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991.
综合考虑矿物,元素地球化学和孢粉等多方面的资料,对珠江口北岸SX97孔揭示的7000a B.P.以来的气候环境演化提出了一种5阶段划分方案。这种阶段性在SX97孔的各项指标上均有很好的对应,也与华南地区基于海岸沙丘,海滩岩和海相沉积地层等的早期研究成果能较好地对应。在此基础上,初步探讨了气候环境变化中的流域响应,发现SX97孔揭示出气候环境变化中很有很好的流域响应。如当气候环境偏湿偏热时,流域风化作用更加强烈,有很更多的铁元素流失,同时流域植被更发育,对降水有更好的缓冲作用,导致河口沉积物中含有更的铁元素(包括二价铁和三价铁),更少石英矿物和更多粘土矿物,当气候环境偏干偏凉时则相反。 相似文献
992.
World-wide, people and governments are gradually becoming more aware of the potential environmental, economic and health effects of climate change and the need for governments to take action to mitigate such impacts. This was emphasised by the creation of the United Nations Framework Convention on Climate Change (UNFCCC), signed at the Rio Earth Summit in 1992. There has been much discussion on the greenhouse policy response of the commonwealth government of Australia, especially its stance taken at Kyoto in December 1997. Despite the recent nationalisation of Australia's state energy markets, due to Australia's federal political structure, much of the policy responsibility for energy and environmental issues rests with the states. Given these circumstances it is surprising that there has been relatively little academic focus on the energy policies of the states. This paper attempts to partially fill the policy analysis 'gap' by investigating the present environmental aspects of the energy policies of NSW and Victoria, implemented since the signing of the UNFCCC in 1992. NSW and Victoria are Australia's most populous states and are responsible for the bulk of the nation's greenhouse gas emissions with two very distinct policies. 相似文献
993.
Management of transboundary water resources: lessons from international cooperation for conflict prevention 总被引:3,自引:0,他引:3
Tensions over freshwater resources may become more frequent as pressures on water resources grow due to increased demand and variability of rainfall. Conflicts may take place between or within countries or between competing sectoral users. This paper focuses on institutional approaches for enhancing cooperation between countries for sustainable development of transboundary freshwater bodies and contributing basins. It is assumed that instead of being zones of conflict, shared water resources can provide a basis for cooperation and benefit–sharing provided that threats to the international waters are recognized and collaborative structures are created. The paper draws upon experiences gained within the international waters focal area of the Global Environment Facility, the main funding mechanism for countries to support the environmental management of transboundary water resources. Lessons for promoting peaceful cooperation for environmental management, benefit–sharing and sustainable use of transboundary freshwater resources are highlighted through examples from Africa, Central Asia and Latin America. Experience shows the importance of processes that bring together all sectors and actors whose actions affect the transboundary waterbody at regional, national and local levels. The development of a science–based diagnostic analysis is essential to identify the threats to the transboundary ecosystem and to break down the issues into manageable parts with the aim of developing a strategic action programme. Ensuring political commitment that can result in institutional, policy and legal reforms in the countries concerned is the key to sustainable development of the transboundary resource. 相似文献
994.
气候变化与人类活动干扰下塔里木盆地南缘地下水的变化及其生态环境效应 总被引:17,自引:11,他引:17
地质时期及历史时期以来塔里木盆地南缘气候变化,尤其是温度变化引起水文条件及河流水系变迁是导致地下水变化并由此造成绿洲演化的主导因素。百年尺度的气温波动不足以引起水资源状况明显的变化,人类活动是近几十年导致区域地下水及生态环境变化的主要因素,通过天然河道人工渠系化,平原水库建设以及枢纽工程上移,加速和促进了地表水资源的时空再分配,从而引起了地下水空间补给变化。山前砾石戈壁倾斜平原的补给量不断减少,而人工绿洲区地下水补给量则随地表引水量的提高不断增加。同时以天然河道渗漏补给为主转向以渠系、田间入渗为主。 相似文献
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996.
大兴安岭泥炭微量元素分布特征及其环境意义 总被引:6,自引:4,他引:6
采用原子吸收光谱和等离子体发射光谱等现代仪器分析方法对大兴安泥炭生趣剖面中Cu,Pb,Zn,Cd,Hg,Cr,Ni,Mn,Sr,Ba等12种微量元素进行了测定,结果表明,大兴安岭地区古莲,图强泥炭地和同一泥炭地沼泽泥炭发育的不同阶段,微量元素含量分布规律不十分明显,与俄国斯典型同类泥炭相比,Mn含量俄罗斯泥炭明显高于大兴安岭泥炭,Zn,Co,B含量大兴安岭泥炭明显高于俄罗期泥炭。 相似文献
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999.
Dawn J. Wright Elizabeth O'Dea Judith B. Cushing Janice E. Cuny Douglas R. Toomey 《Marine Geodesy》2003,26(1):73-86
During several decades of investigation, the East Pacific Rise seafloor-spreading center at 9°-10°N has been explored by marine geologists, geophysicists, chemists, and biologists, and has emerged as one of the best studied sections of the global midocean ridge. It is an example of a region for which there is now a great wealth of observational data, results, and data-driven theoretical studies. However, these have yet to be fully utilized, either by research scientists or educators. While the situation is improving, a large amount of data, results, and related theoretical models still exist either in an inert, noninteractive form (e.g., journal publications) or as unlinked and currently incompatible computer data or algorithms. Presented here is the prototype of a computational environment and toolset, called the Virtual Research Vessel, to improve the situation by providing marine scientists and educators with simultaneous access to data, maps, and numerical models. While infrastructure is desired and needed for ready access to data and the resulting maps via web GIS in order to link disparate data sets (data to data), it is argued that data must also be linked to models for better exploration of new relations between observables, refinement of numerical simulations, and the quantitative evaluation of scientific hypotheses. For widespread data access, web GIS is therefore only a preliminary step rather than a final solution, and the ongoing implementation of the Virtual Research Vessel (scheduled for final completion in 2004-2005) is a case study for the midocean ridge community to test the effectiveness of moving beyond the data-to-data mode towards data-to-models and data-to-interpretation. 相似文献
1000.