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91.
The annual averages (1986–1997) of pH are analysed for the most important European Monitoring and Evaluation Programme stations in Europe. The first objective is to discover the different temporal patterns and trends for the pH. To do this, a cluster analysis is developed. The trends are analysed by linear regression for the annual averages. In general, the pH shows an increasing trend significant at 0.05 level and the annual change ranging from +0.01 to +0.05 pH‐units per year for the different clusters obtained. The second objective is to examine the spatial variability of pH in precipitation through the use of principal component analysis. Six statistically significant modes of variability are obtained for the pH which represent the 84.5% of the total variance. 相似文献
92.
Samuel Assembe-Mvondo 《国际发展与全球生态学杂志》2013,20(4):217-227
Sustainable forest management (SFM) has become a major focus for the international community. This is because of the multifunctional importance of forest resources for the entire planet, namely ecological, socio-economic, cultural and climatic balance. General awareness of forest importance unfortunately coincides with the observed increase in threats, especially anthropogenic, to this world heritage. To tackle the continuing deforestation and degradation, the international community, through the United Nations Forum on Forests (UNFF) and its predecessors, has attempted to adopt an international convention on SFM based on the 15 Rio Declaration principles. The limited success of international negotiations aimed at the adoption of such an instrument leads us to seek an alternative within international law theories, through analysis of the relationship between states practice in SFM and customary international law. To this end, this paper focuses on the practice of Central African States in sustainable forest management, especially statement of principles, sub-regional treaty and domestic legislation. The analysis shows that their practice fulfils all the requirements in order to be regarded as regional custom. Therefore, principles and state practices of SFM can thus be considered legally binding for this sub-region, despite some major implementation shortcomings. 相似文献
93.
Animals in the Himalayan region are reared basically to supplement the family income and sustain crop production, and constitute an important component of the rural economy of the region. Given the ecological importance of the livestock production system in terms of intrinsic values as a life support system for local people and a contribution towards sustainable agriculture through its role in the maintenance of soil fertility, the present study was conducted. This paper describes and assesses the current status of livestock production systems, monetary input/output, status of available forest resources, current level of pressure on the livestock production system and recommends strategies for sustainable development of a livestock production system in the Rawain Valley of Central Himalaya. 相似文献
94.
欧洲的恶臭污染法规及测试技术进展 总被引:1,自引:0,他引:1
欧洲城市中人口密度的增加导致了严重的恶臭污染,几百年来,各种有关恶臭污染的法规相继出台。在过去的30年中,恶臭测试方法有所发展,人们不再轻信环境健康工作者的主观判断,而是将恶臭测试推向定量化的轨道。根据恶臭排放测试,扩散模式以及恶臭标准(以定量恶臭性质的影响研究为基础,确定恶臭污染的可忍受程度),荷兰率先推动了恶臭量化管理趋势。恶臭标准根据各行业的恶臭污染的具体程度制定。嗅觉计测试臭气浓度是一项可靠的技术,目前已经写入欧洲标准(EN13725:2003),将嗅觉计测试法和日本的三点式比较臭袋法进行比较,发现结果具有显著的一致性。嗅辨员的严格筛选也是促成其一致性的关键因素。 相似文献
95.
Fine root decomposition is an important way in which nutrients are returned to plantation soil; thus, further study of this process will be helpful for understanding material cycling in forest ecosystems. We investigated a Toona sinensis plantation in the central Sichuan hilly region using litter bags containing T. sinensis fine roots to evaluate the dynamics of fine root decomposition and nutrient release for one year in forest gaps of 50 m2 (L1), 100 m2 (L2), and 150 m2 (L3). The results showed that T. sinensis fine root decomposition was fastest in the first 90 days. As time passed, the decomposition rate slowed. One year later, the residue rate was 75.44%, 73.92%, and 72.07%, respectively. The fine root decomposition rate of L3 was greater than that of L2, which was greater than that of L1. During fine root decomposition, the dynamics of the fine root nutrient concentrations changed. C, P, and K concentrations of the fine roots declined in forest gaps, while N, Ca, and Mg concentrations increased overall in the fine roots. In conclusion, forest gaps had effects on the fine root decomposition and nutrient release of T. sinensis, and different sized forest gaps produced different results. © 2018 Science Press. All rights reserved. 相似文献
96.
欧洲酸雨控制历程及效果综合评述 总被引:4,自引:0,他引:4
在分析大量文献资料的基础上,综合评述了欧洲酸雨发展和控制的主要历程. 20世纪70年代以来,欧洲酸雨控制主要经历了EMEP建立与达成共识,CLRTAP公约形成与实施平均减排方针,基于临界负荷与生态敏感性制定减排策略,以及多污染物协同控制与追求多重环境效应等4个发展阶段,并取得了显著的控制效果. 1980—2007年,欧洲硫排放减少了84%,NOx排放减少了37%;大气中ρ(SO2)从10.32 μg/m3降至1.26 μg/m3,ρ(NO2)从10.38 μg/m3降至7.15 μg/m3;欧洲降水酸度呈不断下降的趋势. 最后,基于欧洲酸雨控制先进经验的分析,结合实际情况提出了未来我国酸雨控制建议. 相似文献
97.
Rafik Absi 《Environmental Fluid Mechanics》2008,8(4):389-394
In a recent paper published in this journal, Bonakdari et al. (Environ Fluid Mech 8:1–17, 2008) presented a new formulation
of the vertical velocity profile in the central portion of steady fully developed turbulent open-channel flows which is based
on an analysis of the Navier–Stokes equations. The predicted mean streamwise velocity profiles presented by the authors represent
dip phenomenon (maximum velocity below the free surface). The discusser would like to point out some contradictions and an
error in the main demonstration. This error appears in the right-hand side term of the main Eq. 22 (Environ Fluid Mech 8:1–17,
2008) in the parameter α. Our corrected demonstration shows that α is equal to and not to as obtained by the authors (Environ Fluid Mech 8:1–17, 2008). The values of α used by the authors are under-estimated by 1, this difference has a significant effect on velocities and therefore will involve
a difference between measured and predicted velocity profiles. Finally, the assumption of at the free surface is in contradiction with predicted velocity profiles. 相似文献
98.
在对大连市凌水地区实施集中供热前后的环境效益进行定性分析比较的基础上,应用环境经济学的费用效益分析方法,对集中供热的环境效益进行了效益定量化估算,结果表明:实行区域集中供热联片取暖10年后投资费效比为1∶3.3。 相似文献
99.
On the influence of faulting on small-scale soil-gas radon variability: a case study in the Iberian Uranium Province 总被引:2,自引:0,他引:2
In order to evaluate the influence of faulting on the variability of geogenic radon at detailed scale (1:2000), data on gamma ray fluxes, U and Th concentrations in rocks, radon in soil-gas and radon in groundwater were collected in three target areas on the Oliveira do Hospital region (Central Portugal). This region stands on the Iberian Uranium Province, and is dominantly composed of Hercynian granites and metasedimentary rocks of pre-Ordovician age, crosscut by faults with dominant strike N35°E, N55°E and N75°E. Radiometric anomalies are frequent, associated with faults of the referred systems and metasedimentary enclaves; the analytical data confirms that these anomalies are produced by local high uranium contents in rocks and fault-filling materials (n = 34, range 13-724 ppm), while other radiogenic elements are relatively constant (e.g. Th 4-30 ppm). Radon concentration in soil can be extremely high, up to 12,850 kBq m−3 (n = 215), with a large proportion of results above 100 kBq m−3. Unsurprisingly, groundwater also shows high radon concentrations, with observed values in the range 150-4850 Bq.L−1 (n = 17). From the results it is concluded that metasedimentary enclaves, as well as faults, can accumulate uranium from circulating fluids, and as a consequence, strongly locally enhance geogenic radon potential. Due to this fact, for the purpose of land use planning in such uranium-enriched regions, very detailed geological mapping is needed to precisely recognize radon high risk areas. A correlation between radon concentration in soil or in groundwater and gamma ray fluxes was established pointing to the possible use of these fluxes as a first step in assessing geogenic radon potential, at least to geological setting similar to the study area. 相似文献
100.
本文介绍了碳金融的定义以及中国构建完善碳金融体系的背景,指出我国的CDM市场虽然是全球最大的CDM市场,但碳金融还处于起步阶段,缺乏国际CERs定价权,CDM项目存在巨大的风险,这些问题亟需解决。中国的银行业作为中国金融机构的主要组成部分,在构建完善的碳金融市场上起到了十分关键的作用。分析了目前中国银行业参与碳金融的现状及存在的问题,提出了中央银行和中国商业银行介入碳金融的方法。中央银行应与商业银行相互配合使中国的碳金融市场尽快发展和完善。 相似文献