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41.
上海城市二氧化碳排放空间特征   总被引:1,自引:0,他引:1  
构建上海1 km CO2排放网格,分析市域(UB1)、市辖区(UB2)、建成区(UB3)和城区(UB4)4个城市范围的CO2排放特征。上海市域CO2排放空间格局是以中心城区为核心,排放水平向外递减,形成了3个梯度。空间自相关分析表明,排放在空间上存在显著的集聚效应,部分地区高强度的经济活动和能源活动对周边区域的排放有显著影响。UB4是上海城市的最佳表征,2007年UB4内CO2排放达到1.89亿t,人均排放12.04 t;UB4排放占UB1排放的75.40%,UB1人均排放比UB4人均排放高12%。上海城市化和工业化在空间上的高度重合,导致高排放源集聚于UB4内,形成UB4的高排放特征。个别网格的排放量已经占到区域或者城市总排放量的10%~20%;前10高和前100高排放网格,其累积排放总量分别占据了3个城市范围(UB1、UB3和UB4)总排放量的60%和80%以上。  相似文献   
42.
锶同位素地层学是化学地层学的组成部分 ,简要介绍重庆市秀山县溶溪乡罗家沟寒武系剖面海相碳酸盐的锶同位素分析结果 ,建立了该剖面的锶同位素演化曲线 ,并与 Gao及 Denison等的同期锶演化曲线作了对比 ,秀山寒武纪锶同位素演化曲线与其他两条同期曲线有较大相似性 ,据此提出了秀山寒武系剖面部分主要年代地层界线的参考意见 ,并简述了寒武纪全球海平面变化的概况。  相似文献   
43.
Based on the seismic station data sets from Sichuan and Yunnan provinces, we employed a multi-step seismic location method (Hypo2000 + Velest + HypoDD) to precisely locate the 7,787 earthquakes that occurred during 2010-2015 along the eastern boundaries of the Sichuan-Yunnan rhombic block, namely from southern Dawu to the Qiaojia segment. The final results show that location precision is greatly advanced and epicenter distribution exhibits good consistency with the linear distribution of the seismic faults. Earthquake distribution is quite intensive at the intersection region in the southern segment of the Xianshuihe fault, the Anninghe fault zone, the Xiaojinhe fault zone and the Daliangshan fault zone to the east. The depth profile of seismicity shows a clear stepwise activity along the active seismic fault zones. The profile crossing the faults of the Xianshuihe, Anninghe, and Daliangshan presents a complex interaction among faults near the multiple faults intersection region, Shimian, where the earthquakes are obviously divided into two groups in depth. Earthquakes are very rare at the depth of 15km-20km, which is consistent with the region of the plastic rheology between 14km-19km calculated by Zhu Ailan et al.,(2005).  相似文献   
44.
透岩浆流体成矿体系   总被引:35,自引:10,他引:35  
根据透岩浆流体成矿理论,熔浆体系与含矿流体体系可以看作是两个相互独立的地质体系,它们因相互需要而耦合在一起形成一个复杂的混合体系。当熔浆与流体发生解耦时,可以在不同的边界条件下发生不同类型的成矿作用。因此,可以将透岩浆流体成矿体系进一步划分成正岩浆成矿体系、接触带成矿体系、远程热液成矿体系和火山热液成矿体系。如果熔浆具有很强的流体圈闭能力,所有的含矿流体都将被封存在岩浆体内,并随着岩浆的固结而析出成矿物质,形成正岩浆矿床。当岩浆具有较高的渗透率且含矿流体逸出岩浆体时,如果岩浆的直接围岩具有较强的捕获成矿物质的能力,即发生接触带成矿作用。否则,含矿流体将在岩浆热驱动下远离岩浆体,形成远程热液矿床。如果有利的流体通道直达岩浆体,含矿流体甚至可以喷出地表或其附近,形成火山热液矿床或水底喷流沉积矿床。这种理论分析似乎与许多成矿事实相吻合,可以有效地指导区域成矿预测和矿床勘探。  相似文献   
45.
为了定量获取防洪保护区在多洪源和复杂边界条件下的溃堤洪水风险信息,以非恒定流控制方程为理论基础,建立了多洪源一维河网水动力学模型和防洪保护区二维洪水演进模型,利用溃坝模型实现河道与保护区的耦联,并采用局部网格加密和相似建筑物模拟等方法处理保护区内道路等复杂边界的导阻水作用。利用所建模型模拟了长江、汉江和东荆河3种不同洪水来源, 在4种不同位置溃堤情况下汉南至白庙长江干堤防洪保护区的洪水淹没情景,采用基于淹没水深的损失率关系法对比分析了4种计算方案的淹没面积、经济损失和受灾人口。结果表明:模型构建合理、稳定性和适应性好,复杂边界对洪水演进过程影响明显,不同洪源溃堤情形的风险信息差异较大;在计算条件下,以长江发生1954年型300年一遇洪水向新溃口情形下的淹没损失最严重,其淹没面积达3 790 km2,受灾人口为196.8万人,经济损失约802亿元。研究成果可为洪水风险管理与避洪转移决策提供有力的技术支撑。  相似文献   
46.
梅仕龙  史晓颖 《地球科学》1999,24(2):167-172
全球层型剖面和点(GSSP)应尽可能在层序界面的整合部位,从而将地层的自然界线、层 GSSP有机地结合起来,使年代地层界线可在野外识别和追索,层序地层可以做为岩石地层和年代地层的而独立存在,构成新的三重地层分类,地层界线的优化应尽可能与层序界面相结合,以使其具有更强的可损伤性,随着层序地层学的发展及其在地层学和概念上取得了的创新和突破,有在新的地层学体系指导下建立新一代年代地层表,从而更加客观地反  相似文献   
47.
王宇 《中国岩溶》2019,38(6):823-830
岩溶地区地表水流域与地下水流域边界的分异形式有三类,即:地表分水岭与地下水流域边界在平面分布上基本一致;地表分水岭超出了地下水流域边界;地下水流域边界超出了地表分水岭。岩溶区地表水与地下水耦合流域的顶界为地表水流域的水面及下垫面,底界为浅循环潜水含水层或潜水—承压含水层下伏的隔水层顶面,在大厚度岩溶含水层分布区,可以弱岩溶发育带的顶面作为底界。其中地表水与地下水两个子系统间的次级边界,为地表水流域的下垫面。结合专门调查(勘查)评价和区域调查评价的特性,提出评价单元划分的原则及方法。这有助于在新一轮自然资源调查评价中,以流域为单元系统地开展水资源及环境调查评价,实行地表水和地下水资源及环境的统一管理。  相似文献   
48.
Voronoi tessellation, and its dual the Delaunay triangulation, provide a cohesive framework for the study and interpretation of phenomena of geographical space in two and three dimensions. The planar and spherical solutions introduce errors in the positional accuracy of both Voronoi vertices and Voronoi edges due to errors in distance computations and the path connecting two locations with planar lines or great circle arcs instead of geodesics. For most geospatial applications the introduction of the above errors is insignificant or tolerable. However, for applications where the accuracy is of utmost importance, the ellipsoidal model of the Earth must be used. Characteristically, the introduction of any positional error in the delimitation of maritime zones and boundaries results in increased maritime space for one state at the expense of another. This is a situation that may, among others, have a serious impact on the financial activities and the relations of the states concerned. In the context of previous work on maritime delimitation we show that the Voronoi diagram constitutes the ideal solution for the development of an automated methodology addressing the problem in its entirety. Due to lack of a vector methodology for the generation of Voronoi diagram on the ellipsoid, the aforementioned solution was constrained by the accuracy of existing approaches. In order to fill this gap, in this paper we deal with the inherent attributes of the ellipsoidal model of the Earth, e.g. the fact that geodesics are open lines, and we elaborate on a methodology for the generation of the Voronoi diagram on the ellipsoid for a set of points in vector format. The resulting Voronoi diagram consists of vertices with positional accuracy that is only bounded by the user needs and edges that are comprised of geodesics densified with vertices equidistant to their generators. Finally, we present the implementation of the proposed algorithm in the Python programming language and the results of two case studies, one on the formation of closest service areas and one on maritime boundaries delimitation, with the positional accuracy set to 1 cm.  相似文献   
49.
A land stratification of the French territory had been previously performed based on time series of vegetation and texture indices. This stratification led to 300 radiometrically homogenous regions that were considered as land units (LUs). In this paper, we present a quantitative analysis of the LUs, with the aim of testing if these LUs are linked to landscape. In this sense, an evaluation of their thematic meaning in terms of environmental variables and land cover was performed. In order to achieve this, we first conducted a statistical analysis at national scale using a set of environmental variables and land cover by means of Moran’s autocorrelation index and Spearman rank correlation index. Second, to analyze the quality of the boundaries between neighboring LUs, we developed a method based on the Spearman rank correlation index calculated on test areas across the boundaries. The first analyses showed that the most explanatory variables of the LUs were land cover, topography and parent material. The boundaries analysis was applied at a regional scale (Pyrenean region), and showed that 89% of the boundaries were well explained by the land cover compositions. The results obtained support the hypothesis that time series of broad resolution remote-sensing images can capture landscape identities and produce LUs maps that have an environmental and land occupation sense.  相似文献   
50.
Evidence for partial melting along subgrain boundaries in quartz and plagioclase is documented for rocks from the Lost Creek Gneiss of the Llano Uplift, central Texas, the Wet Mountains of central Colorado, and the Albany-Fraser Orogen, southwestern Australia. Domains of quartz or plagioclase crystals along subgrain boundaries are preferentially involved in partial melting over unstrained domains of these minerals. Material along subgrain boundaries in quartz and plagioclase has the same morphology as melt pseudomorphs present along grain boundaries and is commonly laterally continuous with this former grain boundary melt, indicating the material along subgrain boundaries can also be categorized as a melt pseudomorph. Subgrain boundaries consist of arrays of dislocations within a crystal lattice, and unlike fractures would not act as conduits for melt migration. Instead, the presence of former melt along subgrain boundaries requires that partial melting occurred in these locations because it is kinetically more favorable for melting reactions to occur there. Preferential melting in high strain locations may be attributed to strain energy, which provides a minor energetic contribution to the reaction and leads to preferential melting in locations with weakened bonds, and/or the presence of small quantities of water associated with dislocations, which may enhance diffusion rates or locally lower the temperature needed for partial melting.  相似文献   
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