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61.
The UK is committed to meeting a series of ‘high-level marine objectives’ which are required to satisfy national obligations and to meet international commitments for the marine environment. There are more than 16 such international high-level policy driven obligations and commitments, together with more than 18 European and more than 12 of national origin. In the UK, there is an assumption that the current and planned monitoring will provide evidence to demonstrate achievement against these high-level objectives.  相似文献   
62.
Advances on Assessment of Bioclimatic Comfort Conditions at Home and Abroad   总被引:2,自引:0,他引:2  
The evaluation of bioclimatic comfort conditions has very important theoretical meaning and practical value, not only beacause it can help travelers choose their favorate holiday destinations, but also because it can provide scientific foundation for the assessment of urban living environment. It has become a hot topic recently, driven by the flourishing tourism and the improvement of people’s living standard. The research history on assessment of bioclimatic comfort conditions, which may date back almost a century, is divided into three peroids based on a detailed survey of literature related to this topic over the past century. The infulential assessment models in each period are introduced. The historical background, basic idea and applicable conditions for each model are described in detail. The research shows that: ①bioclimatic comfort assessment models have been evolved from simple empirical models limited to space and time into complicated, impersonal, and universal energy balance models, which shows the trend of sophistication and objectivity; ②Today, empirical models are still widely used for the assessment of comfortable climates in China, and thus it is important to select the appropriate ones to make sure they are good for use for a study area or in a particular season; ③there are some problems calling for immediate resolution, such as to develop universal assessment models as well as to explore fine scale assessment techniques; ④the evaluation on featured comfortable climates, which might expand the study area of comfortable climates assessment, is an important research direction in the future.  相似文献   
63.
To answer the requirement of the European Commission's Water Framework Directive (WFD) for biological-effects endpoints to classify the ecological health of aquatic ecosystems, we propose the biomarker response index (BRI). The BRI, based on a suite of biomarkers at different levels of biological response at the individual level, provides an integrated relative measure of the general health status of coastal invertebrates. Using the BRI, the health of mussels (Mytilus edulis) from 10 estuaries classified by the Environment Agency of England and Wales under the WFD was compared. Eight sites were healthier than predicted and two showed a similar health status to that of the predicted point-source pollution risk classification. Results indicate that the BRI offers a potential measure of organism health that can be used in monitoring under the WFD as an additional aid to reduce uncertainty in defining risk classification and to provide better evidence of existing impact.  相似文献   
64.
A critical review of approaches to aquatic environmental assessment   总被引:1,自引:0,他引:1  
As demands on aquatic resources increase, there is a growing need to monitor and assess their condition. This paper reviews a variety of aquatic environmental assessments, at local, national, international and global scales and finds confusion in the terminology used to describe assessments. In particular the terms 'ecosystem' and 'integrated' are often misused resulting in lack of clarity. Therefore, definitions of some assessment terminology are suggested, consolidating existing proposals and simplifying future applications. A conclusion from the review is that a new classification system is required. The categorisation system proposed builds on preliminary work of the International Council for the Exploration of the Sea (ICES). Assessment classification is based on the environmental components considered, methodologies and nature of the linkages between components, and the inclusion or exclusion of socio-economic factors. The assessment terminology and categorisation system provided could in future simplify the way that assessments are defined and used to inform development of management strategies.  相似文献   
65.
The river Rhine has lain under considerable anthropogenic stress of its water quality for 100 years. As early as 1905 the first results of studies of the plankton in the Rhine were published. Due to the long residence time of the water a real potamoplankton can develop and at the end of the Lower Rhine it reaches its highest density. The paper consists of two parts. At first an overview is given about the history of plankton studies in the Rhine. The second part is the presentation of results from a monitoring at the Lower Rhine from 1979 to 2004.First systematic studies started at the beginning of the 20th century at the beginning of pollution. Our studies started during a phase of recreation from extreme pollution and eutrophication. Samples were taken at four stations: Bad Honnef, km 640, entrance to North Rhine-Westphalia, Düsseldorf, km 732, Duisburg, km 792 downstream large industrial effluents and big cities, Kleve-Bimmen, km 865 at the border to the Netherlands.In the 1970s nutrients were high, especially phosphate 0.65 mg PO4-P L−1 in 1979. After 1980 phosphate dropped to 0.11 mg PO4-P L−1 in 2004 (mean values of the growing season). Ammonia was reduced from about 0.52 (1979) to 0.02 (2004) mg NH4-N L−1. Nitrate remained between 3.72 (1989) and 2.26 (2004) mg NO3-N L−1 at a relatively high level. Oxygen concentrations were very low during the 1960s and 1970s, sometimes only 4 mg L−1 O2. During our studies the oxygen increased up to 9 mg L−1 O2 with a tendency to 11 mg L−1 O2 in the last years. Chlorophyll a was estimated to be between 59 (1979) and 31μg L−1 (1986) with short peaks up to 170 μg L−1 (1989). Since 1992 the mean values have varied between 30 (1993) and 21 μg L−1 (2004).The floristic phytoplankton composition is characterised by the dominance of the centric diatom Stephanodiscus hantzschii. Other diatoms like Skeletonema subsalsum, Skeletonema potamos and Asterionella formosa were regularly present in smaller quantities. The second dominant group was coccale green algae. During the 1980s they formed up to 35% of the biomass. Since the 1990s their contribution to the phytoplankton became much smaller. This change corresponds with the increase of wastewater treatment and the diminution of nutrients. All the other groups of algae were present in minor quantities. During the time of higher trophy in the 1970s and 1980s the phytoplankton formed two peaks, in recent years only one peak has developed, depending on different flow conditions during the growing season and lower trophic state in the upstream parts of the river.Excellent correspondence exists between cell number, biovolume and chlorophyll a content and the results of delayed fluorescence (DF) measurement. The trophic status in the Lower Rhine may be estimated as (moderate) eutrophic. The ecological status of the phytoplankton is good based on the requirements of the European Water Framework Directive (WFD).The zooplankton consists mainly of rotatoria and larvs of Dreissena polymorpha. Grazing on phytoplankton seems to be mainly due to the large quantities of benthic Dreissena and the newly introduced mussel Corbicula.  相似文献   
66.
兰州附近的庄浪河断裂和白银白杨树沟断裂是对兰州市地震安全有一定影响的晚第四纪活动断裂,但沿断裂发生的中强破坏性地震较为复杂甚至不明确。如何评价西部地区此类断裂的最大潜在地震震级及其危险性是地震中长期预测和地震区划研究中较为重要的问题之一。本文借鉴闻学泽等(2007)对中国大陆东部中-弱活断层潜在地震最大震级评估的思路,建立了兰州地区最大地震震级Mmax与断层小区震级-频度关系参数at/b值之间的经验公式;并采用经验公式外推得到庄浪河断裂和白杨树沟断裂的震级上限Mu分别为MS6.9、6.3,进而评估了这两条断裂的地震平均复发间隔和发震概率。  相似文献   
67.
喀斯特地区的水资源承载力评价研究——以贵州省为例   总被引:8,自引:6,他引:2  
周亮广  梁虹 《中国岩溶》2006,25(1):23-28
喀斯特地区水文运动规律特殊,生态环境脆弱,其水资源承载力也不同于非喀斯特地区。本文从喀斯特地区的水资源承载力入手,选取了供水模数、需水模数、水资源开发利用程度、人均供水量、工业用水重复利用率、耕地灌溉率、生态环境用水率等评价指标,并用多目标灰色关联投影法对贵州省各地区的水资源承载力状态进行了合理排序。最后对人口、GDP、水资源量和喀斯特面积与评价结果进行了灰色关联度分析,得出以上四因素与喀斯特地区的水资源承载力具有一定的关系,其关联程度大小顺序为: 水资源量> 人口> GDP> 喀斯特分布面积;喀斯特分布面积对其水资源承载力具有一定程度的影响,喀斯特地区经济发展的落后导致其经济发展与水资源承载力关系不明显; 随着经济技术水平的提高,喀斯特分布面积对水资源承载力的影响将逐渐减小。   相似文献   
68.
亚洲季风降水的多模式模拟结果分析   总被引:2,自引:2,他引:0  
利用参加政府间气候变化委员会(IPCC)第四次评估报告(AR4)的多个大气模式(包括中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室新发展的全球格点大气模式GAMIL)的AMIP-II(大气模式比较计划-II)积分的集合平均结果(MMEA),研究了当前大气模式对亚洲季风降水的平均模拟能力,同时也评估了GAMIL的模拟水平。对多年平均冬夏季降水的模拟研究发现:MMEA和GAMIL对冬季降水的模拟好于夏季。与以往的结果相比,MMEA对夏季印度洋和西太平洋地区降水的模拟改进不明显;部分模式能够模拟出夏季东亚副热带地区从中国东海到中太平洋的带状梅雨降水,但大部分模式的模拟强度还不够。可以看出GAMIL除了冬季印度洋和夏季菲律宾模拟的降水稍弱外,与MMEA的结果很接近。降水场的误差与环流场的误差对应。此外,作者还研究了降水的年际变化和季风爆发撤退过程的模拟能力。MMEA与观测在印度季风区降水的相关系数不如在东亚热带和东亚副热带季风区的好。各模式冬季的相关系数一般好于夏季,特别是东亚热带季风区冬季的相关系数普遍较高,而印度季风区夏季的相关系数普遍较低。MMEA对标准差的模拟并不总比单个模式的好。各个模式对东亚热带季风区冬季的降水距平同号率和降水距平百分率模拟得最好。季风爆发、撤退时降水推移的模拟也还有待于进一步提高。  相似文献   
69.
This paper deals with detailed analysis of the fiasco created by the Tehri High Dam in Uttarakhand, India, particularly in terms of resettlement and rehabilitation of the local inhabitants. Aspects pertaining to the environmental issues are also discussed. Currently, the river valleys in Uttarakhand state of India are the targets of increasing hydroelectric projects. Virtually all rivers are being exploited for generating environmental friendly power. Having being learned the hard lesson from Tehri Dam, it has been decided to opt for such schemes in which comparatively little submergence and tempering with the fragile eco-systems is involved.However, our observations suggest that even in such schemes if due care is not taken they may turn out to be a failure.  相似文献   
70.
金江军  潘懋  徐岳仁 《内陆地震》2007,21(2):135-141
从危险性评价、易损性评价以及防灾减灾能力评价3个方面阐述了城市地震灾害风险评价内容.回顾了地震灾害风险评价研究进展,指出了现有评价方法的不足.提出了基于地震小区划的城市地震危险性评价方法、基于城市用地类型的城市地震易损性评价方法以及基于专家打分法的城市防震减灾能力评价方法.最后设计了城市地震灾害风险评价流程,并给出了城市地震灾害风险区划算法.  相似文献   
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