松花江白山河段冰情数值计算及分析

根据水动力学、河流动力学、热力学、河冰水力学及固体力学等原理,针对松花江上游白山河段具体特征,建立了河冰数学模型,并应用有限差分计算方法,对白山河段冬季冰情演变进行了精确模拟。应用该河段1958-1973年共15年完整的地形、气象、水文、热力、冰情等原型观测资料,分别进行了模型参数率定及冰情数值模拟。研究结果表明:白山河段的封冻首先开始于白山坝址下游4 km的大崴子河段,然后封冻边缘逐渐上溯,最终到达松14断面;计算的白山河段冰花堆积体外形与河床纵剖面呈相似趋势;各种水力及冰情要素的数值计算结果和实测值吻合较好,所建立的数值模型能较好地模拟该河道的冰情。研究结果对东北地区河流冬季冰情研究及冰害防治具有一定的借鉴意义。     

基于势流理论和OpenFOAM的耦合模型对多向不规则波浪的模拟

基于势流理论的数值水池可以快速计算波浪的传播及其对建筑物的作用,但是势流理论是基于波浪的无黏性假设的,而在工程中,通常需要在固体边界及波浪破碎的区域考虑黏性效应。针对基于求解Navier-Stokes方程的黏性水池计算量较大、速度较慢的缺点,采用耦合的方法模拟多向不规则波浪的传播,即在外域通过基于势流理论的数值水池产生多向不规则波浪,内域采用求解Navier-Stokes方程和流体体积法(VOF方法)对自由表面进行追踪,通过外域所提供的边界波浪,内域计算可以在较小区域进行计算,从而达到减少计算量、提高计算效率的目的。     

A Survey of the Spatio-Temporal Data Model

Traditional GIS(Geographic Information System)mostly can only describe the transient state data and does not have the ability to deal with the temporal dynamic data. When the data changes, new data will take the place of the old data, namely the transient state change into another, and the old data will disappear. Therefore, it is unable to make an analysis of the updating changes of the data and predict the development trend of the future. In this case, TGIS (Temporal Geographic Information System) emerges and expands the time dimension on the basis of traditional GIS. Spatio-temporal data model is the key to TGIS. Spatio-temporal data modeling is not only related to dynamic expression of spatio-temporal objects, but also gives an important support for spatio-temporal analysis and reasoning. This paper summarized the theories and applications status at home and abroad of spatio-temporal data model in detail, illustrated family tree of spatio-temporal data model for the nearly fifty years, discussed improvement and application status of Base State with Amendments Model, Event-based Spatio-temporal Data Model, Object-oriented Data Model and other spatio-temporal data models, and raised the existing problems of spatio-temporal data model. The current existing problems mainly includes: ①There are a lot of spatio-temporal data models put forward, but some of them only focus on semantic design and neglect the verified; ②Most of existing spatio-temporal data model are for vector data, only the Event-based Spatio-temporal Data Model is raster data structure; ③At present, the expression the time-space information of geographic entity is relative separated with spatio-temporal data model; ④Spatio-temporal data model is mainly used in cadastral management, land use and forestry data updating, less application in other fields. In the end, the future development direction was put forward of spatio-temporal data model. In the time of big data and “Internet plus”, it is necessary to explore the big data spatio-temporal data model that supports multiple data formats.     

The North Atlantic Oscillation (NAO) and Europe Blocking and Their Impacts on Extreme Snowstorms: A Review

Large-scale, low frequency modes such as the North Atlantic Oscillation(NAO)and blocking, have an important modulation on the northern hemisphere weather and climate. In this paper, the physical mechanism studies on inter-decadal and decadal variability of NAO and blocking were summarized. The relationship between NAO regime transitions and the interannual variability of NAO in winter during was examined by using a statistical approach. The time-space relationship between NAO and European blocking were discussed. Based on two extreme cold and snowstorm events, the impacts on local weather especially the extreme events within the life cycle (two weeks) of the NAO and blocking were further examined. It was found that the frequently occurrence of the Eurasian extreme snowstorm was closely related to the special combination of NAO and blocking regime. In addition, the development of theoretical modes for NAO and blocking was discussed and issues that remain to be solved were proposed.     

Structuring velocity model of microseism based on genetic algorithm and Levenberg-Marquardt algorithm

为在射孔时间未知条件下达到微震速度模型矫正的目的,采用遗传算法交叉互换搜索最优初值和 Levenberg-Marquardt 算法局部锁定最优解的方式来构建微震速度模型。通过 6 层层状模型及井下不同数量检波器进行试算,随着检波器数量增加,构建的速度模型准确度越高,当检波器数量增加到 20 个时,误差约 13. 4 ×10 －3 ,目的层检波器数量越多,构建目的层速度误差越小,第 5 层检波器由 1 增加到 3 个时,精度提高 9. 1 ×10 －3 ,并且反演震源与实际震源距离相差 10 m,说明此方法在射孔时间未知条件下可以良好构建速度模型。     

三维高密度电阻率法在堤坝工程中的模拟试验

为检测堤坝中裂隙、洞穴及渗漏层等隐患的存在,利用三维高密度电阻率法对数字模型和物理模型建立的裂隙隐患进行探测,结果表明室内建立的物理模型在立体图和分层切片图中裂隙的形态有些变化,但其分布范围、位置与相对各自模型中实际的比例尺寸相差不大,说明数值模拟得出的结论可以为实际工程进行理论指导,具有一定的参考价值。     

安徽省地质灾害气象预报预警模型研究

通过对基于地质环境信息平台的地质灾害气象预报预警模型构建进行了探讨。拟在先期已具备的地质灾害预警分区、地质灾害易发分区基础上,以地质灾害"易发度"、预报降雨量、有效降雨量为因子,采用logistic回归模型确定各个评价单元的预警等级,经插值计算、图斑合并,实现地质灾害气象风险预警。     

钟姑地区典型矿床的重磁找矿模式

钟姑地区位于宁芜中生代火山岩盆地南段,已发现有白象山铁矿等多个大型铁矿,是长江中下游成矿带以玢岩型铁矿为主的矿集区。本文以钟姑地区实测岩石物性参数为桥梁,以实测重磁数据为基础,分析了该区白象山铁矿、钟九铁矿和云楼铁矿的重磁场分布特征,并根据典型矿区已知地质条件,运用成熟的2.5D重磁联合反演技术进行计算,从定量角度认识铁矿体深部发育形态、位置与重磁异常之间对应关系,建立钟姑地区白象山铁矿等典型矿床的重磁找矿模式,为该区进一步找矿突破提供地球物理场信息。     

GIS综合评价模型在地质灾害详细调查中的应用

以河南省登封市地质灾害调查为例,在分析地质环境条件的基础上,总结地质灾害发育特征,确定易发性分区评价指标,并运用GIS综合评价模型分析计算,得出的分区结果与实际吻合较好。通过对GIS综合评价模型的研究,可为大区域内地质灾害易发性评价提供参考。     

加权Logistic回归模型在火山岩型铜矿预测中的应用:以宁芜盆地中段为例

文中探讨了加权Logistic回归模型在宁芜盆地中段火山岩型铜矿预测中的应用。首先,结合研究区的成矿地质背景,提取地质体、构造、围岩蚀变三大类证据因子;其次,分析各证据因子与铜矿点之间的空间关系,认为姑山旋回、娘娘山旋回火山机构控制了本区火山岩型铜矿的空间分布,根据计算结果,选取与火山岩型铜矿密切相关的龙王山组、姑山组地层,姑山旋回粗面斑岩、娘娘山旋回二长斑岩、NW向构造1.5 km缓冲区、NE向构造1.3 km缓冲区、EW向构造4.5 km缓冲区、硅化、褐铁矿化、黄铜矿化等作为模型自变量;最后采用加权Logistic回归模型进行成矿概率计算,并结合成矿地质背景,圈定四个成矿远景区,分别为P1、P2、P3、P4,其中P1、P2、P3呈北东向展布,主要受娘娘山和姑山火山机构控制,P4为东西向分布,主要受龙王山火山机构控制,在这些预测区中,均存在已发现的铜矿体,说明预测可信度较高。