20世纪地球科学的发展

20世纪地球科学经历了大陆漂移、海底扩张和岩石层板块大地构造的发展过程 ,通过研究的深化和认识的更新 ,使得许多孤立的地质现象进一步得到规律性的认识 .岩石层板块大地构造理论的基本内涵是活动论 ,查清地球的形成和演化历史 ,才能更深刻地认识它     

长江口及邻近海域现代沉积物中正构烷烃分子组合特征及其对有机碳运移分布的指示

报道了长江口及邻近海域现代沉积物中正构烷烃的浓度及分布特征,通过因子分析法对正构烷烃来源进行了探讨.结果表明,调查站位正构烷烃主要可归纳为3种类型:陆源输入优势型(单峰群)、陆源和海洋内生混合类型(双峰群)和石油类污染类型(单峰型,不具奇偶优势).长江口邻近站位正构烷烃色谱指标的突变,是长江河口区2种不同水团造成沉积物差异的客观反映.除P4外,研究站位总正构烷烃含量(∑n-Alk)与有机碳总量(TOC)相关性良好,且长江口东南-浙江沿岸软泥区正构烷烃的陆源高等植物组分(TER-Alk)、海洋内生组分(PL-1)、奇偶碳优势指数(CPI)等指标与运移距离呈线形关系.在因子分析显示不同来源的4种正购烷烃中,以陆源烷烃输入比重最大(51.5%),在陆源烷烃中又以东海河流物质贡献最大(49.1%);根据因子负荷差异,推测东海北部沉积有机质可能多数来源于苏北沿岸及老黄河口水下三角洲,冲绳海槽区则可能大部分来源于长江及东海内陆架物质,并探讨了其运移机理.     

国家防震减灾指挥中心的构成

介绍了防震减灾指挥中心作为领导和专家共同迅速有效处置地震应急事件的工作平台,该中心是国务院抗震救灾指挥的主要工作场所。防震减灾指挥中心包括指挥中心机房、指挥大厅和辅助工作区三部分。指挥中心建设是一项复杂的系统工程建设项目,包括了计算机系统、网络、通讯、声像、供电、空调、投影显示、GIS技术应用、数据库、软件开发、机房建设等。可对抗震救灾工作快速作出科学决策。     

基于点云的地铁隧道断面精确拟合与形变分析

针对三维激光扫描技术应用于地铁圆形、马蹄形等不同形状的隧道断面难以精确拟合和形变分析问题，提出了一种基于三次B样条曲线的隧道断面拟合分析方法，首先利用三次B样条曲线对断面进行拟合；然后根据拟合曲线提取断面特定点，实现断面形变分析。对某段地铁隧道点云数据进行断面分析表明，该方法可以快速准确地分析隧道断面的形变信息。     

BP-CCA方法用于中国冬季温度和降水的可预报性研究和降尺度季节预测

使用变形的典型相关分析(BP-CCA)方法,基于交叉检验的结果建立了东亚冬季500 hPa大尺度环流和中国冬季温度、降水的最优BP-CCA降尺度预测模型,并在此基础上进行了中国冬季温度和降水的可预报性研究,表明用东亚冬季500hPa高度场降维后的大尺度环流来解释中国冬季温度,平均距平相关系数(ACC)为0.7左右,最高可达0.9,解释中国冬季降水的平均ACC为0.3左右,最高可达0.7,温度的可预报性远高于降水,且二者的可预报水平存在明显的区域差异。可预报性研究表明东亚冬季500 hPa大尺度环流异常与中国冬季温度、降水异常有密切的联系,BP-CCA方法可以很好地揭示大尺度环流与温度、降水的内在联系,并且物理意义清晰。在东亚大尺度环流系统中,东亚大槽和西太平洋副热带高压是影响中国冬季温度、降水异常的重要系统。进一步利用国家气候中心海气耦合模式(CGCM/NCC)回报和预测的500 hPa环流场和BP-CCA方法对温度和降水进行降尺度预测应用,对温度和降水的预测效果明显高于模式直接输出的结果,而且对温度预测的改善高于对降水的改善。对模式预测的环流进行EOF(经验正交函数)分析,表明BP-CCA方法对降尺度要素预报的可预报性来源于CGCM/NCC对500 hPa高度场主要大尺度特征的模拟能力较好。     

Characterising and visualizing spatio-temporal patterns in hourly precipitation records

We develop new techniques to summarise and visualise spatial patterns of coincidence in weather events such as more or less heavy precipitation at a network of meteorological stations. The cosine similarity measure, which has a simple probabilistic interpretation for vectors of binary data, is generalised to characterise spatial dependencies of events that may reach different stations with a variable time lag. More specifically, we reduce such patterns into three parameters (dominant time lag, maximum cross-similarity, and window-maximum similarity) that can easily be computed for each pair of stations in a network. Furthermore, we visualise such three-parameter summaries by using colour-coded maps of dependencies to a given reference station and distance-decay plots for the entire network. Applications to hourly precipitation data from a network of 93 stations in Sweden illustrate how this method can be used to explore spatial patterns in the temporal synchrony of precipitation events.     

Greening in the circumpolar high-latitude may amplify warming in the growing season

We present a study that suggests greening in the circumpolar high-latitude regions amplifies surface warming in the growing season (May–September) under enhanced greenhouse conditions. The investigation used a series of climate simulations with the Community Atmospheric Model version 3—which incorporates a coupled, dynamic global vegetation model—with and without vegetation feedback, under both present and doubled CO₂ concentrations. Results indicate that climate warming and associated changes promote circumpolar greening with northward expansion and enhanced greenness of both the Arctic tundra and boreal forest regions. This leads to additional surface warming in the high-latitudes in the growing season, primarily through more absorption of incoming solar radiation. The resulting surface and tropospheric warming in the high-latitude and Arctic regions weakens prevailing tropospheric westerlies over 45–70N, leading to the formation of anticyclonic pressure anomalies in the Arctic regions. These pressure anomalies resemble the anomalous circulation pattern during the negative phase of winter Arctic Oscillation. It is suggested that these circulation anomalies reinforce the high-latitude and Arctic warming in the growing season.     

Association between winter temperature in China and upper air circulation over East Asia revealed by canonical correlation analysis

Canonical correlation analysis (CCA) was used to study the relationship between the winter temperature in China and the circulation at 500 hPa over East Asia. CCA identifies a number of paired patterns that depend on Principle Component (PC) truncation of the two fields. Retaining more PCs usually gives more physically meaningful CCA patterns, but the leading paired pattern has often less explained variance. When fewer PCs are adopted, the leading pattern possesses larger variance. However, it is often distorted in comparison with PC or rotated PC patterns. Various combinations with different PC and CCA patterns remained were tried, which shows that retaining as many PCs as possible and using the first several CCAs instead of only the first give most reasonable connection mechanisms. A statistical downscaling model based on CCA modes linking temperature with circulation was established to quantify the extent to which temperature variation can be explained by circulation. The model was optimised by varying numbers of the PCs and the CCA modes retained. With 13th PC truncation in the circulation and 8th PC truncation in the temperature as well as five CCA modes retained, the optimal CCA model is achieved based on cross-validation. The optimal downscaling model accounts for 47.5% temperature variance on average. However, there is a remarkable regional difference, which ranges from 10% to 70% in brier-based score (BBS). It is concluded that 500-hPa circulation is strongly linked to surface temperature in parts of the country, but it alone is not sufficient to achieve a successful statistical downscaling of the temperature for whole China.     

黄陇煤田转角勘查区煤的微观孔隙结构特征及其影响因素

煤的微观孔隙结构特征是煤储层特征的重要研究内容之一。选取黄陇侏罗纪煤田转角勘查区4个典型低阶煤样品为研究对象,以煤质特征研究为基础,进行压汞和液氮吸附实验,获取了不同测试方法的煤孔隙结构参数。根据两种测试方法的优缺点在孔径50nm处采用曲线拼接法进行联合,分析了全孔径段的比表面积和孔隙体积分布。结果显示:煤的比表面积主要分布在微孔、小孔和中孔三个区间,呈现“三峰”特征,表现为微孔>小孔>中孔>大孔的分布特征;孔隙体积主要分布在微孔、小孔和大孔。灰分含量和阶段孔径比表面积和孔隙体积具有较好的相关关系,但相关性强弱不同,总体显示和微孔、小孔及中孔呈正相关关系,而与大孔孔隙呈负相关关系,灰分含量与微孔、小孔的影响最大。显微组分中的镜质组和壳质组含量与大孔比表面积和孔隙体积呈正相关关系,与微孔、小孔呈负相关关系;惰质组含量与大孔孔隙比表面积和孔隙体积呈负相关关系,和微孔、小孔呈正相关关系。