Progress of Tracing Fossil Fuel CO2 by Radiocarbon in Chinese Cities     

Weijian Zhou  Shugang Wu  Xiaohu Xiong  Peng Cheng  Peng Wang  Yaoyao Hou  Zhenchuan Niu  Hua Du  Ning Chen  Xuefeng Lu  Yunchong Fu  Lin Liu 《地球科学进展》1986,35(9):881-889

The main cause of increase in atmospheric CO₂ concentration is the carbon emissions from fossil fuel combustions and so on. Cities are regarded as the hot spots of carbon emissions. On the basis of obtaining the levels and spatial-temporal variation characteristics of atmospheric fossil fuel CO₂ （CO_2ff）， we can provide scientific data for government policy-making and international negotiations on carbon reductions. In the recent ten years， some important progresses have been achieved in the study of tracing urban atmospheric CO_2ff using ¹⁴C by Chinese scientists. The variation characteristics of urban CO_2ff at different temporal and spatial scales were obtained through the analysis of ¹⁴C in air， tree ring and annual plant samples. Our results show that the northern cities are the key points to reduce carbon emissions， and that the CO_2ff emissions can be reduced simultaneously by controlling atmospheric pollutant emissions， indicating a synergistic emission reduction. It was found that CO_2ff in Xi'an was mainly from local coal-burning emissions with the use of improved WRF-CHEM model and δ¹³C. Finally， the yearly CO_2ff traced by tree-ring ¹⁴C in Xi'an showed similar trends and amplitudes with the statistical data of carbon emissions， which indicates that the ¹⁴C tracing method and statistical method can be mutually validated to ensure the reliability of the data. In order to promote the ¹⁴C trace study to serve the national carbon emission reduction task， we suggest that the urban atmospheric Δ¹⁴CO₂ observation network should be established as soon as possible， and that this study should be enhanced with more scientists involved in it and more financial resources to support it.  相似文献   

Magnetotelluric soundings across the South Island of New Zealand: electrical structure associated with the orogen of the Southern Alps   总被引：1，自引：0，他引：1  

Malcolm Ingham 《Geophysical Journal International》1996,124(1):134-148

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一种改善MT低频数据质量的方法及其应用   总被引：2，自引：3，他引：2  

胡玉平  鲍光淑等 《地质与勘探》2002,38(3):46-48

电磁干扰是影响大地电磁测深方法（MT）数据质量的主要因素。目前，除从仪器电路上考虑压制50Hz的工业干扰外，主要的压制干扰的方法为近，远参考的ROBUST技术，它对高频电磁干扰或随机干扰有明显的压制作用。但在强干扰地区（通常具有很强的低频电磁干扰，如长，短脉冲和方波等低频干扰），低频数据的质量仍然很差，这是因为在低频数据处理时，强的低频电磁干扰使得级联分样后的数据发生了强的崎变，与实际的有用信号相差甚远，从MT时序数据出发，提出了应用小波变换的方法，重组低频干扰并加以消除，达到提高信噪比的目的，经实际资料处理证明，此方法效果明显。  相似文献   

喜马拉雅和青藏高原深剖面研究的进展   总被引：1，自引：0，他引：1       下载免费PDF全文

赵文津  黄立言  熊嘉育 《地球物理学报》1997,40(Z1):140-152

概述了1992─1996年中、美、德合作开展“喜马拉雅和青藏高原深剖面及综合研究”的主要进展，包括研究项目的提出、工作进展概况和取得的主要科学、技术成果；并对今后的工作提出了建议．  相似文献   

我国大地电磁测深研究新进展   总被引：32，自引：8，他引：32       下载免费PDF全文

王家映 《地球物理学报》1997,40(Z1):206-216

回顾了我国80年代中期以来大地电磁测深工作的进展，包括资料采集、数据处理和反演解释着重介绍了大地电磁测深法在石油、天然气构造普查勘探以及地壳和上地慢探测方面应用的情况．  相似文献   

水中大地电磁法测深   总被引：1，自引：0，他引：1  

柳建新  毛先成  张友山 《物探与化探》1997,21(1):74-76

水中大地电磁法就是采用远参考的方法在水面进行大地电磁法。本文结合作者的实际工作经验,介绍了在湖泊、沼泽等水域开展水中大地电磁测深法(MT法)的工作方法和取得高质量测深资料的措施,总结了方法实施工作中的一些经验和体会,为在大面积水域开展MT工作提供了依据。  相似文献   

Results of magnetotelluric and gravimetric measurements in western Nicaragua, Central America   总被引：1，自引：0，他引：1  

Sten-Åke Elming  Thorkild Rasmussen 《Geophysical Journal International》1997,128(3):647-658

Magnetotelluric and gravity data have been collected within a ca. 170 km long traverse running from the Pacific coast of Nicaragua in the west to the Nicaraguan Highland in the east. This part of Nicaragua is characterized by sedimentary rocks of the Pacific Coastal Plain, separated from the Tertiary volcanic rocks of the Highland by the NW-SE-trending Nicaraguan Depression. 2-D interpretation of the magnetotelluric (MT) data, collected at 13 stations, indicates four regions of high electrical conductivity in addition to the conductive coastal region. Two of these are associated with conducting sediments and pyroclastics in the upper part of the crust. Two other conductive structures have been defined at depth around 20 km and the one best defined is located below the depression. From the distribution of seismic events, volcanic activity in the depression and the similarity in geophysical characteristics with areas such as the Rio Grande Rift, this conductor is interpreted as a melt layer or a complex of magma chambers. Models of the upper lithosphere, constrained by the MT model, vertical electrical sounding (VES) data, seismic data and densities, have been tested using gravity data. A model that passes this test shows a gradual thickening of the crust eastwards from the Pacific coast. An anomaly centred over the depression is interpreted to have its origin in a thinning of the crust. In this model the melt layer is situated on top of the bulge of the lower lithosphere. A change in the composition of the crust, from the Pacific Coastal Plain to the Highland, is indicated from the change in character of the MT response and from the density distribution in the gravity model. This may support the hypothesis that the Pacific region is an accreted terrane. MT and gravity data indicate a depth to a resistive and high-density basement in the depression of ca. 2 km. On the basis of this, the vertical setting in the depression is estimated to be of the order of 2.5 km.  相似文献   

An interpretation technique for superimposed induction anomalies     

B. Siemon 《Geophysical Journal International》1997,130(1):73-88

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Audiomagnetotelluric investigations of shallow sedimentary basins in northern Sudan   总被引：1，自引：0，他引：1  

Heinrich Brasse  Volker Rath 《Geophysical Journal International》1997,128(2):301-314

Audiomagnetotelluric (AMT) investigations were carried out to study shallow sedimentary basins in northern Sudan and southern Egypt. Unlike recordings in settled areas, the natural variations (atmospherics) in the eastern Sahara were completely unperturbed by cultural noise, usually yielding very high data quality. Typical recordings and spectra are presented. The atmospherics show distinct daily variations, with maximum amplitudes in the local afternoon/night hours. As a sort of calibration, AMT measurements together with DC-resistivity and electromagnetic soundings were conducted at several groundwater boreholes. Under favourable conditions, a vertical anisotropy may be resolved by joint inversion of DCR and AMT data. The results of a case study in the Es Safya basin (NW Sudan) are presented. The investigations were aimed at determining basement depths and groundwater levels, as well as the direction and dip of major bounding faults. 2-D modelling and inversion revealed the overall conductivity structure of this shallow graben. The AMT method proved to be a valuable tool for a comparatively swift reconnaissance study of shallow structures.  相似文献   

Electrical resistivity model of the crust and upper mantle from a magnetotelluric survey through the central Pyrenees   总被引：2，自引：0，他引：2  

Jaume Pous  Juanjo Ledo  Alex Marcuello  Marc Daignières 《Geophysical Journal International》1995,121(3):750-762

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