基于FY-3C微波辐射成像仪海表温度产品的偏差订正方法研究

提出一种针对FY-3C搭载的微波辐射成像仪(MWRI)海表温度产品的分段回归偏差订正方法,该方法通过引进气候态海表温度数据,建立与关联实测海表温度相匹配的回归模型,并通过对模型中关联变量的误差分析,选择最优样本进行分段回归,以实现对海表温度数据的重新估计。通过对MWRI海表温度数据的偏差订正试验表明,采用分段回归方法获得的订正结果无论在误差指标的空间分布还是时间序列上,都要明显优于采用传统概率密度函数偏差订正方法的结果。其中,采用概率密度函数方法订正后的海表温度产品误差标准差和均方根误差从订正前的0.9—1.0℃,减小到0.8℃左右,而采用分段回归方法获得相应的订正误差仅为0.6℃左右,订正效果有明显改善。     

城市轨道交通盾构隧道病害空间分布特征量化研究

随着地铁的不断建设与投入使用,我国正在逐步进入地铁运营养护期,地铁病害检测与运营养护也逐渐得到重视。随着地铁运营年限的增加,病害也呈现加重趋势。通过三维激光扫描技术获取隧道病害全面信息,利用空间自相关性分析地铁隧道病害的地理空间分布特征,对于认识病害形成机理,防治病害具有重要意义。本文以某地铁隧道通过三维激光扫描所获得的水平收敛数据为基础,利用空间自相关分析法定量分析了病害在地理空间上的分布特征,以及与周边水文地质环境的关系。结果表明,隧道病害在地理空间分布上呈现显著的空间正相关与空间集聚特性,且病害严重区与隧道周边水文地质环境密切相关。本文结果为隧道病害地理空间分布特征研究、认识病害分布规律及后期病害治理提供了有效依据。     

思茅坳陷油气地质特征与勘探前景

思茅坳陷存在古生界和中一新生界两套沉积盖层,具有多套生储盖组合。以二叠系、三叠系为主力烃源岩,储层低孔低渗,侏罗系一白垩系“红层”组成区域盖层。思茅坳陷气水同喷、原油显示表明,该区海相地层仍有油气勘探前景,以存在K3-N区域盖层、断裂改造较弱、源岩成熟度较低、构造发育的英德一景谷、勐腊一勐满含油气保存单元为首选靶区,具有一定勘探前景。     

长江口斜压诊断模式三维流场数值模拟

建立了σ坐标系下长江口斜压诊断模式三维流场数学模型,采用k-kl二方程紊流闭合模型求解垂向涡粘系数,计算域内恒定、非均匀盐度场反映了计算域密度斜压效应。验证结果表明,斜压诊断模式的模拟成果较切合实际。模型成功复演了长江口水域由往复流向旋转流过渡的流场特性;潮波从四条汊道传入后在分汊口附近相遇形成多个会潮点,其位置随着径流的大小、潮汐的强弱、汊道的形态等因素而变化。     

Water Self-Softening Processes at Waterfall Sites

Many rivers in tropical and subtropical karst regions are supersaturated with respect to CaCO3 and have high water hardness. After flowing through waterfall sites, river water is usually softened, accompanied by tufa formation, which is simply described as a result of water turbulence in fast-flowing water. In this paper, a series of laboratory experiments are designed to simulate the hydrological conditions at waterfall sites. The influences of air-water interface, water flow velocity, aeration and solid-water interface on water softening are compared and evaluated on a quantitative basis. The results show that the enhanced inorganic CO2 outgassing due to sudden hydrological changes occurring at waterfall sites is the principal cause of water softening at waterfall sites. Both air-water interface area and water flow velocity increase as a result of the "aeration effect", "low pressure effect" and "jet-flow effect" at waterfall sites, which greatly accelerates CO2 outgassing and therefore makes natural w     

结构扫描雷达对钢筋混凝土构件的三维切片成像

基于结构扫描雷达网格测线的数据采集方式,提出了一种用于钢筋混凝土构件的三维切片成像算法。先用克希霍夫偏移进行聚焦处理,使反射波自动归位到其真实空间位置;再进行三维插值,从少量的测量数据获得重建目标空间的足够信息;最后对两方向的数据信息融合,增强目标反应,减小噪声干扰,提高检测效率。对实验台和实际建筑的检测验证了该算法的有效性和可行性。结果表明,通过对结构扫描雷达数据的三维切片成像,能更加全面而细致地了解钢筋混凝土构件的内部准确信息,使用的算法能清晰分离出点目标和横、纵方向的线性目标,为雷达图谱的解释提供了可靠的方法和依据,对相关检测工程和质量鉴定具有重要意义。     

基于ANSYS与OpenGL的高速公路结构物仿真建模及三维地层地表修剪方法

现代三维视景建模与仿真技术在高速公路工程选线、施工以及运营管理中具有良好的应用前景。结构物的仿真建模以及能反映施工前后地表形态变化的三维地层模型研究是高速公路信息化中的重要问题。介绍了一种借用ANSYS有限元分析软件提取结构物三维模型表面几何信息的简便方法;结合OpenGL纹理贴图技术,实现了结构物的仿真建模;针对结构物施工后对地表形态改变较大的问题,提出利用结构物表面数据对三维地层模型地表网格进行修剪的方法--地表网格竖直投影修剪法。把上述方法应用到广东省某高速公路高边坡的三维视景仿真建模中,结果表明,边坡的仿真模型较逼真。三维地层模型修剪后的地表形态与真实情况接近,验证了方法的合理性、可靠性。     

火山岩覆盖区三维地震勘探方法探究

宣化——下花园煤田位于燕山山脉的西段,区内地形复杂,成孔形式不一,采集难度大;火山岩覆盖范围广,浅层地震地质条件较差,地震记录信噪比低,静校正问题突出。为了查清宣东矿井深部煤炭资源状况,除了克服地表影响因素外,还需攻克该区火山岩对地震信号的屏蔽难题。通过对岩石出露区及黄土覆盖区进行试验分析,采取了高叠加次数等措施,有效地压制了干扰,提高了信噪比,在此基础上对地震记录进行一些有针对性资料处理技术,如绿山静较正技术等,使目的层有效波反应明显。本次勘探圈定了上覆火成岩范围及火成岩破坏区,控制了区内主要可采煤层Ⅲ3、Ⅴ2煤层的埋藏深度及构造形态,解释断层20条及Ⅲ3煤层火成岩破坏区3处,勘探成果表明,本次勘探所采用的野外采集措施和资料处理方法是行之有效的。     

Geochemistry and Crustal Evolution of Volcano-sedimentary Successions and Orthogneisses in the São Gabriel Block, Southernmost Brazil — Relics of Neoproterozoic Magmatic Arcs

Precambrian metaplutonic rocks of the São Gabriel block in southernmost Brazil comprise juvenile Neoproterozoic calc-alkaline gneisses (Cambaí Complex). The connection with associated (ultra-)mafic metavolcanic and metasedimentary rocks (Palma Group) is not well established. The whole complex was deformed during the Brasiliano orogenic cycle. Both metasedimentary and metavolcanic rocks as well as metaplutonic rocks of the Cambaí Complex have been sampled for geochemical analyses in order to get constraints on the tectonic setting of these rocks and to establish a tectonic model for the São Gabriel block and its role during the assembly of West-Gondwana. The major element compositions of the igneous rocks (Palma Group and Cambaí Complex) indicate a subalkaline character; most orthogneisses have a calc-alkaline chemistry; many metavolcanic rocks of the Palma Group show signatures of low-K tholeiitic volcanic arc basalts. Trace element data, especially Ti, Zr, Y, Nb, of most igneous samples from both the lower Palma Group and the Cambaí Complex indicate origin at plate margins, i.e., in a subduction zone environment. This is corroborated by relative enrichment in LREE, low contents of Nb and other high field strength elements and enrichment in LILE like Rb, Ba, and Th. The data indicate the possible existence of two suites, an oceanic island arc and a continental arc or active continental margin. However, some ultramafic samples of the lower Palma Group in the western São Gabriel block indicate the existence of another volcanic suite with intra-plate character which possibly represents relics of oceanic island basalts (OIB). Trace element data indicate contributions from andesitic to mixed felsic and basic arc sources for the metasedimentary rocks. The patterns of chondrite- and N-MORB-normalized spider diagrams resemble the patterns of the igneous rocks, i.e., LILE and LREE enrichment and HFS depletion. The geochemical signatures of most igneous and metasedimentary samples and their low (⁸⁷Sr/⁸⁶Sr)_t ratios suggest only minor contribution of old continental crust.A geotectonic model for the São Gabriel block comprises east-ward subduction and following accretion of an intra-oceanic island arc to the eastern border of the Rio de la Plata Craton at ca. 880 Ma, and westward subduction beneath the newly formed active continental margin between ca. 750 and 700 Ma. The São Gabriel block represents relics of an early Brasiliano oceanic basin between the Rio de la Plata and Kalahari Cratons. This ocean to the east of the Rio de la Plata Craton might be traced to the north and could possibly be linked with Neoproterozoic juvenile oceanic crust in the western Brasília belt (Goiás magmatic arc).     

三维变分同化雷达资料暴雨个例试验

采用中国新一代数值预报模式及其同化系统开展雷达资料的三维变分同化和数值模拟研究.通过一次暴雨个例的对比试验,结果表明:不考虑垂直运动影响的情况下,仅同化多普勒雷达径向风资料可以增加初始场中的中小尺度系统信息,并在一定程度上改善预报开始阶段的降水;同化由反射率因子导出的垂直速度、雨水混合比并令上升区饱和,可以较大改善降水预报结果;联合同化径向速度和反射率因子资料将得到它们的共同影响.模拟的β中尺度对流系统6 h的演变过程与观测十分一致,基本消除了旋转加强现象.发展旺盛阶段的对流单体南北方向范围约50 km,最大上升速度位于500 hPa附近,超过3.0 m/s;雨水最大含量在400 hPa附近,超过5.0 g/kg;云水最大值位于600 hPa,约0.5 g/kg;造成的降水强度可达30 mm/h,具有明显的β中尺度系统的特征.初始场中水汽是否达到β中尺度降水维持所需条件是至关重要的,如果初始场中水汽条件较差,即使含有云水、雨水、垂直速度的信息,这些信息也会很快消亡,难以维持下去;此外,雷达资料的质量控制也是十分重要的.