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101.
102.
Copula-based identification of the non-stationarity of the relation between runoff and sediment load
It is important to identify the non-stationarity in the relation between runoff and sediment load under the backdrop of the changing environment. This relation helps to further understand the mechanisms of runoff and sediment yield. A copula-based method was used to detect possible change points in the relation between runoff and sediment load in the Wei River Basin (WRB), China, where soil erosion is a very severe issue. The modified Mann-Kendall trend test method was applied to obtain the trends of runoff and sediment load spanning 1960–2010 at monthly and annual timescales. Finally, the causes of the identified non-stationarity of the relation between runoff and sediment load were roughly analyzed from the perspective of climate change and human activities. Results indicated that:(1) the runoff and sediment load in the Jinghe and Wei rivers were generally characterized by noticeably decreasing trends at both monthly and annual timescales;(2) both the Jinghe and Wei rivers had a common change point (2002), implying that the stationarity of the relation between runoff and sediment load in the Jinghe and Wei River was invalid; (3) human activities including increasing water consumption and growing application of soil conservation practices are dominant factors resulting in non-stationarity in the rela-tion between runoff and sediment load in the WRB. This study provides a new idea for identifying the non-stationarity of multivariate relation in the hydro-meteorological field under the background of the changing environment. 相似文献
103.
流域资源具有公共池塘资源的属性,私人在流域资源的开发过程中可能会产生外部性问题,因而要求政府对流域开发、利用进行管理.但由于实际上政府并不是只有单一目标的统一的组织,在分权体制下,不同区域、部门的政府单元掌握着实际权力.由于权力也存在外部性,各管理区域、部门之间存在利益冲突,导致政府的管理失效.解决政府权力外部性的办法一是要转变政府职能,改变政府的激励机制,二是严格界定各政府单元的权力界限,对流域进行统_管理. 相似文献
104.
随着水资源短缺程度的加剧,可交易水权制度逐渐成为当今世界水资源管理制度发展的新方向.水资源初始产权是水资源管理的基础和前提.在干旱区内陆河流域,产权初始配置要在生态环境可持续的前提下,坚持公平、效益相结合的分配目标和配置原则.通过建立初始水权配置指标体系,对黑河流域进行实地问卷调查,在此基础上对用户调查结果进行专家判断修正,应用层次分析法研究了各分配指标的权重分布.以黑河流域张掖地区为例的界定结果表明,除上游的肃南县和山丹县外,其余各县市的实际用水量都超过了各自界定的初始水权,这种差别为水资源产权交易管理提供了现实依据,为开展流域上游的生态保护补偿提供了理论基础. 相似文献
105.
《Marine Policy》2017
This paper identifies three management initiatives in New Zealand's Individual Transferable Quota system that facilitated consolidation of the processing sector and limited market access for fishers, even those with quota rights. They are: (1) the placement of responsibility onto a Māori trust in 1992 and tribes (iwi) in 2004 to manage a limited amount of quota to benefit all Māori, fishers and non-fishers, which increased the use of quota as an investment asset; (2) the creation of Annual Catch Entitlement (ACE) as a fish access right separate from the quota ownership right, which made it possible to overcome consolidation limits by leasing ACE; (3) the 1997 Licensed Fish Receiver Act that made it illegal for fishers to sell fish off the boat without food safety certification. This account of the fishery policy environment in New Zealand explains why, despite owning significant portions of New Zealand's fishing quota, few Māori are fishing, processing, or selling fish caught by Māori quota. 相似文献
106.
《Marine Policy》2017
Assessing the vulnerability of species to [anthropogenic threats is an essential step when developing management strategies for wild populations. With industrial development forecasted to increase in Spencer Gulf, South Australia, it is crucial to assess the ongoing effects of anthropogenic threats to resident and migratory species. Expert elicitation was used to assess 27 threats against 38 threatened, protected, and iconic marine-associated species. Species and threat interactions were assessed individually, and as taxonomic or functional groups. Climate change had the greatest overall exposure (c.f. risk) across species, followed by disturbance, pollution, disease/invasive species, and fishing/aquaculture threats. The largest overall sensitivities (c.f. consequences) were pollution and disease/invasive species, followed by climate change, disturbance and fishing/aquaculture threats. Vulnerability scores (exposure x sensitivity) showed the climate change group posing the greatest overall threat in Spencer Gulf, with individual climatic threats ranking as three of the top four biggest threats to most animal groups. Noise, shipping, and net fishing were considered the greatest region-specific individual threats to marine mammals; as were trawl fishing, line fishing, and coastal activities to fish/cuttlefish; trawl fishing, line fishing, and net fishing to elasmobranchs; and oil spill, disease, and coastal activities to sea/shorebirds. Eighteen of the 20 highest vulnerability scores involved the short-beaked common dolphin, Indo-Pacific bottlenose dolphin, and Australian sea lion, highlighting the particular susceptibility of these species to specific threats. These findings provide a synthesis of key threats and vulnerable species, and give management a basis to direct future monitoring and threat mitigation efforts in the region. 相似文献
107.
社会公正是当前地理学的一个热点也是传统研究课题。住房问题往往是社会公正研究和实践的重点案例。中国住房制度改革之后,中国住房拥有率及人均住房面积均大幅度提高。然而在住房分配的过程中,不平等和不公正现象时有发生。如何区别平均和公正,如何看待中国住房改革中的社会公平与不公共存的现象,是了解中国新城市现象的一个重要途径。本文从近期西方政治学和地理学关于住房权(housing rights)、社会公正以及城市权利等文献的讨论出发,通过在广州的实证研究,运用结构方程模型和Pratt指数对涉及住房权主要方面的住房分异的发生途径及其公正性进行综合分析。实证研究说明在住房分配领域,存在着制度因素延续下来所导致的分异。一些制度因素已经转化为市场因素,直接或间接影响个人居住条件和住房所有权的获得,并通过后者进一步影响住房分异。与此同时,纯粹市场因素的影响则相对薄弱。上述结论有助于了解当前中国城市住房权的核心问题,认识社会公正的发展前景,以及探寻减少社会不公正的制度利器。 相似文献
108.
The distribution and bioaccumulation features of PCBs, DDTs, and HCHs were investigated in the sediments and Manila clams collected from along the Mid-Western coast of Korea. The measured concentrations of ΣPCBs, ΣDDTs and ΣHCHs were 1.08–3.5, 0.12–0.35 and 0.090–0.30 ng g−1 dw in sediment, and 33–390, 7.4–46 and 6.3–27 ng g−1 lipid in Manila clam, respectively. Their levels were found to be relatively lower than those of other contaminated areas and the consumption of Manila clam from these areas seems to be safe for human health according to calculated lifetime cancer risk and hazard indices. The ΣPCBs and ΣDDTs concentrations in sediments showed a significant relationship to those in clams. The significant correlation was observed between BSAF in clams and Kow for each PCB congeners and DDT metabolites. These findings support that the PCBs and DDTs levels, which are highly hydrophobic chemicals, in clam reflect the sediment pollution through bioaccumulation. 相似文献
109.
Chang-li LIU Chao SONG Hong-bing HOU Xiu-yan WANG Yun ZHANG Jun-kun WANG Jian-mei JIANG Li-xin PEI Bo SONG 《地下水科学与工程》2014,2(1):29-38
The chemical weathering can consume atmosphere/soil CO2. Human activities such as pollution, fertilization and acid precipitation have exerted a large impact on CO2 intake by carbonate weathering. Thus, based on the analysis on chemical component change of the karst groundwater in the karst ridge watershed of Conglin Village, Fuling District of Chongqing City, the influence of human activities such as fertilization, sewage discharges from mustard tuber processing, breeding industry and acid rain precipitation on carbonate weathering and CO2 intake in 1980, 2003 and 2006 was studied. The results showed that CO2 intake by carbonate rock declined with year. Because H+ derived from acid sewage discharge, fertilization and acid precipitation reacted with carbonate rock when mustard tuber production and swine breeding were developed fleetly after 2000 as well as the burning amount of high-sulfur coal augmented persistently, which led to the increase of (Ca2++Mg2+)/HCO3-. The difference on charge between Ca2++Mg2+ and HCO3- was balanced by NO3-+SO42-. The control on pollution and acid rain, especially the pre-neutralization of acid waste water, would rejuvenate the atmospheric CO2 intake strength of carbonate weathering besides the protection of water and soil environment 相似文献
110.
Variation in DOC and trace metal concentration along the heavily urbanized basin in Kathmandu Valley,Nepal 总被引:1,自引:0,他引:1
Water samples were analyzed for DOC and trace metals from Bagmati River within Kathmandu valley, Nepal, to understand the
variation trends of DOC and trace metals and their relationship along the drainage network. The variability in organic matter
and wastewater input within the Bagmati drainage basin appeared to control DOC and most of the trace metal concentration.
The large input of organic matter and wastewater creates anoxic condition by consuming dissolved oxygen and releasing higher
concentrations of DOC, trace elements such as nickel, arsenic, barium, cadmium, and copper with downstream distance. Concentrations
of DOC and trace metals like barium and zinc showed strong relationships with human population density and suggest that human
activities have strong control on these parameters along the drainage network. The DOC and most of the trace metal concentration
increased with downstream distance and appeared to be directly associated with human activities. The variation trends of most
of the trace metals appeared to be the same; however, concentration varied widely. Inputs of organic matter and wastewater
due to human activities appeared directly to be associated for the variation of DOC and trace metals along the Bagmati drainage
network within Kathmandu valley. 相似文献