Long-Term Trend of Temperature Derived by Statistical Downscaling Based on EOF Analysis   总被引：1，自引：0，他引：1       下载免费PDF全文

FAN Lijun  FU Congbin  CHEN Deliang 《Acta Meteorologica Sinica》2011,25(3):327-339

This study analyzes the ability of statistical downscaling models in simulating the long-term trend of temperature and associated causes at 48 stations in northern China in January and July 1961–2006. The statistical downscaling models are established through multiple stepwise regressions of predictor principal components (PCs). The predictors in this study include temperature at 850 hPa (T850), and the combination of geopotential height and temperature at 850 hPa (H850+T850). For the combined predictors, Empirical Orthogonal Function (EOF) analysis of the two combined fields is conducted. The modeling results from HadCM3 and ECHAM5 under 20C3M and SERS A1B scenarios are applied to the statistical downscaling models to construct local present and future climate change scenarios for each station, during which the projected EOF analysis and the common EOF analysis are utilized to derive EOFs and PCs from the two general circulation models (GCMs). The results show that (1) the trend of temperature in July is associated with the first EOF pattern of the two combined fields, not with the EOF pattern of the regional warming; (2) although HadCM3 and ECHAM5 have simulated a false long-term trend of temperature, the statistical downscaling method is able to well reproduce a correct long-term trend of temperature in northern China due to the successful simulation of the trend of main PCs of the GCM predictors; (3) when the two-field combination and the projected EOF analysis are used, temperature change scenarios have a similar seasonal variation to the observed one; and (4) compared with the results of the common EOF analysis, those of the projected EOF analysis have been much more strongly determined by the observed large-scale atmospheric circulation patterns.  相似文献   

零偏移距共反射面叠加原理及其在工程地震勘探中的应用     

刘国华  李庆春  唐小平  肖梅 《西安地质学院学报》2011,(1):101-104

对一种能增强工程地震勘探数据质量的新叠加技术——零偏移距共反射面叠加进行了研究。目前模拟零偏移距剖面常规方法存在需要精确宏速度模型及不能对地下反射界面产生最佳照明的问题,而零偏移距共反射面叠加具有完全数据驱动、与宏速度模型无关、能够产生对地下反射界面最佳照明及提高模拟零偏移距剖面成像质量的优势。针对零偏移距共反射面叠加还未在国内工程地震勘探中进行广泛应用的现状,详细介绍了零偏移距共反射面叠加基本原理及其实现过程,并使用一套人工合成断层模型数据及来自某高速公路段附近一条二维测线的实际工程地震勘探数据进行了测试计算。理论模型试算结果及在工程地震勘探实际资料处理中的应用表明零偏移距共反射面叠加可提高地震数据信噪比,增强地震反射同相轴连续性,改善模拟零偏移距剖面质量,是一种非常有发展前景的工程地震成像方法。  相似文献   

施工期岩锚梁岩台破坏模式及稳定性分析     

董家兴  徐光黎  申艳军  朱可俊 《地质科技情报》2011,30(6):133-137

针对西南某大型水电站地下厂房岩锚梁岩台区节理发育的特点,并考虑辉绿岩脉等软弱带的影响因素,结合现场调查,利用关键块体理论方法分析得出开挖过程中岩台主要破坏模式为滑动、滑移—拉裂、弯曲—拉裂以及辉绿岩脉松动溃散4种,其中,上、下直墙的陡倾角结构面组合特征及辉绿岩脉的发育直接影响岩台的成型与稳定,开挖过程中针对各发育特征采...  相似文献   

中国耕地保护机制建设研究进展   总被引：4，自引：0，他引：4  

李广东  邱道持  王平 《地理科学进展》2011,30(3):282-289

本文综合运用文献资料法、对比分析法评述了中国耕地保护机制建设研究进展,分析了存在的主要问题,并展望了下一步的研究重点与方向。研究结果表明:中国耕地保护机制建设重点研究了耕地保护经济补偿机制和共同责任机制。对经济补偿模式与整体框架设计、经济补偿标准厘定、经济补偿资金管理与运作、中央政府-地方政府耕地保护关系、耕地保护多主体共同责任关系等问题进行了分析。基于分析得出机制建设是耕地保护的治本之策,农户行为与意愿研究、耕地非市场价值研究、中央政府激励机制设计将是下一步研究主要方向的结论。  相似文献   

阳储岭成矿岩体的地球化学特征   总被引：5，自引：0，他引：5  

莫名波 《矿物岩石》1990,10(2):82-91

本文从常量元素、微量元素、稀土元素以及稳定同位素等方面,研究并论述阳储岭斑岩钨(钼)矿田成矿岩体为铝过饱和、弱酸性、属查氏化学分类二类4—5科、钙碱性岩类,具有轻稀土富集、没有Eu和以Ce的亏损富集,以及小的正δ~(34)s、中等偏大的δ~(18)O_(全岩)值、幔源锶与壳源锶相近的稳定同位素地球化学特征,与斑岩铜矿岩体的地化特征具有诸多相似之处,为矿田成矿岩体成因研究以及论述矿床主要形成白钨矿的地化条件方面,提供了较好的资料.  相似文献   

Study of melt and a clast of 546 Ma magmatic arc rocks in the 65 Ma Chicxulub bolide breccia,northern Maya block,Mexico: western limit of Ediacaran arc peripheral to northern Gondwana     

《International Geology Review》2012,54(10):1180-1193

The basement of the Maya block of eastern Mexico is generally covered by Mesozoic and Cenozoic platformal carbonate rocks. However, the 65.5 Ma Chicxulub meteorite impact in the northern Yucatan Peninsula excavated deep into the crust and brought crystalline basement fragments into the impact breccias. Common Pb isotopic data from impact melt and a granitic clast from drill core (Y6) are highly radiogenic, consistent with the Archaean derivation. A granodiorite clast in this breccia from drill core (Yaxcopoil-1) yielded a continuous range of concordant ²⁰⁶Pb/²³⁸U laser ablation inductively coupled plasma mass spectrometry zircon ages between 546 ± 5 Ma and 465 Ma, with three discordant zircons having ²⁰⁶Pb/²³⁸U ages between 130 Ma and 345 Ma. The ca. 546 Ma age is interpreted as the age of granodiorite intrusion, with younger ages representing variable Pb loss during melting associated with the meteorite impact. This is consistent with previous U–Pb zircon data that gave an upper intercept age of 550 ± 15 Ma at Chicxulub, which becomes 545 ± 5 Ma when combined with the zircon data from distal ejecta. Such arc rocks are absent in the southern Maya block, and in the neighbouring Oaxaquia terrane (s.s.) they are replaced by a 546 ± 5 Ma plume-related dike swarm. On the other hand, Ediacaran arc rocks continue through the peri-Gondwanan terranes of the Appalachians and Europe (Florida, Carolinia, Avalonia, Iberia, Armorica, Massif Central, Bohemia, and NW Africa). Arc magmatism in these areas ended between 570 Ma (Newfoundland) and 540 Ma (Carolinia/UK) as the subduction zone was replaced by a transform fault along the northern Gondwanan margin. This age range is synchronous with the two-stage birth of Iapetus, suggesting that both are related to major plate reorganization. The source of plume-related dikes may have been located at the rift–rift–transform triple junction between Laurentia, Baltica, and Gondwana.  相似文献   

VizualAge: A Novel Approach to Laser Ablation ICP‐MS U‐Pb Geochronology Data Reduction     

Joseph A. Petrus  Balz S. Kamber 《Geostandards and Geoanalytical Research》2012,36(3):247-270

VizualAge, a new computer software tool for analysing U‐Pb data obtained by laser ablation‐inductively coupled plasma‐mass spectrometry, was developed. It consists of a data reduction scheme (DRS) for Iolite (a general mass spectrometry data analysis tool) as well as visualisation routines. In addition to the U/Pb and Th/Pb ages calculated by Iolite’s U‐Pb geochronology DRS, VizualAge also calculates ²⁰⁷Pb/²⁰⁶Pb ages and common Pb corrections for each time‐slice of raw data. Importantly, VizualAge allows one to display a live concordia diagram for visualising data on such a diagram as an integration interval is being adjusted. This provides instantaneous feedback regarding discordance, uncertainty, error correlation and common Pb. Several zircon data sets were used to illustrate how the live concordia could be used as a powerful inspection tool, revealing a single analysis to consist of zones of concordance, metamict areas, as well as inherited cores or younger overgrowths. VizualAge also constructs histograms, conventional and Tera‐Wasserburg type concordia diagrams, as well as 3D U‐Th‐Pb and total U‐Pb concordia diagrams. The precision and accuracy of data reduced with VizualAge are demonstrated with examples of the Ple?ovice, Temora‐2 and Penglai zircon reference materials. Data for zircon from the Long Lake Batholith (Wyoming craton) were used to illustrate how VizualAge calculated common Pb corrections and helped to expose as yet unexplained difficulties with accurately determining ²⁰⁴Pb.  相似文献   

“数字丽水”地理空间框架建设主要成果与技术创新     

钟春惺;江丽钧;朱建丰;林茂 《东北测绘》2013,(2):85-87

"数字丽水"地理空间框架建设项目建立了完善的地理实体数据库、地理信息公共平台以及一系列应用示范系统,目前已为政务部门20多家用户单位提供地理空间数据服务。本文对"数字丽水"地理空间框架项目建设的主要成果与技术创新进行总结。  相似文献   

沈阳地铁精密导线控制网成果分析     

蔺极平 《测绘与空间地理信息》2013,36(7):171-173

针对沈阳市地铁新、旧线路横跨两个坐标系统问题,笔者对同一套边长观测数据分别进行北京54、西安80两套坐标系统边长改化、平差,均取得良好成果,使地铁新旧控制成果可在54、80系统间随意比对,为地铁的旧点校正、安全贯通奠定了基础。  相似文献   

Shortest link method for contact detection in discrete element method     

Erfan G. Nezami  Youssef M. A. Hashash  Dawei Zhao  Jamshid Ghaboussi 《国际地质力学数值与分析法杂志》2006,30(8):783-801

With the increasing demand for discrete element simulations with larger number of particles and more realistic particle geometries, the need for efficient contact detection algorithms is more evident. To date, the class of common plane (CP) methods is among the most effective and widely used contact detection algorithms in discrete element simulations of polygonal and polyhedral particles. This paper introduces a new approach to obtain the CP by employing a newly introduced concept of ‘shortest link’. Among all the possible line segments that connect any point on the surface of particle A to any point on the surface of particle B, the one with the shortest length defines the shortest link between the two particles. The perpendicular bisector plane of the shortest link fulfils all the conditions of a CP, suggesting that CP can be obtained by seeking the shortest link. A new algorithm, called shortest link method (SLM), is proposed to obtain the shortest link and subsequently the CP between any two polyhedral particles. Comparison of the analysis time between SLM and previously introduced algorithms demonstrate that SLM results in a substantial speed up for polyhedral particles contact detection. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献