东亚夏季风雨带和西太平洋副高季节变化的耦合特征

利用NCEP／NCAR数据集中1950～1999年4～9月500hPa位势高度和逐日降水率(PRATE)资料，通过奇异值分解，主要探讨了东亚夏季风雨带与西太平洋副高季节移动的耦合关系。分析发现，模态方差的大小只反映模态对整个分析时段和整个分析区域贡献的大小，但对某些时段、某些区域来说，方差较小模态的贡献很大；因而仅以模态方差贡献的大小来判定模态的重要性是不完全的，只有多个模态的配合才能比较全面地揭示两个场的耦合特征。结果表明：东亚夏季风雨带在不同地区的跳跃对应着西太平洋副高的三次突变，不同模态对三次突变有不同的贡献。     

APPLICATION OF UAVLS TO RAPID GEOLOGICAL SURVEYS

Three-dimensional scanning with LiDAR has been widely used in geological surveys. The LiDAR with high accuracy is promoting geoscience quantification. And it will be much more convenient, efficient and useful when combining it with the Unmanned Aerial Vehicle (UAV). This study focuses on UAV-based Laser Scanning (UAVLS)geological field mapping, taking two examples to present advantages of the UAVLS in contrast with other mapping methods. For its usage in active fault mapping, we scanned the Nanpo village site on the Zhangxian segment of the West Qinling north-edge fault. It effectively removed the effects of buildings and vegetation, and uncovered the fault trace. We measured vertical offset of 1.3m on the terrace T₁ at the Zhang river. Moreover, we also scanned landslide features at the geological hazard observatory of Lanzhou University in the loess area. The scanning data can help understand how micro-topography affects activation of loess landslides. The UAVLS is time saving in the field, only spending about half an hour to scan each site. The amount of average points per meter is about 600, which can offer topography data with resolution of centimeter. The results of this study show that the UAVLS is expected to become a common, efficient and economic mapping tool.     

上地幔超高压流体的金刚石压砧实验研究

地球深部流体主要是NaCl-H2O溶液,越到地球深部,它赋存的温度、压力越高,性质状态也不断变化,反之,亦然。当NaCl-H2O流体进入和脱离(上升过程)超临界状态时,其性质会发生截然不同的变化,影响着各种地质过程。使用金刚石压砧在高温高压下原位观测流体的实验,用谱学方法,结合同步辐射光源技术,成为定量化研究地球深部高温超高压流体的有效方法。作者使用同步辐射光源的红外谱研究了10GPa下的NaCl-H2O溶液;在地球化学动力学实验室研究了3GPa,650℃下的NaCl-H2O溶液红外谱,此测量方法可以提供温度压力和体积等数据,能研究其状态。NaCl-H2O溶液红外谱表明水分子主要振动谱受压力和温度影响是不同的。压力增加促使水分子主要振动谱向低波数变化。但是温度增加的效应相反。常温高压下水被压缩,结晶向紧密堆积变化。高温高压下的水有气、液、固和超临界流体各相。水分子间的氢键在近临界态开始减弱,氢键网络被破坏。     

后处理DGPS在海域调查中的研究与实践

通过分析后处理差分全球定位系统（differential global positioning system,DGPS）测量原理和其在海域调查中应用的具体事例,说明DGPS不仅使用方便、定位精度高,而且价格低廉,对其在海洋测绘领域的应用很有必要。     

准噶尔盆地吉木萨尔凹陷二叠系芦草沟组储层介—宏孔孔隙结构特征及控制因素

吉木萨尔芦草沟组页岩油资源潜力巨大,为探究其储层介—宏孔孔隙结构特征及控制因素,以研究区芦草沟组钻井岩心为对象,利用X射线衍射、铸体薄片、扫描电镜、孔渗测试、高压压汞、氮气吸附、分形理论、相关性分析等方法,对其储层特征、孔隙结构及控制因素进行了讨论。研究发现：1）研究区芦草沟组储层是一套以长英质碳酸盐岩（A岩）、长英质黏土岩（B岩）、灰/云质细粒长英沉积岩（C岩）、混积岩（D岩）为主的低孔—特低孔、特低渗储层,主要孔隙类型为溶孔,此外还发育有剩余粒间孔、晶间孔、微裂缝;2）研究区芦草沟组储层孔隙分布复杂,孔径分布曲线呈现多峰形,介孔提供了大部分孔容和比表面积;高压压汞计算的宏孔分形维数均值和氮气吸附计算的介孔分形维数均值分别为：2.864 7、2.507 5,介孔孔隙结构复杂程度相对较低;3）有机质丰度有利于A岩、B岩和C岩宏孔孔隙结构的发育,会导致C岩介孔和D岩孔容、比表面积减小;有机质演化程度对A岩介孔、B岩和C岩介孔起到建设作用,对C岩宏孔、D岩介—宏孔有破坏做用;4）脆性矿物含量越高C岩介孔和D岩孔容比表面积越大,而A岩、B岩宏孔、C岩宏孔孔容、比表面积减小;黏土矿物对A岩介孔、C岩介孔及D岩的孔隙系统发育起到建设作用,对B岩宏孔和C岩宏孔有破坏作用。孔隙结构的发育主要受有机质（有机质丰度、有机质演化程度）和矿物组份（脆性矿物含量、黏土矿物含量）的影响,不同岩性、不同尺度的孔隙发育影响因素各有差异。

     

Tectonometamorphic evolution of the Bohemian Massif: evidence from high pressure metamorphic rocks

The Variscan orogenic belt, of which the Bohemian Massif is a part, is typically recognized for its characteristic low pressure, high temperature metamorphism and a large volume of granites. However, there are also bodies of high pressure rocks (eclogites, garnet peridotites and high pressure granulites) which are small in size but widely distributed throughtout the Massif. Initially the high pressure rocks were considered to be relicts of a much older orogenic event, but the increasing data derived from isotopic and geochronological investigations show that many of these rocks have Palaeozoic protoliths. Metamorphic ages from the high pressure rocks define no single event. Instead, a number of discrete clusters of ages are found between about 430 Ma and the time of the dominant low pressure event at around 320–330 Ma.Most of the eclogite and granulite facies rocks are assigned to allochthonous nappes that arrived close to the end of the low pressure event, but before final granite intrusion. The nappes contain a mixture of different units and the relationship between rocks with high pressure relicts and host gneisses with no apparent signs of deep burial is still problematic. Some of the high pressure rocks retain evidence of multiple stages of partial re-equilibration during uplift. Moreover, it can be shown in certain instances that host gneisses also endured a multistage metamorphic development but with a peak event convergent with one of the breakdown stages in the enclosed rocks with high pressure relicts. It thus appears that the nappe units are composite bodies probably formed during episodic intracrustal thrusting. Fluids derived from prograde dehydration reactions in the newly under thrusting slab are taken to be the catalysts that drove the partial re-equilibrations.On the scale of the whole Massif it can be seen within the units with high pressure relicts that the temperature at the peak recorded pressure and that during the breakdown are variable in different locations. It is interpreted that regional metamorphic gradients are preserved for given stages in the history and thus the present day dismembered nappe relicts are not too far removed from their original spatial distribution in an original coherent unit. From the temperature information alone it is highly probable that the refrigerating underthrusting slab was situated in the north-west. However, this north-west to south-east underthrusting probably represents the major 380–370 Ma event and is no guide to the final thrusting that emplaced the much thinned nappe pile with high pressure relicts.Granite genesis is attributed to the late stage stacking, during the final Himalayan-type collision stage, of thinned crust covered by young, water-rich, sediments — erosion products of the earlier orogenic stages. Regional metamorphism at shallow depths above the voluminous granites was followed by final nappe emplacement which rejuvenated the granite ascent in places. Correspondence to: P. J. O'Brien     

Thermal analysis in the laser-heated diamond anvil cell

A new technique actively controls thermal radiation and monitors sample properties during laser-heating in a diamond anvil cell. The technique can be described as a qualitative application of thermal analysis. Discontinuities in temperature, laser power, visible thermal radiation, or in their derivatives as functions of time can be associated with the enthalpy of phase transitions (such as melting) or with changes in maternal properties (such as emissivity).The technique is illustrated with melting experiments on iron-magnesium-silicate perovskite. Temperature corrections associated with these experiments are discussed and the results are briefly reviewed.     

一种曲线拟合圆心坐标算法及精度分析

针对在工程应用中,经常需要根据某些圆形物体上的离散点求取其圆心坐标,而采用何种算法简单易行,其精度又与哪些因素有关的相关研究较少的问题,该文提出一种利用曲线拟合求取圆心坐标的简洁算法,并编程实现。然后采用模拟仿真结合统计分析的方法评估了该算法在不同条件下的拟合精度,得出测点误差越大,拟合精度越低;测点个数越多,分布越均匀,拟合精度越高;圆半径对拟合精度影响甚小等结论。在某工程项目中使用该算法得到的结果精度较高,验证了其有效可行,且与采用其他方法得到的坐标值较为接近,说明了该算法的可靠性高。     

北斗三号全球导航卫星系统全球广播电离层延迟修正模型(BDGIM)应用性能评估

2020年6月23日,我国北斗三号全球导航卫星系统正式完成星座全球组网.北斗三号全球导航卫星系统采用新一代全球广播电离层延迟修正模型(BDGIM),为用户提供电离层延迟改正服务.本文利用高精度全球电离层格网(GIM)以及实测BDS/GPS数据提供的电离层TEC作为参考,从延迟改正精度及北斗单频伪距单点定位应用、模型系数...     

1+2模式的CORS多系统关键技术的探讨

CORS(Continuously Operating Reference Stations,简称CORS)技术不仅集计算机网络管理技术、INTERNET技术、无线通讯技术和BD/GPS定位技术于一身,而且克服了常规RTK中要求基准站与流动站间距较近的缺陷,所以它将会是未来BD/GPS发展的一个方向。本文就目前着手的兼容GPS/BD的CORS建设的科技项目,对多模系统的CORS建设的关键技术和难点做了详细的分析。