中国早奥陶世岩相古地理

本文是中国早、中和晚寒武世岩相古地理诸文的继续[1-3]。在笔者等的华北地区、华南地区和西北地区寒武纪和奥陶纪定量岩相古地理研究及编图成果的基础上,结合其他地区的地质资料,编制出了中国早奥陶世早期和晚期岩相古地理图两幅,并撰写出本文。在华北地区,作图单位分早奥陶世早期和晚期,以冶里期和马家沟二期分别代表其早期和晚期。在华南地区,作图单位亦分早奥陶世早期和晚期,以新厂期和宁国期分别代表其早期和晚期。在西北地区和其他地区,作图单位均为早奥陶世,不分早期和晚期。华北地区、华南地区和西北地区研究程度较高,其岩相古地理图和相应的文字论述都是定量的和比较详细的。其他地区的研究程度较低,其岩相古地理图和文字论文都是定性的或概略性的。定量,即每个古地理单元的划分都有确切的定量资料和定量图件为依据。这种定量的岩相古地理图对石油、天然气以及其他矿产的预测和勘探最有用处。中国早奥陶世岩相古地理的基本格局仍和寒武纪各世的一样,是两槽和三台相间分布。两槽即天山北山蒙辽吉槽地和昆仑秦岭槽地,三台即准噶尔蒙兴台地、塔里木柴达木华北台地和西藏华南台地。这些古地理单元及其次级古地理单元的范围和特征,有些与晚寒武世或中及早寒武世的相同或基本上相同,有些则大不相同,这是由早奥陶世的大范围的海侵决定的。     

水资源(环境)承载力的研究进展

概述了水资源(环境)承载力的概念、特征、量化评价方法及其总体研究的进展。强调了系统研究水资源(环境)承载力的重要现实意义。指出了当前研究中的不足,以及有待进一步研究的问题。     

基于分布式水文模型的雅鲁藏布江径流水源组成解析

为开展河川径流的水源解析，构建过程描述和本构参数两方面均有较强物理性的分布式水文模型。以雅鲁藏布江为对象，利用水文分区曲线对降雨、融雪和融冰等不同水源主导的流量过程进行划分，以划分的流量过程线子集对相应水文过程参数进行分步率定，提高了水文模型参数的物理性，以此构建了雅鲁藏布江流域分布式水文模型及参数集，内部多个水文站点和流域雪水当量的验证表明模型具有良好的性能。基于模型解析了2001—2015年间雅鲁藏布江的径流水源组成，降雨、融雪、融冰水源对总径流量贡献的比例分别为66%、20%和14%。本文方法对高山寒区径流的水源解析有普遍意义，结果对理解气候变化下雅鲁藏布江径流变化趋势有参考价值。     

介形虫壳元素成分的初步测试

用能谱仪初步测试了46个介形虫样品的元素成分,结果表明现代介形虫壳的元素成分变化小,Ca为其主要成分(含Ca94.12—99.8％),Si、Al含量很低。新生代介形虫壳的成分和现代介形虫壳的成分相似.中生代和古生代的介形虫壳含Ca量减少,Si、Al含量增高,还含微量的K、Mn、Fe、S、Mg等元素.介形虫壳成分的变化,推测与地质时期中介形虫的埋藏条件和石化程度等有关.     

Probabilistic analysis of borehole closure for through-salt well design

Probability levels, in the form of marginal cumulative distribution functions, are determined for the time it takes salt to contact a casing, which penetrates a salt canopy, and the time it takes the casing to yield once salt has contacted the casing, in support of through-salt well design activities required for deep-water, sub-salt environments. The finite-element method coupled with an advanced reliability method is used to perform the analyses. Randomness caused by uncertainties in salt properties, lithostatic stress, drilling-mud pressure, production temperature, and borehole ellipticity is handled by including statistics and probability distributions for each of these random variables. The advanced reliability method takes full account of the random variables and processes without Monte Carlo simulation, by using a method for assessing reliability statistics that computes response probabilities in a direct and efficient manner. This advanced reliability method falls under the general category of fast probability integration schemes.     

Stochastic simulations of ocean waves: An uncertainty quantification study

The primary objective of this study is to introduce a stochastic framework based on generalized polynomial chaos (gPC) for uncertainty quantification in numerical ocean wave simulations. The techniques we present can be easily extended to other numerical ocean simulation applications. We perform stochastic simulations using a relatively new numerical method to simulate the HISWA (Hindcasting Shallow Water Waves) laboratory experiment for directional near-shore wave propagation and induced currents in a shallow-water wave basin. We solve the phased-averaged equation with hybrid discretization based on discontinuous Galerkin projections, spectral elements, and Fourier expansions. We first validate the deterministic solver by comparing our simulation results against the HISWA experimental data as well as against the numerical model SWAN (Simulating Waves Nearshore). We then perform sensitivity analysis to assess the effects of the parametrized source terms, current field, and boundary conditions. We employ an efficient sparse-grid stochastic collocation method that can treat many uncertain parameters simultaneously. We find that the depth-induced wave-breaking coefficient is the most important parameter compared to other tunable parameters in the source terms. The current field is modeled as random process with large variation but it does not seem to have a significant effect. Uncertainty in the source terms does not influence significantly the region before the submerged breaker whereas uncertainty in the incoming boundary conditions does. Considering simultaneously the uncertainties from the source terms and boundary conditions, we obtain numerical error bars that contain almost all experimental data, hence identifying the proper range of parameters in the action balance equation.     

STUDY OF INFILTRATION INTO A HETEROGENEOUS SOIL USING MAGNETIC RESONANCE IMAGING

In this paper, the feasibility of using magnetic resonance imaging (MRI) to study water infiltration into a heterogeneous soil is examined, together with its difficulties and limitations. MRI studies of ponded water infiltration into an undisturbed soil core show that the combination of one- and two-dimensional imaging techniques provides a visual and non-destructive means of monitoring the temporal changes of soil water content and the moisture profile, and the movement of the wetting front. Two-dimensional images show air entrapment in repetitive ponded infiltration experiments. During the early stages of infiltration, one-dimensional images of soil moisture profiles clearly indicate preferential flow phenomena. The observed advance of wetting fronts can be described by a linear relationship between the square root of infiltration time (√t) and the distance of the wetting front from the soil surface. Similarly, the cumulative infiltration is also directly proportional to √t. Furthermore, from the MRI infiltration moisture profiles, it is possible to estimate the parameters that feature in infiltration equations. © 1997 by John Wiley & Sons, Ltd.     

孟加拉湾中部表层沉积物常微量元素地球化学:物源指示意义

通过对取自孟加拉湾中部的110个表层沉积物样品进行了常微量元素测试分析,探讨了其物质来源。在所有测试元素中,Si含量最高,其次为Al,且这两种元素的分布特征基本一致。化学蚀变指数（CIA^*）平均值为72.07,指示研究区沉积物风化程度位于喜马拉雅源区和印度源区沉积物之间。因子分析和判别函数计算分析表明研究区沉积物主要来自喜马拉雅源区和印度源区。使用Ti标准化后的元素比值反演模型估算的喜马拉雅源区和印度源区对研究区沉积物的相对贡献比例分别为83.5%和16.5%。其中,喜马拉雅源区对研究区东部沉积物贡献相对较大,而在研究区西部印度源区贡献比例相对东部为高。喜马拉雅源区物质向研究区输运的主要动力机制包括浊流及其溢流、表层季风环流携带的河流冲淡水,而印度源区物质主要通过表层季风环流特别是东印度沿岸流向研究区输运     

淡水浮游植物计数与定量方法

显微镜计数法是淡水浮游植物计数最常用的经典方法,是浮游植物生物量测定的基本方法,也是衡量其他测定方法准确性的依据.随着科技的发展,可见分光光度法、荧光分光光度法、流式细胞显微镜计数法、库尔特计数法等新型细胞计数法相继问世.对各种方法的特点进行比较,结果表明:光密度法、流式摄像机计数法、流式细胞仪法、叶绿素a法等仅能够分析测定浮游植物生物量,而显微镜法是测量浮游植物粒径的经典方法,不仅可以测定浮游植物生物量,还可以进行浮游植物的种类及群落结构分析.以上这些方法都可以用于浮游植物的计数与定量,可以根据不同的需求来选择最佳的浮游植物计数方法,如分析方便性、样本处理速率、样本大小等.但显微镜计数法在淡水生态学中具有不可替代的作用.     

基于水化学和同位素评价马莲河下游地下水补给河水的时空变化

准确评价地下水对河水的补给量是流域水资源量管理和合理利用的基础。在马莲河流域下游采集不同季节地表水和地下水样品75组,利用Cl^-、电导率（EC）和D、¹⁸O同位素多方法联合评价,识别了地下水补给河水的位置、补给量及其季节变化。结果表明：马莲河水EC和Cl^-质量浓度沿着流向均呈降低趋势,δD和δ¹⁸O值沿流向减小。雨季EC和Cl^-质量浓度最低,δD和δ¹⁸O值最高。地下水各组分浓度均低于河水,时空变化不明显。地下水单宽排泄量存在时空变异,上段和下段为地下水强排泄区,中段地下水排泄较弱,不同季节地下水排泄量占总排泄量的72.20%～95.07%。雨季地下水单宽排泄量显著降低,河水中基流比例由雨季前期的68.89%降至29.43%。整体上,地下水补给河水季节变化明显,而空间变化规律较为稳定。研究成果有利于深入认识河水和地下水的相互作用机制,并为当地水资源利用提供基础依据。