Advances, Problems and Prospects of Modern Geodesy Applied in Tibetan Geodynamic Changes

Modern geodetic techniques have developed rapidly in recent years, providing reliable observation data and new effective approaches, and greatly enhancing studies of the Tibetan geodynamics. For instance, the well-known GPS technique has been employed to measure seismic slips for many faults in the Tibetan Plateau. GPS data agree well with the hypothesis of a thickening crust and eastward mass flow. Moreover, absolute gravimetric data have been applied to interpret geophysical phenomena such as crust movement, co-seismic gravity change, GIA, and ground water change. The satellite gravity mission GRACE launched in 2002 provided global gravity models with unprecedentedly high precision and high spatial resolution. It has been used in implementing temporal gravity changes and improving our knowledge of the Earth’s interior, including lithosphere dynamics, mantle viscosity and rheology, plateau uplift, and subduction processing. It is noteworthy that gravity presents unique advantages for the study of Tibetan geodynamics because of its sensitivity to mass migration and dynamic redistribution. To date, great advances have been made in applying modern geodetic data in studying dynamic changes of Tibetan plateau. For instance, the horizontal displacement field from GPS data revealed dynamical characteristics of the present-day Tibetan plateau. The combination of gravity anomalies and topographic data describe the tectonic characteristics of Tibetan plateau. The combination of gravity data and GPS data show present properties of the Tibetan plateau such as crust thickening, Moho’s subsidence, and plateau uplift. GRACE data were used to estimate the distribution of ice/snow melting.     

浅谈GPS建立精密工程控制网、广播星历误差对相对定位精度的影响

通过某厂二种常规方法获得的成果与GPS网分别用广播星历（随机商用软件）、精密星历（精密软件）处理采集数据获得成果对比,研究GPS定位技术建立精密控制网和广播星历（随机软件）误差对相对定位精度的影响。     

GPS-measured land subsidence in Ojiya City, Niigata Prefecture, Japan

Land subsidence caused by compression of clay layers in Ojiya City, Japan was measured by global positioning system (GPS) between 1 April 1996 and 31 December 1998.

Three baselines were selected in and around the city, and height difference on a WGS-84 ellipsoid was measured by GPS on each baseline. The ground at the GPS station in the city subsides and rebounds 7 cm every winter and spring, respectively. Measurement accuracy was 9.5 mm standard deviation. Ground water level was observed at a well near the GPS station. Regression analysis between total strain, calculated as ratio of the height difference displacement to the total thickness of the clay layers, and the layers' effective stress change with ground water level change gave good correlation. The slope of regression line 7.0×10⁻¹¹ m²/N was obtained as an average apparent coefficient of volume compressibility of the layers.     

磐石市矿业权实地核查测量技术总结

本文通过对磐石市矿业权实地核查测量工作的总结,对矿业权实地核查中测量技术的方法进行了全面介绍和系统阐述,为矿业权核查的顺利进行提供了良好的理论支持,同时也为今后类似测绘项目提供了宝贵的实践经验。     

Recent landslide activity in Manaihan,East Belgium

Past landslides have been recognized in the Battice area in E-Belgium. In contrast to the other inactive landslides, the Manaihan landslide responded immediately to heavy rainfall events in the last two decades. This study aims to map its spatial extent and the dominant surface features; to measure surface displacement using GPS; to investigate subsurface structure with Cone penetration test (CPT) and corings; and to determine the depth of the shear surface by inclinometers. Results show a partial landslide reactivation. Surface velocities range between 20 and 40 cm/year and are strongly dependent on winter rainfall. CPT results give clear boundaries between the landslide mass and the undisturbed bedrock in the head scarp. Distinct shear surfaces have been determined with displacement rates up to 15.8 mm in 21 days. Further research should apply geophysical methods for two-dimensional information on the ground, investigate geotechnical properties of the landslide mass, model slope instability, and determine the influence of a sewage pipe crossing the central landslide mass as a potential cause for landslide activity.     

埕岛油田海域气象规律研究与应用

气象海况是组织海上油田生产的重要依据,通过查询海区历史气象资料,分析研究埕岛油田海域的气象规律和特点,紧密结合油田区城地理、海上施工及平台、船舶等设施及装备的基本情况,针对油田生产、海上施工等受气象水文因素制约、影响的不同特点,提出科学的组织生产措施,提高生产效率,保障安全生产。     

南海东北部新构造运动及其动力学机制

南海东北部地处欧亚板块与菲律宾海板块的交汇区,新构造运动活跃。根据地震活动性、震源机制解和GPS资料对该区的新构造活动特征进行分析,在此基础上讨论该区新构造运动的动力学机制。分析发现,菲律宾海板块NW向俯冲对该区的影响最为显著,导致了该区较强的地震活动性以及与俯冲方向一致的构造应力场。而印藏碰撞产生的侧向应力传递也影响到该区,控制华南地块向SE方向运动,并与菲律宾海板块的NW向俯冲共同作用,使华南地块在SE向运动的同时伴有逆时针旋转。印藏碰撞的SE向应力传递对俯冲产生的NW向水平挤压的抵消作用,使得地震活动性自东向西减弱以及构造应力场P轴方位角顺时针旋转。在这一背景下,区内滨海断裂带的活动控制了该区的地震、海岸带构造升降等新构造运动。     

利用卫星云图资料制作热带气旋预报路径的一种算法

根据台风生成后在云场中移动的环境条件,引入一个环境作用于台风中心的热力梯度力方向,用该热力梯度力方向与当前台风的移动方向相结合,研究台风移动过程的变化规律,寻找一种简易可行的台风路径预报方法．经过多年实践,本文揭示出台风中心未来沿着当前移动方向与环境作用于台风中心的热力方向合成移动的基本规律：当前台风中心移向与前方晴空区中轴线相交时,台风沿着当前移向前进到与阻挡轴线相交点相距4个纬距的位置时便发生偏转,逐渐与阻挡轴线走向趋于一致;若当前台风中心距相交点的距离小于或等于4个纬距时,则从当前位置发生偏转．文中利用以上规律研制出台风移向变化方程和移动轨迹方程．     

移动GIS技术在土地变更调查中的应用

介绍了GPS定位的高精度和PDA的便于携带、功能强大的特点,将二者集成用于土地变更调查。探讨了移动GIS应用于土地变更调查的技术方法,移动GIS的系统结构及其开发实践。     

A drought outlook study in Korea

Abstract

Techniques are proposed for developing a monthly and weekly drought outlook and the drought outlook components are evaluated. A drought index, the surface water supply index (SWSI) was modified and used for the drought outlook. A water balance model (abcd) was successfully calibrated using a regional regression, including monthly and weekly factors, and was used to convert meteorology to hydrology. For the monthly drought outlook, an ensemble technique was applied, both with and without monthly industrial meteorology information (MIMI). For the weekly drought outlook, a deterministic forecasting technique was applied employing the Global Data Assimilation and Prediction System (GDAPS). The methodologies were applied to the Geum River basin in Korea. While only the weekly outlook using the GDAPS has sufficient forecasting capability to suggest it might be useful, the accuracy of the monthly drought outlook is expected to improve as the climate forecast accuracy increases.

Editor Z.W. Kundzewicz; Associate editor D. Hughes

Citation Kim, Y.-O., Lee, J.-K., and Palmer, R.N., 2012. A drought outlook study in Korea. Hydrological Sciences Journal, 57 (6), 1141–1153.