattern of the coupling degree is related to the cold and hot spot distribution of the influence coefficient of urban population density and per capita urban construction land. The variation of the coupling degree spatial pattern is synchronous with the spatial change of the urban population density influence coefficient. 4) The degree of agglomeration of the urban population is the main factor promoting the coupling pattern of population-industry-land urbanization in Jilin Province, and the extent of its influence is gradually increasing. In addition, the level of city administrative, the efficiency of urban expansion and the capacity of market consumption also have an important influence on the coupling pattern.  相似文献   
43.
赵丽元  韦佳伶 《地理科学进展》2020,39(11):1898-1908
城市内涝灾害频繁,用地开发与空间扩张被普遍认为是其致因之一。对比武汉市遥感数据,1984—2017年,超过30%的自然水体被填占开发,城市建设开发活跃、填湖造陆强度大。论文以武汉市为例,采用二项Logistic模型,定量分析不同降雨强度情景下的内涝影响因素。研究表明,填湖造陆将极大地增加极端降雨情景下城市滨水区域的内涝风险。城市地形地势、排水管网条件、用地类型以及邻域用地结构等因素,也直接影响内涝风险。基于2种不同的用地开发策略,预测城市内涝风险结果显示,城市用地的不当开发将引致严重内涝风险。依据内涝风险的空间分布预测结果,论文提出了相应的改善策略,以为科学地制定防涝减灾规划提供参考。  相似文献   
44.
气候是影响植被类型和分布的关键因素,植被类型和分布格局也能反映气候的地域差异。随着气候变暖,全球气温和降水格局都将发生变化,植被类型和分布格局也将随之改变。而植物对气候变化的响应存在一定的滞后性,因此仅用气候指标研究亚热带北界及其移动具有一定的局限性。以青冈(Cyclobalanopsis glauca (Thunberg) Oersted)为研究对象,应用最大熵模型(Maxent),研究了其对气候变化的响应并探讨了气候变化情景下青冈分布格局变化对中国亚热带北界移动的指示意义。结果表明:影响青冈分布的主导环境因子为年降水量、最冷季降水量、气温年变化范围和最冷月最低气温;随着气候变暖,青冈分布北界将向北移动,其分布质心亦向西北移动,预示着在气候变暖的背景下,到21世纪中叶中国亚热带北界将向北移动约1个纬度。  相似文献   
45.
为研究盘锦海岸线的时空变迁,文章基于面向对象的多尺度分割技术,利用局部方差变化率算法计算水域的最优分割尺度,使用隶属度分类得到水边线,通过潮汐改正提取海岸线,系统分析1990-2018年盘锦沿海4个研究区的海岸线长度、变化距离和变化率以及海岸带向海推进面积的时空变化特征及其驱动因素。研究结果表明:4期影像水边线提取的最优分割尺度分别为118、91、114和104;辽河口、临港工业区、盘锦港区和辽滨主城区海岸带向海推进面积分别为99.96 km2、43.96 km2、26.62 km2和26.91 km2;盘锦海岸线的巨大变化主要是由于资源枯竭型城市向海发展、全面转型和以港强市的政策导向作用。  相似文献   
46.
Prediction of colloid release and transport as affected by reactive species remains a significant challenge for field applications. In this paper, we report experimental and modeling results of ferrihydrite colloid release under the influence of citrate species. Using a 3-plane surface complexation model, equilibrium constants were obtained for the three proposed inner-sphere complexes by fitting a citrate adsorption isotherm on ferrihydrite at pH 4, and a pH adsorption envelop with 0.64 mM citrate. The constants were used in a reactive transport model for simulating reaction fronts of dissolved species during injection of citrate in ferrihydrite-coated quartz columns. Simulation results show that sorption alone may not adequately describe the breakthrough curves. Inclusions of ferrihydrite dissolution and re-adsorption of Fe(III) improve the prediction of dissolved species transport. Additionally, matrix diffusion may be needed for improved prediction. For the release of colloidal iron oxides it was shown that both oxide dissolution and interfacial repulsion controlled the process during complete breakthrough. However, the peak release of colloids, which occurred during the actual breakthrough of dissolved species, was mainly brought about by electric double layer forces. These particles underwent detachment-deposition-detachment cycles along the flow path, and emerged in the effluent with the major reaction front. To quantitatively predict colloid release, a semi-empirical linear correlation was established, linking the calculated electric potential to experimental colloid release rates. The model may be applied to the prediction and scaling of aquifer remediation studies involved in the injection of organic ligands to mobilize particle bound contaminants.  相似文献   
47.
Climate of Yunnan Plateau is mainly controlledby the system of southwest Asian monsoon, and alsoaffected by westerlies and local climate of the Qing-hai-Tibet Plateau. Since the Cenozoic, a large numberof structural lake basins have formed with the uplift ofthe Qinghai-Tibet Plateau[1]. As the information aboutthe climate and environment change was faithfullydocumented in lake sediments, which have the char-acteristics of continuity, high resolution, abundant in-formation, lake sediments p…  相似文献   
48.
Spatial and temporal changes in ecosystem services(ESs) are driven by two types of factors: environmental factors and trade-offs/synergies between services. In the ecological conservation red line(ECRL) area, in which national ecological security and social sustainable development are guaranteed, it is particularly important to clarify the driving mechanism of ESs for the management of ecosystems. In this study, soil conservation, water yield, and carbon sequestration in Beijing’s ECRL area are ...  相似文献   
49.
针对气象信息网络常规运行监控业务需要,结合气象信息共享系统(China Integrated Meteorological Information Service System,简称CIMISS)的运维实际,设计开发了基于CIMISS的气象数据处理时效监视系统,实现了对13类上行气象观测数据处理主要的节点时效、自动站疑误数据处理、数据访问服务性能的实时监控,并可为部分气象观测设备的运维保障提供参考指引。文中从系统结构与数据流程、主要业务功能、技术实现等方面对系统的实现方式等进行了介绍。  相似文献   
50.
以2006-2008年的南四湖4条入湖河流水质监测数据为基础,以溶解氧、高锰酸盐指数、5日生化需氧量和氨氮作为监测项目,采用综合水质标识指数评价法对南四湖入湖河流进行水质评价.结果表明,除泗河监测断面水质为Ⅲ类水体外,其他都属于Ⅳ、Ⅴ类水体,污染较为严重.本研究可为南四湖主要入湖河流的污染治理提供一定的科学依据.  相似文献   
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