山西数字地下水位固体潮加卸载响应比与中强地震关系分析

运用加卸载响应比方法,计算和分析了山西省2008年以来数字化地下水位固体潮观测数据,并选取大于2倍加卸载响应比值作为异常判定指标,将山西及周边地区发生的ML≥4．0地震的参数与井水位固体潮响应比异常变化对比分析。结果表明,山西地区9口数字水位观测井的地下水位固体潮加卸载响应比异常变化与附近的地震活动存在不同程度的对应关系。从而说明,利用井水位固体潮观测的加卸载响应比是一种能有效识别和提取地震前兆的方法。     

缔合Legendre函数二阶导数的快速稳定递推算法

根据初等代数的基本原理,推导了一种缔合Legendre函数二阶导数的快速稳定递推算法。数值测试结果表明,在阶次高达3 600时,该方法与其他几种现有方法的计算精度相当,但计算效率比其他方法提高了一倍以上,并且该方法没有奇异性,适用于快速精确地计算任意纬度的缔合Legendre函数二阶导数值     

几种自由边界实施方法在完全 匹配层条件下的对比研究

传统的完全匹配层技术是一种能够较为有效地消除边界反射的边界条件,但是当表层为泊松比较高的自由表面时,该技术可能会产生不稳定的现象.针对传统的完全匹配层技术固有的不稳定和掠射情况下吸收效果不佳等缺陷,发展了多轴完全匹配层、卷积完全匹配层以及将两者结合的多轴卷积完全匹配层等3种边界条件.本文介绍了水平自由表面的不同处理方法以及传统、多轴、卷积和多轴卷积等4种完全匹配层条件的原理,通过二维半无限空间模型的交错网格有限差分正演模拟对比,分析了几种自由边界实施方法在这几种完全匹配层条件下的稳定性,并通过提取单道波形与解析解进行对比,定性分析了水平自由表面几种不同处理方法的准确性以及各自的适用条件. 结果表明,泊松比和水平自由表面实施方法对波场模拟效果及其稳定性有重要影响.     

地球系统多圈层构造观的基本内涵

地球系统多圈层构造观的基本点是,把地球作为一个活的天体放在宇宙系统之中,更多地考虑地球深部壳-幔-核之间的相互作用,考虑地外天体对地球运动的作用和影响。这一构造观认为:构造运动并不仅仅是岩石圈板块之间的相互作用,而是地球系统的全球动力作用过程;陆与洋是对立统一相互转化的,单纯的大陆增生说是不正确的;地幔对流说至今未被证实,陆块是活动的,但不能大规模漂移;大陆地壳不是单纯地侧向或垂向增生,而是多旋回构造-岩浆作用叠合的产物;地球的构造不是均变式向前发展,而是非均变、非线性、旋回式向前演化的;地球表层在不同地史阶段,均有其受相应深断裂体系控制的不同的构造格局,大西洋-印度洋-太平洋式大洋盆体制,只是在中生代晚期以来才出现的。      

NUIST-ESM模式及其参与CMIP6的方案

近几年来,南京信息工程大学（NUIST）地球系统模拟中心致力于地球系统模式研发。最新发展的第三版本南京信息工程大学地球系统模式（NUIST-ESM v3）在原有的基础上改进了边界层方案与对流参数化方案,调整了模式中云物理过程,改进了耦合物理过程和海冰反照率等过程。此版本作为参加第六次国际耦合模式比较计划（CMIP6）的模式之一,注册了气候诊断、评估和描述试验（DECK）和历史气候模拟试验（Historical）以及ScenarioMIP、DAMIP、GMMIP、DCPP、PMIP、VolMIP和GeoMIP等7个比较子计划试验。目前DECK和Historical试验都已经完成,正将数据提交到ESGF数据发布平台。CMIP6模式比较子计划也将陆续完成并将发布数据,以供国内外学者下载使用。     

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Green's function for three-dimensional elastic wave equation with a moving point source on the free surface with applications

High-speed train seismology has come into being recently. This new kind of seismology uses a high-speed train as a repeatable moving seismic source. Therefore, Green's function for a moving source is needed to make theoretical studies of the high-speed train seismology. Green's function for three-dimensional elastic wave equation with a moving point source on the free surface is derived. It involves a line integral of the Green's function for a fixed point source with different positions and corresponding time delays. We give a rigorous mathematical proof of this Green's function. According to the principle of linear superposition, we have also obtained the Green's function for a group of moving sources which can be regarded as a model of a traveling high-speed train. Based on a temporal convolution, an analytical formula for other moving sources is also given. In terms of a moving Gaussian source, we deal with the issue of numerical calculations of the analytical formula. Applications to modelling of a traveling high-speed train are presented. We have considered both the land case and the bridge case for a traveling high-speed train. The theoretical seismograms show different waveform features for these two cases.     

CostMAP: an open-source software package for developing cost surfaces using a multi-scale search kernel

ABSTRACT

Cost surfaces are a crucial aspect of route optimization and least cost path (LCP) calculations and are used in awide range of disciplines including computer science, landscape ecology, and energy-infrastructure modeling. Linear features present akey weakness to traditional routing calculations along cost surfaces because they cannot identify whether moving from acell to its adjacent neighbors constitutes crossing alinear barrier (increased cost) or following acorridor (reduced cost). Following and avoiding linear features can drastically change predicted routes. We introduce an approach to address this adjacency issue using asearch kernel that identifies these critical barriers and corridors. We have built this approach into anew Java-based open-source software package– CostMAP (cost surface multi-layer aggregation program)– which calculates cost surfaces and cost networks using the search kernel. CostMAP allows users to input multiple GIS data layers and to set weights and rules for developing aweighted-cost network. We compare CostMAP performance with traditional cost surface approaches and show significant performance gains– both following corridors and avoiding barriers– by modeling the movement of alarge terrestrial animal– the Baird’s Tapir (Tapirus bairdii)– in amovement ecology framework and by modeling pipeline routing for carbon capture and storage (CCS).     

On the causes of pressure oscillations in low‐permeable and low‐compressible porous media

Nonphysical pressure oscillations are observed in finite element calculations of Biot's poroelastic equations in low‐permeable media. These pressure oscillations may be understood as a failure of compatibility between the finite element spaces, rather than elastic locking. We present evidence to support this view by comparing and contrasting the pressure oscillations in low‐permeable porous media with those in low‐compressible porous media. As a consequence, it is possible to use established families of stable mixed elements as candidates for choosing finite element spaces for Biot's equations. Copyright © 2011 John Wiley & Sons, Ltd.     

20世纪50年代初地质机构变革的考证和思考

原中央地质调查所、中央研究院地质研究所和资源委员会矿产测勘处都曾为中国地质事业的发展作出过重要贡献。但是,在1949年以前总体地质人员少、部门分散。为解决解放初期矿产资源紧缺和地质人员短缺的矛盾,1950年8月经政务院批准成立了中国地质工作计划指导委员会,及其领导下的矿产地质勘探局、中国科学院地质研究所和古生物研究所,开始了地质界一元化的机构改革。1951年5月7日新成立的三个机构开始运行,在运行初期实行地质研究人员的双重身份制度,即在矿产地质勘探局为技正,在研究所为研究员。1952年6月初步确定了各单位内设机构和人员,同时各专业地质队陆续成立,开始了人员的再次分配。1952年8月地质部成立,矿产地质勘探局,逐步转变为地质部的不同部门,地质研究所和古生物研究所全面接受地质部的领导。原中央地质调查所在这次变革中人员被分散到新成立的三个部门和有关单位,原来的内设机构被彻底分解,事实上被撤销。原中央地质调查所在长期实践中形成了以调查为本、调查与研究紧密相结合的研究风格和特色,在解放初期,不论是矿产地质勘探局还是中科院地质研究所和古生物研究所都围绕国家急需的矿产资源开展工作,都谈不上与中央地质调查所的机构传承关系。