Analytical analysis of hydraulic effect of vegetation on shallow slope stability with different root architectures

A parametric study is performed to investigate hydraulic effect of vegetation on shallow slope stability with different root architectures in an infinite slope. Calculated results show during the first one hour of rainfall (181 mm/day), the exponential root architecture has higher ability to maintain shallow slope stability than the parabolic one. Under light rainfall (i.e., 20 mm/day) for 24 h, hydraulic effect of vegetation is more important inside root zone than outside root zone, while it is the opposite for rainfall intensities of 181 and 394 mm/day over the same duration. Parabolic rooted slope is more sensitive to rainfall pattern than bare one.     

湖南省气象局远程高性能计算环境的设计与实现

湖南省气象局依托国家超级计算长沙中心,建立了我省第一个远程高性能计算终端用户.针对远程环境的搭建,首先分析了湖南省气象局在高性能计算方面的需求,然后从省级气象部门业务计算需求出发,重点阐述了以高性能计算机集群"天河一号"为计算资源的远程计算环境的系统架构以及主要技术路线与方法.考虑到远程高性能强大的计算能力和省级气象部门作业提交的复杂需求,又进一步设计了湖南省远程高性能任务调度的系统流程以及保障远程计算环境高速稳定的多层面方案.最后也给出了高分辨率中小尺度WRF模式在该环境下运行的实际情况,计算速度改善非常明显.     

A hybrid parallel cellular automata model for urban growth simulation over GPU/CPU heterogeneous architectures

As an important spatiotemporal simulation approach and an effective tool for developing and examining spatial optimization strategies (e.g., land allocation and planning), geospatial cellular automata (CA) models often require multiple data layers and consist of complicated algorithms in order to deal with the complex dynamic processes of interest and the intricate relationships and interactions between the processes and their driving factors. Also, massive amount of data may be used in CA simulations as high-resolution geospatial and non-spatial data are widely available. Thus, geospatial CA models can be both computationally intensive and data intensive, demanding extensive length of computing time and vast memory space. Based on a hybrid parallelism that combines processes with discrete memory and threads with global memory, we developed a parallel geospatial CA model for urban growth simulation over the heterogeneous computer architecture composed of multiple central processing units (CPUs) and graphics processing units (GPUs). Experiments with the datasets of California showed that the overall computing time for a 50-year simulation dropped from 13,647 seconds on a single CPU to 32 seconds using 64 GPU/CPU nodes. We conclude that the hybrid parallelism of geospatial CA over the emerging heterogeneous computer architectures provides scalable solutions to enabling complex simulations and optimizations with massive amount of data that were previously infeasible, sometimes impossible, using individual computing approaches.     

基于ArcSDE文件地理数据库存储和设计的应用研究

主要介绍了Arc SDE数据引擎的原理,并对文件地理数据库管理存储模式进行分析和应用,采用分布式体系结构和计算机模式在五万动态更新项目中测试应用。充分利用资源将复杂的操作处理交由服务器执行,而对于简单的操作则由客户端直接完成。通过不断改进将这种数据生产的模式应用到各个测绘生产项目中。     

基于移动GIS的地理国情普查成果应用平台设计研究

为全方位地展示第一次全国地理国情普查成果,有效提高普查成果对政府、企业和公众的服务能力,以智能手机或平板电脑为终端,将无线互联网、卫星定位GPS与GIS等技术相结合,建立了基于移动GIS的地理国情普查成果应用平台,并详细介绍了平台的架构设计、功能设计和关键技术,为地理国情普查成果的应用拓展了思路。     

A model of submarine channel-levee evolution based on channel trajectories: Implications for stratigraphic architecture

Channel-levee systems are frequently interpreted as having a long history of cut-and-fill by channel-shaped features of different scales. Results from a simple geometric model based on a centerline migration algorithm combined with a vertical channel trajectory show that an incising-to-aggrading trajectory of a single channel can produce realistic morphologies similar to systems observed on the seafloor and subsurface, including features such as a basal erosional surface, coeval inner and outer levees, internal erosional boundaries, and terraces draped by inner levee deposits. Channel migration results in composite erosional surfaces that are distinct from topographic surfaces, and their formation does not require larger than usual erosional flows. Many submarine channels interpreted as underfit were probably carved by flows similar to the ones that eroded and deposited the entire channel system. We suggest that the features of most submarine channel-levee systems do not require large temporal variations in flow magnitude but can be explained by a simpler model whereby incision, migration and aggradation of a single channel form over time results in an apparently complex system.     

Structural architecture and a new tectonic perspective of Ovda Regio, Venus

The structural architecture of the Ovda Regio, Venus, derived from regional and detailed structural mapping of several key segments, reveals a new tectonic perspective, for the first time that varies from most of the existing tectonic models. The interpreted structural features include folds of different styles and scales, mega shear zones, ribbon structures, and other kinematic indicators. While concentric folding is predominant in the western Ovda, the eastern Ovda is characterized by shear folding. Two mega shear zones are recognised: dextral NW-SE trending GMSZ and a complimentary sinistral NE-SW trending KKSZ. Two tectonic stages are identified in a coherent and continuous strain history involving initial N-S compression that gave rise to regional east-west folding providing the fundamental tectonic architecture of a mountain fold-thrust belt. Ribbon structures in a broad radial pattern were developed contemporaneously with this folding. The second tectonic stage saw the development of a conjugate pair of mega shear zones and a range of kinematic indicators, consistent with continued N-S compression and the pre-existing fold pattern was modified resulting in the development of new fold structures, particularly in the eastern Ovda. The structural characteristics of Ovda Regio are analogous to those of Himalaya-Tibet collision front and also the Precambrian mobile belts of southern India.     

断层相的概念及应用

断层相是相分析方法在断层研究中的应用,它实现了对断层三维空间结构、断层结构单元及断层内部岩石物性特点的精确描述.从空间展布上来看,断层具有明显的带状结构,可以将其划分为破碎带和诱导裂缝带2部分.结构单元是断层空间的基本组成,也是断层相研究的基本对象.通过应用断层相分析手段对典型断层包络体内部变形特点进行精确描述,介绍了断层相在实际工作中的研究方法,并最终建立了硅质碎屑岩地层中拉张性断层相模式.分析表明,断层相分析方法对于研究断层的封闭性和稳定性具有非常重要的理论意义,在油气勘探开发及工程建设过程具有广泛的应用价值.     

鄂尔多斯盆地东缘上三叠统延长组砂体结构与层序地层学研究

运用层序地层学原理,对鄂尔多斯盆地东缘上三叠统延长组长7—长4+5曲流河三角洲露头进行深入的研究,划分出低位体系域、湖侵体系域和高位体系域,其内部砂体骨架是由席状化水下分流河道、曲流型分流河道、辫状型分流河道沉积构成。阐述了鄂尔多斯盆地东缘上三叠统延长组层序格架和砂体结构特征,建立了鄂尔多斯盆地层序地层格架内砂体分布模式,构建了层序地层格架内砂体结构与相对湖平面响应模式图。研究表明随湖平面变化层序格架内砂体结构发生规律性变化,低位体系域早期侵蚀,晚期充填呈复合状砂体;湖侵体系域砂体呈孤立状;高位体系域早期砂体发育不全,晚期呈席状砂体。     

建筑基坑检测的常见问题及对策

以某建筑基坑为例,探讨了不同观测时间对沉降的影响、不同位置观测点的沉降变化规律、地下水位升降对沉降的影响以及采取的对策。