An example of identifying karst groundwater flow

 Hydrogeological investigations for the purpose of regulating the karst aquifer were carried out in the mountain massif of Kucaj in the Carpatho-Balkan range of eastern Serbia. Different geophysical methods were applied in order to identify the position of karstified zones with active circulation of karst underground streams. Especially good results were obtained by using the spontaneous potential method for the exploration and construction of boreholes and wells. In the valleys of Crni Timok and Radovanska reka the measurements have been carried out upstream along the whole width of the alluvium to the limestone periphery. A number of positive and negative anomalies have been recorded. In the centres of positive anomalies several boreholes were located: HG-19 (centre of anomaly +30 mV, total length of the biggest cavern is 9 m); HG-1 (+20 mV, cavern of 2 m); HG-15 (max. +114 mV, effective cavernousness is 17%). Received: 20 February 1995 · Accepted: 12 September 1997     

广西清明山铜镍硫化物矿床上升气流微粒研究

为探讨上升气流微粒与深部隐伏矿体之间关系,在广西清明山铜镍硫化物矿床上方土壤中采集上升气流微粒,并采用透射电子显微镜(TEM)对微粒的形貌、大小、聚合状态、化学组分及结构等进行分析。结果表明,微粒主要由Cu、Co、Zn、Fe、Ca、Si、S等元素组成,其中成矿元素Cu、Co以自然Cu-Fe-Co、Zn-Fe-Co及Fe-Co合金微粒的形式存在,其余如Fe、Ca、Si、S等元素则以氢氧化物、氧化物及碳酸盐微粒形式存在。微粒可分为微粒聚合体及单个微粒,微粒的大小为50~500nm,微粒的形状多为不规则状、近椭圆形、近球状、水滴状和近长方体等。微粒中高含量的Cu、Co、Zn来源于深部隐伏矿体,含Fe、S微粒来源于矿床中金属硫化物矿物。此外,高价态的微粒组分指示微粒处于相对氧化的环境。清明山铜镍硫化物矿床的上升气流微粒组分与矿床矿物组分间存在着较好的对应性,本研究为隐伏铜镍硫化物矿床提供了新的找矿方法。     

SEISMICITY TENDENCY PREDICTION BEFORE 2020 IN CHINA MAINLAND FROM ASTRONOMIC PERIODICITIES

The correlations between large earthquakes in China continent and periodicities of the Moon's movement and the solar activity are statistically analysed and the following points are revealed:1. The earthquakes with ≥7.5 in Qing-Zang fault-block region have 18.6-yr periodicity of the Moon's nodes motion.2. The earthquakes with M≥7.1 in Xinjiang fault-block region have 8.85-yr periodicity of the Moon's perigee motion.3. The earthquakes with M≥7.0 in China mainland have the tendency to cl     

Wave effects on ascending and descending motions of the autonomous underwater vehicle

In the paper, a hydrodynamic model including the characteristics of maneuvering and seakeeping is developed to simulate the six-degree of freedom motions of the underwater vehicle steering near the sea surface. The corresponding wave exciting forces on the underwater vehicle moving in waves are calculated by the strip theory, which is based on the source distribution method. With the hydrodynamic coefficients relevant to the maneuvering and seakeeping, the fourth-order Runge–Kutta numerical method is adopted to solve the equations of motions and six-degrees of freedom of the motions for the underwater vehicle steering near the free surface can be obtained. The wave effect on the corresponding motions of the underwater vehicle is investigated and some interesting phenomena with respect to different wave frequencies and headings are observed. The hydrodynamic numerical model developed here can be served as a valuable tool for analyzing the ascending and descending behaviors of the underwater vehicle near the sea surface.     

Two-sided long baseline radargrammetry from ascending-descending orbits with application to mapping post-seismic topography in the west Sichuan foreland basin

One-sided ascending or descending Synthetic Aperture Radar（SAR） stereoradargrammetry has limited accuracy of topographic mapping due to the short spatial baseline（-100 km） and small intersection angle. In order to improve the performance and reliability of generating digital elevation model（DEM） from spaceborne SAR radargrammetry, an exploration of two-sided stereoradargrammetry from the combination of ascending and descending orbits with geometric configuration of long spatial baseline（-1000 km） was conducted in this study. The slant-range geometry between SAR sensors to the earth surface and the Doppler positioning equations were employed to establish the stereoscopic intersection model. The measurement uncertainty of two-sided radargrammetric elevation was estimated on the basis of radar parallax of homogeneous points between input SAR images. Two stereo-pairs of ALOS/PALSAR（Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar） acquisitions with the orbital separation almost 1080 km over the west Sichuan foreland basin with rolling topography in southwestern China were employed in the study to obtain the up-to-date terrain data after the 2008 Wenchuan earthquake that hit this area. Thequantitative accuracy assessment of two-sided radargrammetric DEM was performed with reference to field GPS observations. The experimental results show that the elevation accuracy reaches 5.5 m without ground control points（GCPs） used, and the accuracy is further improved to 1.5 m with only one GPS GCP used as the least constraint. The theoretical analysis and testing results demonstrate that the twosided long baseline SAR radargrammetry from the ascending and descending orbits can be a very promising technical alternative for large-area and high accuracy topographic mapping.     

石家庄一次秋季罕见暴雪天气过程物理诊断分析

利用NCEP再分析资料,采用天气学诊断方法,对2009年11月10—12日石家庄地区出现的一次历史同期罕见区域性暴雪天气过程的环流特征和物理量场进行了探讨。结果表明：此次暴雪天气过程属典型的东北回流型降雪,地面从贝加尔湖南下冷高压与河套低压倒槽、700 hPa暖式切变线、500 hPa高空槽是主要影响系统。低空西南急流与超低空东北急流耦合,在为暴雪提供水汽和热量输送的同时加强了抬升运动。水汽的垂直输送导致局地比湿显著增大,深厚的湿层和强烈的水汽辐合为暴雪提供了充沛的水汽条件。“高空辐散、低空辐合”以及强劲的上升运动是暴雪的动力条件,降雪强度最大时段对应上升运动的强盛发展阶段。暴雪开始阶段云水含量的时空演变特征,一方面显示了水汽的迅速增加与爬升,另一方面也说明了地形的强迫抬升作用不容忽视。850 hPa温度低于700 hPa,有利于水汽经过此层时被凝华成固态。逆温层提前24 h出现,而且暴雪最强时段内两层温差均为5 ℃以上,这对暴雪预报具有指示意义。     

华北一次西南涡暴雨过程的诊断分析

利用一日4次1°×1°的NCEP再分析资料和常规观测资料,分析了2010年7月19日发生在华北地区的西南涡暴雨过程。结果表明：此次暴雨过程是不同尺度系统共同影响的结果,低空急流将水汽源源不断地向暴雨区输送,云水含量大值区与强上升运动和强降水时段有较好的对应关系,高、低空急流的耦合作用促进了上升运动,暴雨期间对流层低层有自南向北发展的高能舌维持,存在对流性不稳定层结,上升运动自低层向上发展,将低层的暖湿空气向上输送,使得大量的不稳定能量释放,为暴雨区提供了持续的能量。     

地气测量寻找深部隐伏金矿及其机理研究

根据９个地区４种不同的金和金多金属矿区地气研究、室内上升气流和纯扩散模拟模型实验以及地气采样片在高分辨显微技术（ＡＦＭ,ＴＥＭ,ＳＥＭ）下观察的结果,讨论了地气测量的找矿机理,认为地壳内上升气流携带深部矿化元素的纳米级微粒垂直向上迁移至地表,形成地气异常．文中对地气法的方法技术做了概述和评论,并列举了应用实例,地气法兼有物、化探的优点,在寻找深部隐伏矿化方面具有广阔的应用前景。     

西藏改则地震升降轨同震形变场特征分析与破裂模式

通过升降轨ASAR数据的获取与差分干涉处理,获取了西藏改则地震的双视线向同震形变场信息。对升降轨同震形变场的特征分析表明,改则地震主、余震均表现为典型的正断裂破裂模式,并先后形成了东、西两条规模不同的走向NE、倾向NW的正断层破裂带(可能未出露地表),以及西北盘的东、西两个沉降形变中心。从干涉条纹的切割关系判断,东沉降形变中心可能受2008年1月9日Ms 6.9级主震的控制,西沉降形变中心可能受2008年1月16日Ms 6.0级余震的控制。Ms 6.9级主震形成东南盘隆升与西北盘沉降的总体格局;Ms 6.0级余震使西北盘余震震中及以西部位进一步沉降,造成西沉降中心沉降形变量大于东沉降中心。升降轨同震形变场的获取为进一步的震源参数模拟与三维形变场解算提供了更好的约束条件与信息。     

Evaluation of SMOS soil moisture retrievals over the central United States for hydro-meteorological application

Soil moisture has been widely recognized as a key variable in hydro-meteorological processes and plays an important role in hydrological modelling. Remote sensing techniques have improved the availability of soil moisture data, however, most previous studies have only focused on the evaluation of retrieved data against point-based observations using only one overpass (i.e., the ascending orbit). Recently, the global Level-3 soil moisture dataset generated from Soil Moisture and Ocean Salinity (SMOS) observations was released by the Barcelona Expert Center. To address the aforementioned issues, this study is particularly focused on a basin scale evaluation in which the soil moisture deficit is derived from a three-layer Xinanjiang model used as a hydrological benchmark for all comparisons. In addition, both ascending and descending overpasses were analyzed for a more comprehensive comparison. It was interesting to find that the SMOS soil moisture accuracy did not improve with time as we would have expected. Furthermore, none of the overpasses provided reliable soil moisture estimates during the frozen season, especially for the ascending orbit. When frozen periods were removed, both overpasses showed significant improvements (i.e., the correlations increased from r = −0.53 to r = −0.65 and from r = −0.62 to r = −0.70 for the ascending and descending overpasses, respectively). In addition, it was noted that the SMOS retrievals from the descending overpass consistently were approximately 11.7% wetter than the ascending retrievals by volume. The overall assessment demonstrated that the descending orbit outperformed the ascending orbit, which was unexpected and enriched our knowledge in this area. Finally, the potential reasons were discussed.