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排序方式: 共有173条查询结果,搜索用时 31 毫秒
51.
浦宝康 《交通环保》1999,20(5):30-31
行驶于中国江河湖海的成千上万艘小于400 总吨的船舶,是造成水域环境油污染的主要原因之一。国际防污公约对这类船舶的防油污措施并无详细规定。文中介绍一种相应的举措,可供各地主管部门、船东、船舶修造厂、船员等参考。  相似文献   
52.
Brouwer R  Nhassengo J 《Disasters》2006,30(2):234-255
Massive floods hit Mozambique in 2000.1 Many of the affected regions benefited from external aid. This paper investigates how the floods impacted on two communities in the interior of the Limpopo Valley, which did not receive significant assistance during the event and in the immediate aftermath. Drawing on the livelihood approach, it focuses on the role of two types of local resources: knowledge and social capital. The paper shows that the scale of the 2000 floods surpassed the response capacity of these resources and looks at how wealth and gender influenced access by households to the local support mechanisms that enhance survival and recovery. It appears that the floods mainly affected wealthier households, as these more frequently lost houses and cattle. The paper points to the importance of ploughs and cattle for local support mechanisms, which, in turn, most likely reduced the capacities of communities to recover from the disaster.  相似文献   
53.
Abstract: While transboundary flood events have become more frequent on a global scale the past two decades, they appear to be overlooked in the international river basin (IRB) cooperation and management arena. The present study therefore combined geopolitical measures with biophysical and socioeconomic variables in an attempt to identify the IRBs with adequate institutional capacity for management of transboundary floods. It also classified basins that would possibly benefit from enlarging the institutional capacity related to transboundary floods. Of the 279 known IRBs, only 78 were represented by a transboundary rivers institution. A mere eight of the 153 identified institutions had transboundary flooding listed as an issue in their mandate. Overall, 43 basins, where transboundary floods were frequent during the period 1985‐2005, had no institutional capacity for IRBs. The average death and displacement tolls were found to be lower in the 37 basins with institutional capacity, even though these basins experienced twice as much transboundary floods with significant higher magnitudes than those in basins without institutional capacity. Overall, the results suggested that institutional capacity plays a role in the reduction of flood‐related casualties and affected individuals. River basins such as the Juba‐Shibeli, Han, Kura‐Araks, Ma, Maritsa, Po, Coco/Segovia, Grijalva, Artibonite, Changuinola, Coatan Achute, and Orinoco experienced more than one transboundary river flood, but have not yet set up any institutions for such events, or signed any appropriate treaties focused on floods. These basins were therefore recommended to consider focusing attention on this apparent lack of institutional capacity when it comes to managing transboundary flood events.  相似文献   
54.
城市化过程中黑碳的土壤记录及其环境指示意义   总被引:6,自引:0,他引:6  
以南京市为对象,通过3组共计10个土壤剖面的采样,用湿化学氧化法分析了土壤有机碳(organic carbon,OC)和黑碳(black carbon,BC)的含量.研究发现,南京城市土壤剖面中黑碳含量的变幅为0.22~32.19 g·kg-1,平均值为4.35 g·kg-1.第1组城市土壤剖面中黑碳含量的平均值为0.91 g·kg-1,第2组为8.62 g·kg-1,第3组为3.72 g·kg-1.城市土壤剖面中BC/OC值的变幅为0.03~1.59,平均值为0.29,其中BC/OC平均值的大小顺序是:受古代工业活动影响的第2组最大,受现代工业和交通人为活动影响的第3组次之,受古代居民生活影响的第1组最低.研究认为,在城市化过程中,由于工业和交通等人类活动引起的生物物质和矿物燃料(煤、石油等)燃烧产生的BC在土壤中都有不同程度的沉积和记录.BC含量和BC/OC值的大小可能在一定程度上反映了不同人为影响过程和城市土壤的污染程度.城市区域BC的主要来源是矿物燃料燃烧,其中表层(现代层)主要来自交通车辆(尤其是柴油为动力的机车)排放的颗粒物质,而在古代(文化层)可能与燃烧用煤历史有关.  相似文献   
55.
ABSTRACT: Ash trees (Fraxinus americana L. and F. Pennsylvanica Marsh.) collected from the flood plain of the Potomac River near Washington, D.C., were studied for evidence of associations between known periods of above-average summer flows and changes in wood-growth anatomy. Concentric bands of latewood fibers with atypically large lumens and thin walls commonly developed in trees growing near the low-water channel. Discharge records indicate that roots of most trees with these “white rings” were flooded temporarily during the latewood-growth interval. Trees apparently were not damaged and a concomitant reduction of internal water stresses seems to have accelerated the rate of radial growth. The intra-ring position of anomalous fibers generally corresponded to the time of increased discharge within the estimated interval of latewood growth. Anomalous fibers occasionally formed in unflooded trees, but their position also coincided with episodes of increased discharge. The results of these studies may have applications for streamflow-reconstruction techniques where hydrologic data are incomplete or lacking.  相似文献   
56.
The extinction of many species can only be inferred from the record of sightings of individuals. Solow et al. (2012, Uncertain sightings and the extinction of the Ivory‐billed Woodpecker. Conservation Biology 26: 180–184) describe a Bayesian approach to such inference and apply it to a sighting record of the Ivory‐billed Woodpecker (Campephilus principalis). A feature of this sighting record is that all uncertain sightings occurred after the most recent certain sighting. However, this appears to be an artifact. We extended this earlier work in 2 ways. First, we allowed for overlap in time between certain and uncertain sightings. Second, we considered 2 plausible statistical models of a sighting record. In one of these models, certain and uncertain sightings that are valid arise from the same process whereas in the other they arise from independent processes. We applied both models to the case of the Ivory‐billed Woodpecker. The result from the first model did not favor extinction, whereas the result for the second model did. This underscores the importance, in applying tests for extinction, of understanding what could be called the natural history of the sighting record. Sobre Avistamientos Inciertos e Inferencia de la Extinción  相似文献   
57.
受息烽河输入的影响,乌江渡水库的磷污染问题一直备受关注,但水库上游水体磷的释放以及河流筑坝对水库磷污染的影响却没有引起太多的重视。本文通过对表层沉积物和沉积物柱芯中磷及其形态的分析,研究乌江渡沉积物磷的污染现状和历史变化趋势及其对河流筑坝的响应。结果表明:1)乌江渡水库沉积物磷污染现已非常严重,远高于国内其他湖库;2)乌江渡沉积物磷含量从上游至下游有递增的趋势,且主要由NaOH-P的增加所致;3)乌江渡沉积物磷的空间变化可能源于不同粒径颗粒物或藻类的沿程沉降,也可能源于水体中Fe2+被氧化后引起磷的沿程沉降,但真实原因还需要进一步的证实。这说明上游水库滞留在沉积物中的磷部分可能重新释放出来,导致乌江渡水库中上游沉积物磷的污染也相当严重。  相似文献   
58.
基于历史文献法收集整理了《四川两千年洪水史料汇编》中嘉陵江清代洪水碑刻的碑文记录,并利用Gibbs-Mirtin多样化指数法分析洪水碑刻记录的空间分布特征。结果发现:清朝时期,嘉陵江流域共有洪水碑刻记录55通,月份明确可辨的有36通。空间上整体分布不均,下游多于中上游,其中嘉陵江干流28通(20通有明确月份;Gibbs-Mirtin多样化指数为0.46,上游仅有零星分布,相对集中于中下游),渠江16通(10通有明确月份;Gibbs-Mirtin多样化指数为0.71,各河段均有分布),涪江11通(6通有明确月份;Gibbs-Mirtin多样化指数为0,仅集中于下游的重庆市)。洪水碑刻记录在年内主要分布于6、7、8、9四个月,洪水碑刻清晰记录了清代1679年(2通)、1840年(3通)、1870年(17通)、1903年(2通)4次特大洪水,洪水碑刻记录的嘉陵江流域清代洪水的发生频率为7 a一洪。清代嘉陵江洪水碑刻记录反映了流域夏秋季洪水较多,这与嘉陵江流域的亚热带湿润季风气候、多洪齐发的扇状水系、低山丘陵-谷坝地形、松散的土壤质地以及"湖广填川"时期毁林垦荒导致的水土流失与河道淤积有关。  相似文献   
59.
The Manawatu floods of 2004 have had significant, long-lasting social consequences. This paper draws on findings from a series of detailed surveys of 39 farm households directly affected by the floods and 17 individuals directly involved in managing the flood recovery programme. The nature of the impact on rural families highlights how the 'hollowing out' of rural New Zealand has changed the capacity of rural communities to respond to natural hazards and increased their sense of isolation. In addition, the floods exposed the vulnerability of rural communities. This is shown to have implications for policies designed to build resilience and improve responses to adverse events, including the need to support local, community initiatives on self-reliance and mutual support. Approaches to manage better long-term flood risks should be designed within a context of ongoing rural decline that has compromised the health of both individuals and communities.  相似文献   
60.
湖北省的洪涝灾害受全球尺度和流域尺度的多种因素的影响。全球尺度因素是指全球性的气候异常,流域尺度因素是指不利的自然条件和人类对自然环境与自然资源的不合理开发利用等方面。现阶段所采用的治水对策,即生态措施和工程措施,存在明显的局限性,不能彻底根治水患。通过系统分析湖北省水患原因和治水对策,提出以洪涝灾害承灾区的受因人口和受因财产的总数定量地表示洪涝灾害灾情的指标,该指标与灾情的对应关系明确且简明易得,为治水对策提供了更合理的依据。在此基础上,论述了“提高洪涝灾害承灾区的城市化水平、鼓励抗洪新技术和新机制的开发利用以及加强溃堤后的应对策略研究”等治水对策的必要性、合理性和可行性。  相似文献   
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