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651.
湖北省1981年以来不同时间尺度气温的变化 总被引:5,自引:0,他引:5
详细分析全省71站1981 ̄1994年与前20年不同时间尺度平均气温差值的时空分布特征后发现,80年代以来我省各地年均气温变化小,但相对地降温范围广,幅度大,且四季及逐月、甸格局发生重大调整,区域差异明显,其特点是冬久暖,夏久凉,春季前冷后暖,秋季反之、其中以夏凉春热最显著;鄂西山区四季均为负变温。 相似文献
652.
以盘塘红壤实验区为例,在阐明湘北环湖低丘红壤区土壤形成、类型及特性的基础上,提出了综合开发利用该区土壤资源的措施和途径。 相似文献
653.
Project appraisal and planning for overdeveloped countries: I. The costing of nonrenewable resources
Colin Price 《Environmental management》1984,8(3):221-232
In cost-benefit analysis, natural resources, like other factors of production, should be costed as a mixture of marginal social cost of exploiting additional resources and lost marginal social benefit of forgone alternative uses, according to the way in which extra resources are made available to a project. For a nonrenewable resource, changes in future marginal social cost and marginal social benefit are likely to add significantly to the immediate elements of cost, as successively less tractable resource stocks are exploited. Of the several reasons given for ignoring these future costs, the most plausible is that technological advance justifies a heavy discount on the future. However, neither historical nor logical arguments demonstrate the inevitability of efficacious technological advance. 相似文献
654.
刘虹 《中国人口.资源与环境》1996,6(2):31-35
江苏省南部地区是我国经济相对发达的区域,其基本特点是人口较多、资源利用程度相对充分、环境压力相对较大,在发展中需要转变经济增长方式,合理利用资源和保护环境.实现可持续发展。 相似文献
655.
针对南方红壤丘陵区农业资源利用的现状,以湖南省桃江县为例,应用灰色关联度模型定量分析了农业各部门产值对农业总产值的影响程度。结果发现,近50年来桃江县农业各部门的关联序列为:种植业(0.887 5)>牧业(0.760 2)>渔业(0.675 6)>林业(0.543 3)。种植业和牧业产值的变化对桃江农业总产值的波动起着主导作用。基于历史统计数据,利用灰色预测模型预测了2001~2005年5年内桃江县农业各部门产值的变化趋势。预测结果表明,各部门发展对农业总产值的关联度分别为:种植业(0.611 3)>渔业(0.358 7)>林业(0.347 6)>牧业(0.334 7)。比较两组关联序列可以清楚发现农业产业各部门的发展潜力。结合桃江农业资源和各部门的发展趋势,提出了桃江县农业结构优化调整的方向。 相似文献
656.
A. Parviz Koohafkan 《Natural resources forum》2000,24(2):69-81
Land degradation continues to be a major threat to local and national food security. With limited potential to develop new land, any increase in agricultural production must be sought largely through the better use of land already under cultivation. Concerns for the global environment associated with agriculture worldwide have also increased in recent years and require more coordinated efforts at global and national levels with decentralisation of activities at the local level.
This article presents an overview of land resources potential for food production, the processes and extent of land degradation and its economic and environmental costs and impacts, and highlights some macro-economic policies and institutional measures for the prevention of land degradation and rehabilitation of degraded lands. A people-centred programme is presented as a basis for decentralising activities for sustainable land use and land management. Finally, the need for better coordinated efforts of concerned UN, multinational agencies and NGOs for the implementation of Agenda 21 and related conventions is stressed. 相似文献
This article presents an overview of land resources potential for food production, the processes and extent of land degradation and its economic and environmental costs and impacts, and highlights some macro-economic policies and institutional measures for the prevention of land degradation and rehabilitation of degraded lands. A people-centred programme is presented as a basis for decentralising activities for sustainable land use and land management. Finally, the need for better coordinated efforts of concerned UN, multinational agencies and NGOs for the implementation of Agenda 21 and related conventions is stressed. 相似文献
657.
Ambrose Goicoechea Eugene Z. Stakhiv Fu Li 《Journal of the American Water Resources Association》1992,28(1):89-102
ABSTRACT: A research project was undertaken for the U.S. Army Corps of Engineers to determine the relative utility and effectiveness of four well-known multicriteria decision making (MCDM) models for applications in realistic water resources planning settings. A series of experiments was devised to examine the impact of rating and ranking procedures on the decision making behavior of users (e.g., planners, managers, analysts, etc.) when faced with situations involving multiple evaluation criteria and numerous alternative planning projects. The four MCDM models tested were MATS-PC, EXPERT CHOICE, ARIADNE, and ELECTRE. Two groups of analysts and decision makers were tested. One group consisted of experienced U.S. Army Corps planners, while the other was comprised of graduate students. Based on a series of nonparametric statistical tests, the results identified EXPERT CHOICE as the preferred MCDM model by both groups based largely on ease of use and understandability. ARIADNE fostered the largest degree of agreement within and among the two groups of individuals tested. The tests also lend support to the claim that rankings are not affected significantly by the choice of decision maker (i.e., who uses any of these MCDM models) or which of these four models is used. 相似文献
658.
659.
川西北地区位于青藏高原东南部,现有两栖爬行动物67种(亚种),其中两栖类28种,爬行类39种;珍稀、濒危种约占22.4%,经济意义大、有利用价值的种占29.8%,经济意义一般的种占47.8%。这些动物在科研、工艺、药用、维护生态平衡等方面均有一定意义。本文对这些动物的利用现状作了评价,并对资源保护提出5点建议。 相似文献
660.
Liu Jihan 《环境科学学报(英文版)》1991,3(3):99-104
By analyzing the cases in Taishan Mountain, Shandong Province and other tourist sites in China, this paper pointed out the problems in tourism management, such as resources damage, environment pollution, which are the result of tourism development, and are obstacles to the development. The paper also gave suggestion and practical ways to preserve tourism resources and environment. 相似文献