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131.
The functional relation between theδ18O values in the shell of gastropod Gyraulus sibirica and the air temperature in the warm half-yearly period, and that between Sr/Ca ratio and the precipitation in the warm half-yearly period were established by calibrating the δ18O and δ13C values, Sr/Ca ratio and Mg/Ca ratio in the shell Gyraulus sibirica, as well as the total organic carbon (TOC) and its δ13C values in the Xingcuo Lake sediment in the eastern Tibetan Plateau. The sequences of air temperature and precipitation in the last 200 years in the region were quantitatively recuperated on this basis. The results showed the following: (i) There was a negative correlativity between Sr/Ca ratio and the precipitation in the warm half-yearly period, its correlation coefficient was 0.86. (ii) There was an obviously positive correlativity between indexδ18O and the running average temperature in the warm half-yearly period, its correlation coefficient was 0.89. (iii) Evolution of the air temperature and the precipitation in the last 200 years can be divided into three phases distinctly. The precipitation in the later mid-19th century was 220 mm higher than that today; the air temperature in the warm half-yearly period was 2℃ lower than that of the present. The precipitation in the minimum air temperature period of the early 20th century was below that today by 60 mm, and the air temperature in the warm half-yearly period was 3.4℃ lower than that today. (iv) An evidently warming and drying trend existed in the last five decades. 相似文献
132.
133.
INTRODUCTIONTheproxyofstableoxygenisotopeinlakecarbonateisidealforthereconstructionofpastcli mate (Gasseetal.,1 991 ;Wu ,1 996;Zhangetal.,1 994 ) .Asidefrombeingimpactedbylake watertemperature ,thevalueofδ18Oinlakecarbonateisalsocontrolledbythatofambientlakewa ter.High… 相似文献
134.
自七十年代后期大功率短导线激电法推广以来,激发极化法的使用迈进了小比例尺普查阶段,成了区域找矿评价的重要方法之一。近几年来,区域激电普查成果不仅在成矿带的找矿远景评价上得到了广泛应用,而且在基础地质研究中的效果也日益显著。无论在地质构造填图上,还是在开展间接找矿方面都收到了不同程度的成效。 相似文献
135.
Data show that carbon emissions are increasing due to human energy consumption associated with economic development. As a result, a great deal of attention has been focused on efforts to reduce this growth in carbon emissions as well as to formulate policies to address and mitigate climate change. Although the majority of previous studies have explored the driving forces underlying Chinese carbon emissions, few have been carried out at the city-level because of the limited availability of relevant energy consumption statistics. Here, we utilize spatial autocorrelation, Markov-chain transitional matrices, a dynamic panel model, and system generalized distance estimation(Sys-GMM) to empirically evaluate the key determinants of carbon emissions at the city-level based on Chinese remote sensing data collected between 1992 and 2013. We also use these data to discuss observed spatial spillover effects taking into account spatiotemporal lag and a range of different geographical and economic weighting matrices. The results of this study suggest that regional discrepancies in city-level carbon emissions have decreased over time, which are consistent with a marked spatial spillover effect, and a ‘club' agglomeration of high-emissions. The evolution of these patterns also shows obvious path dependence, while the results of panel data analysis reveal the presence of a significant U-shaped relationship between carbon emissions and per capita GDP. Data also show that per capita carbon emissions have increased in concert with economic growth in most cities, and that a high-proportion of secondary industry and extensive investment growth have also exerted significant positive effects on city-level carbon emissions across China. In contrast, rapid population agglomeration, improvements in technology, increasing trade openness, and the accessibility and density of roads have all played a role in inhibiting carbon emissions. Thus, in order to reduce emissions, the Chinese government should legislate to inhibit the effects of factors that promote the release of carbon while at the same time acting to encourage those that mitigate this process. On the basis of the analysis presented in this study, we argue that optimizing industrial structures, streamlining extensive investment, increasing the level of technology, and improving road accessibility are all effective approaches to increase energy savings and reduce carbon emissions across China. 相似文献
136.
在国家大力推进生态环境治理和生态修复的背景下,矿山周边的农户作为环境破坏的受害者和生态修复的主要参与者,其参与意愿的高低关系到政府环境治理政策能否发挥良好作用。以大宝山尾矿区为例,构建包括价值感知、政策感知和禀赋感知对亲环境行为意愿的影响模型,探讨环境感知对农户亲环境行为意愿的影响机制。研究发现:1)价值感知包括经济和生态2个维度,且均会对农户的亲环境行为意愿产生直接正向影响;禀赋感知包括精力和能力2个维度,且均会对其亲环境行为意愿产生影响;政策感知包括感知政府、感知矿企和邻居朋友态度3个维度,对其亲环境行为意愿不产生直接影响,但可通过价值感知和禀赋感知对其亲环境行为意愿产生间接影响。2)收入的提高、感知矿企的态度以及精力和能力的感知是农户亲环境行为意愿的重要影响因素。政府需将传统手段与新型网络平台结合,加强环境治理多渠道宣传、就业能力培养和邻里示范等,以提升农户亲环境行为意愿。 相似文献
137.
月球角砾岩是月球陨石的代表性样品,含有多来源的岩屑,是揭示月球内-外动力演化历史的重要窗口。本文对Bechar 003、NWA 13788和NWA 11110月球陨石中的岩屑开展了岩相学、矿物学及地球化学分析,通过岩相、矿物成分、全岩主微量元素等岩石地化综合分析,旨在厘清这3块样品中岩屑的类型、来源与成因机制。结果表明,3块陨石内部的斜长辉长质冲击熔融岩屑、微斑熔融角砾岩屑、以及辉长质斜长岩屑的初始物质由均是月海玄武岩与月球高地岩石的混合物,不同初始物质成分的岩屑表明月表经历了冲击事件,并且冲击事件发生在月表的不同位置,冲击事件造成月球高地岩石与月海玄武岩或非月海溅射物的混合。 相似文献