利用FY-2C卫星资料估算太阳辐射研究     

梁益同  刘可群  夏智宏 《气象科技》2009,37(2):234-238

我国FY-2C气象卫星为估算到达地面的太阳辐射提供可靠的数据源。文章以华中3省（河声、湖北和湖南）为试验区,采用神经网络方法进行FY-2C资料太阳辐射的估算,并与统计方法结果进行比较。结果表明：①FY-2C资料可以用于太阳辐射估算,它的5个波段对太阳辐射的反演均有贡献;②用FY2C资料估算太阳辐射时,神经网络方法精度优于统计方法;③FY-2C估算太阳辐射的误差主要由卫星观测与地面观测的空间和时间范围的差异引起。  相似文献   

Experiences of modernity in the greenhouse: A cultural analysis of a physicist “trio” supporting the backlash against global warming     

Myanna Lahsen   《Global Environmental Change》2008,18(1):204-219

This paper identifies cultural and historical dimensions that structure US climate science politics. It explores why a key subset of scientists—the physicist founders and leaders of the influential George C. Marshall Institute—chose to lend their scientific authority to this movement which continues to powerfully shape US climate policy. The paper suggests that these physicists joined the environmental backlash to stem changing tides in science and society, and to defend their preferred understandings of science, modernity, and of themselves as a physicist elite—understandings challenged by on-going transformations encapsulated by the widespread concern about human-induced climate change.  相似文献   

Contrastive Study of the Circular Economy of Coal Resource City Based on Ecological Efficiency and C Model     

YU Huilu  DONG Suocheng  LI Yu  LI Zehong  LI Fei 《资源与生态学报(英文版)》2016,7(5):323-333

Being a developing country, the evaluation of Chinese circular economy should have its particular criterion that suits for specific national conditions. With the growth of economy, Chinese environmental loads should be permitted to increase at an appropriate speed. Based on this concept, this paper divides the process of evaluation into two parts which include evaluation of development level and evaluation of development performance. Firstly, this paper sets up a reference system which includes Zaozhuang City of Shandong Province, Jiaozuo City of Henan province, Shizuishan City of Ningxia Hui Autonomous Region and China that is regarded as a region respectively, analyzes the development level of circular economy of coal resource cities based on the evaluation indicator of ecological efficiency, and puts forward the future direction of circular economy of coal resource cities. Secondly, based on C Model of Circular Economy, this paper constructs the measurement model of development performance in which study regions are analyzed in a particular period that is from 2000 to 2020, and evaluates the development performance of circular economy for study regions according to the relationship of growth multiples between economic scale and environmental loads. We can draw several main conclusions: firstly, the development pathways of all four study regions belong to type Ⅱ which resource efficiency is preferred. Secondly, the comprehensive energy consumption efficiencies of coal resource cities were left far behind by China’s average level. Thirdly, the circular economies of all study regions have achieved remarkable progress. Fourthly, the development level of circular economy can be evaluated from two dimensions which consist of horizontal comparison method and vertical comparison method. Fifthly, C model is an appropriate development model that suits for Chinese national conditions and could be selected as an important method to evaluate regional development performance of circular economy.  相似文献   

东秦岭地区中生代金钼多金属矿C-H-O同位素组成研究          下载免费PDF全文

王涛  祝朝辉  刘淑霞  白俊豪  尉向东  李明立 《地质找矿论丛》2017,32(2):180-189

文章在系统收集近年来东秦岭地区主要的钼、金、铅锌银矿C-H-O同位素数据分析的基础上,对区内的C-H-O同位素组成进行了综合研究。其结果认为东秦岭钼金多金属矿床的成矿流体来源极为相似,初始成矿流体均为与岩浆活动有关的高温深源流体,随着岩浆活动和成矿作用的进行,大气降水与地壳岩石水岩反应作用后的浅源流体不断加入其中,使得矿床的成矿流体表现深源流体和具有雨水性质的浅部流体的混合特征;富含成矿物质的成矿流体聚集在地壳下部的拆离带,与下部地壳岩石相互作用,形成复杂的流体-岩浆混合体系,受构造运动控制,在不同的地球物理化学边界层沉淀成矿。  相似文献   

Facile Synthesis of Thiol‐functionalized Mesoporous Silica – Their Role for Heavy Metal Removal Efficiency          下载免费PDF全文

Ling‐Chu Lin  Munusamy Thirumavalavan  Jiunn‐Fwu Lee 《洁净——土壤、空气、水》2015,43(5):775-785

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青藏高原不同生境中祁连圆柏叶片δ13C变化及其与环境和树高的关系     

张有福  陈拓  张鹏  徐国保 《冰川冻土》2015,37(5):1388-1395

以分布于青藏高原东北缘的优势乔木祁连圆柏为研究对象,分析了叶片δ¹³C值变化及其与树高、土壤含水量、降雨量和叶片碳氮含量的关系.研究结果表明:研究区祁连圆柏叶片δ¹³C值的变化范围为-28.58‰~-23.95‰,平均值为-25.66‰,变化幅度为4.63‰,而同一生境不同个体之间的变化幅度为2.69‰和2.93‰,说明祁连圆柏叶片δ¹³C值的变化是植物自身遗传特性与环境因子共同作用的结果.叶片δ¹³C值与树高呈明显的负相关关系(p<0.01),并且这种关系不随采样位点的不同而改变;与叶片C和N含量不相关,而与土壤含水量和年平均降水量显著负相关(p<0.001).  相似文献   

Computing the Periods of Light Variation of Blazar Objects 3C279 and OJ 287 with Autoregressive Spectral Analysis Method     

Jie Tang  Xiao-juan Zhang  Qiao Pang  Hao-Jing Zhang  Yong-Gang Zheng  Xiong Zhang 《Chinese Astronomy and Astrophysics》2010

The light variability is one of the main characteristics of blazar objects. Because of the complexity of their light curves, the present periodicity analysis methods are not yet perfect. Based on the modern spectral estimate theory, this paper has described in details the principles of the maximum entropy spectral estimate and autoregressive (AR) spectral estimate, analyzed the effect of the order number selection on the resultant model. Applying these methods to the periodicity analysis of the quasar 3C 279 and BL Lac object OJ 287, their light periods are obtained to be 7.14 and 11.76 yr, respectively. As is verified by experiments, the AR spectral estimate has a high resolution and is a rather good periodicity analysis method. Finally, the items noteworthy for the application of these spectrum estimation methods to the periodicity analysis of the light variations of blazars are mentioned.  相似文献   

Stable isotope composition of modern bryozoan skeletal carbonate from the Otago Shelf,New Zealand     

Stephen F. Crowley  Paul D. Taylor 《新西兰海洋与淡水研究杂志》2013,47(2):331-351

The oxygen (δ¹⁸O) and carbon (δ¹³C) isotope ratios of 10 species of living Bryozoa collected from the Otago Shelf, New Zealand were analysed to assess the extent to which isotopic equilibrium (relative to inorganic equilibrium isotope fractionation) is attained during the precipitation of skeletal calcium carbonate. The data reveal that whereas eight species of Bryozoa synthesise skeletal carbonate in apparent oxygen isotope equilibrium with respect to environmental conditions, two species (Celleporina grandis and Hippomonavella flexuosa) yield δ¹⁸O_calcite values which indicate significant disequilibrium oxygen isotope fractionation during calcification. Sufficient data are available from one species (C. grandis) to demonstrate that disequilibrium is probably related to kinetic factors associated with diffusion‐controlled transport of HCO₃‐ to the site of calcite precipitation. Carbon isotope signatures indicate significant departures from inorganic isotope equilibrium in all but one bryozoan species (Hippomenella vellicata). Although greater uncertainties are associated with estimates of the isotopic composition of total dissolved inorganic carbon (δ¹³C_SDIC), the data suggest that two factors—kinetic fractionation and incorporation of respiratory CO₂—are important in controlling carbon isotope disequilibrium. Where bryozoan species exhibit evidence for disequilibrium in both oxygen and carbon isotope systems (C. grandis, H. flexuosa), it is likely that kinetic factors are primarily responsible for observed departures from carbon isotope equilibrium. In contrast, the probable explanation for those species which display evidence for carbon isotope disequilibrium only, is that skeletal carbonate is precipitated from a DIC pool modified by the incorporation of respiratory CO₂. Differences between the carbon isotope composition of skeletal elements from the same species and co‐existing species living in the same community suggests that significant variations may occur in the extent to which marine DIC and respiratory CO₂ are utilised during calcification. Additional studies of carbon pathways associated with calcification are required to assess the relative effects of kinetic, metabolic, and environmental factors on the carbon isotopic composition of bryozoan skeletal carbonate.  相似文献   

天津市城建服务热线查询GIS系统的设计与开发     

刘阳  王刚  周丽珠 《地理空间信息》2012,10(4):102-104

城建服务热线查询系统将不同的城建管理服务统一到一个热线语音平台,建成了涵盖天津市整个城市建设管理工作的服务热线。介绍了天津市城建服务热线查询GIS系统的数据组织结构,详细描述了系统的功能设计,分析了系统的技术特点。  相似文献   

一种人工神经网络云分类方法的改进与应用   总被引：2，自引：0，他引：2       下载免费PDF全文

张振华  苗春生  曾智华  师春香 《应用气象学报》2012,23(3):355-363

采用2005—2009年FY-2C静止气象卫星可见光和红外自旋扫描辐射计的红外1(IR1)、红外2(IR2) 和水汽 (WV) 亮温资料,选取2449个云分类样本。设计两层嵌套的前向传递后向反馈 (BP) 人工神经网络模型,第1层网络选取IR1,IR2,WV亮温及IR1与WV亮温差和IR2与WV亮温差5个特征量,第2层网络选取特征量IR1与IR2亮温差,两层网络都采用一层隐含层且带有附加动量法的简单网络,降低了网络的冗余度。误差分析表明:嵌套BP人工神经网络模型的分类准确率在中云和薄卷云这两类上分别提高了42.7%和11.3%,整个分类模型的平均平方误差和标准化平均平方误差分别降低了6.1%和44.7%,相关系数提高了3.4%。通过3个个例的对比分析发现,嵌套模型的分类结果比传统模型的分类结果更合理,特别是在中低云和薄卷云的云量和位置分辨能力上有了较大提高。  相似文献