地磁偏角实时自动修正技术在油田定向钻井中的应用   总被引：2，自引：1，他引：2  

夏国辉  张凤玉 《地球物理学进展》1995,10(2):95-98

在油田定向钻井的磁导向定位系统中，地磁偏角校正是一个不可缺少的基本要素，同时在磁偏角校正值精度直接影响定向井的导向定位精度。因此，作者提出了提高地磁偏角校正值精度的方法，并试图将地磁偏角实时自动修正技术引入我国油田定向钻井领域。  相似文献   

Measuring magnetic field in the 'diamagnetic' ionosphere     

F. J. Lowes 《Geophysical Journal International》2007,171(1):115-118

Satellite magnetometers sometimes pass through regions of plasma, such as the terrestrial ionosphere, where the ionization is large enough that some of the original ambient field is excluded from the plasma. This reduction of field inside the plasma region comes from the 'diamagnetic' effect of the charged particles in their helical trajectory around the magnetic field lines. The (container of the) magnetometer will exclude the plasma, and a simple-minded approach, treating the ionosphere in the same way as for a conventional diamagnetic fluid, predicts that the field seen by the magnetometer will be somewhat larger than the (reduced) field in the plasma. However, the 'diamagnetic' properties of the ionosphere are quite different from those of a conventional diamagnetic. In particular, there is a 'reflection' of the ionospheric charged particles at the surface of the magnetometer, and the overall effect is that the magnetometer does actually measure the field present in the plasma before the magnetometer is inserted. Similarly, any leakage fields from the magnetometer have no effect in the magnetosphere.  相似文献   

Tests of core flow imaging methods with numerical dynamos     

Hagay Amit  Peter Olson  Ulrich Christensen 《Geophysical Journal International》2007,168(1):27-39

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Bootstrapped discrete scale invariance analysis of geomagnetic dipole intensity     

Art R. T. Jonkers 《Geophysical Journal International》2007,169(2):646-658

The technique of bootstrapped discrete scale invariance allows multiple time-series of different observables to be normalized in terms of observed and predicted characteristic timescales. A case study is presented using the SINT2000 time-series of virtual axial dipole moment, which spans the past 2 Myr. It is shown that this sequence not only bears a clear signature of a preferred timescale of about 55.6 Ka, but additionally predicts similar features (of shorter and longer duration) that are actually observed on the timescales of historical secular variation and dipole reversals, respectively. In turn, the latter two empirical sources both predict the characteristic timescale found in the dipole intensity sequence. These communal scaling characteristics suggest that a single underlying process could be driving dynamo fluctuations across all three observed timescales, from years to millions of years.  相似文献   

Semi-active model predictive control for 3rd generation benchmark problem using smart dampers     

颜桂云  孙炳楠  吕艳平 《地震工程与工程振动(英文版)》2007,6(3):307-315

A semi-active strategy for model predictive control (MPC), in which magneto-rheological dampers are used as an actuator, is presented for use in reducing the nonlinear seismic response of high-rise buildings. A multi-step predictive model is developed to estimate the seismic performance of high-rise buildings, taking into account of the effects of nonlinearity, time-variability, model mismatching, and disturbances and uncertainty of controlled system parameters by the predicted error feedback in the multi-step predictive model. Based on the predictive model, a Kalman-Bucy observer suitable for semi-active strategy is proposed to estimate the state vector from the acceleration and semi-active control force feedback. The main advantage of the proposed strategy is its inherent stability, simplicity, on-line real-time operation, and the ability to handle nonlinearity, uncertainty, and time-variability properties of structures. Numerical simulation of the nonlinear seismic responses of a controlled 20-story benchmark building is carried out, and the simulation results are compared to those of other control systems. The results show that the developed semi-active strategy can efficiently reduce the nonlinear seismic response of high-rise buildings.  相似文献   

Ionospheric effetcs of an intense geomagnetic storm     

G. A. Mansilla 《Studia Geophysica et Geodaetica》2007,51(4):563-574

An investigation of the response of the mid-high, mid and low latitude critical frequency foF2 to the geomagnetic storm of 15 July 2000 is made. Ground-based hourly foF2 values (proportional to square root of peak electron density of F2-layer) from four chains of ionospheric stations located in the geographic longitude ranges 10°W–35°E, 60°E–120°E, 130°E–170°E, 250°E–295°E are used. Relative deviations of foF2 are considered. The main ionospheric effects for the considered storm are: long-duration negative disturbances at mid-high latitudes in summer hemisphere in sectors where the storm onset occurred in the afternoon/night-time hours; short-duration positive disturbances in the summer hemisphere at mid-high latitudes in the pre-sunset hours during the end of main phase-first stage of the recovery; small and irregular negative disturbances in the low latitude winter hemisphere which predominate during the main phase and first part of the recovery, and positive disturbances in both hemispheres at mid-high and mid latitudes prior to the storm onset irrespective of the local time. In addition, the validity of some physical mechanisms proposed to explain the F2 region behaviour during disturbed conditions is considered. gus-mansilla@hotmail.com  相似文献   

The structure of the mid- and high-latitude ionosphere during the November 2004 storm event obtained from GPS observations   总被引：1，自引：1，他引：1  

Andrzej Krankowski  Irk I. Shagimuratov  Lubomir W. Baran  Galina Yakimova 《Acta Geophysica》2007,55(4):490-508

GPS data from the International GNSS Service (IGS) network were used to study the development of the severe geomagnetic storm of November 7–12, 2004, in the total electron content (TEC) on a global scale. The TEC maps were produced for analyzing the storm. For producing the maps over European and North American sectors, GPS measurements from more than 100 stations were used. The dense network of GPS stations provided TEC measurements with a high temporal and spatial resolution. To present the temporal and spatial variation of TEC during the storm, differential TEC maps relative to a quiet day (November 6, 2004) were created. The features of geomagnetic storm attributed to the complex development of ionospheric storm depend on latitude, longitude and local time. The positive, as well as negative effects were detected in TEC variations as a consequence of the evolution of the geomagnetic storm. The maximal effect was registered in the subauroral/auroral ionosphere during substorm activity in the evening and night period. The latitudinal profiles obtained from TEC maps for Europe gave rise to the storm-time dynamic of the ionospheric trough, which was detected on November 7 and 9 at latitudes below 50°N. In the report, features of the response of TEC to the storm for European and North American sectors are analyzed.  相似文献   

关于地球磁场极性反转机制的思索     

杨合群 《西北地质》2002,35(3):126-130

地球磁场极性在地质历史中发生过相当频繁的倒转。作者将地球内部划分为岩石圈－软流圈－中圈－液圈－固核等5个动力学圈层，认为中圈与固核间可异步旋转；地球偶极磁场由中圈与固核异步旋转时所驱动的液圈中的封闭涡流与系磁场作用产生；该偶极子场极性由地球所通过的银道面上侧或下侧磁场方向及液圈涡流的方向共同决定，二者之一反向，极性发生倒转。  相似文献   

通海地磁台(L=1.03)Pc3地磁脉动的出现率     

韩德胜  高玉芬  张福  P.J.Chi 《地震地磁观测与研究》2001,22(5):16-21

利用通海地磁台(L=1．03)1999年SMALL磁通门磁力仪记录资料，对Pc3脉动出现率的统计结果表明，日出现频次有两个峰值，即清晨06：00-07：00LT(地方时)出现频次最高，午后14：00～15：00LT为次峰值。Pc3脉动月出现频率最高的是4月和12月，其次是8月和9月；最少的是6月和7月。按季节统计结果为春秋季出现频次最高，冬季次之，夏季最低。  相似文献   

建立南极站区环境管理信息系统的初步研究          下载免费PDF全文

李瑞秋  赵俊琳 《极地研究》2001,13(2):137-150

南极环境对人类生存具有举足轻重的作用。南极环境管理是保护南极环境和保证持续利用南极资源的必要手段 ,信息技术在南极环境管理中的应用必将极大地推动南极环境管理的进步。本文为提高我国南极环境管理的科学性和效率 ,根据南极环境、南极环境管理以及南极站区人类活动的特点 ,尝试研究开发了南极站区环境管理信息系统 ( ASEMIS:Antarctic StationEnvironmental Management Information System)。ASEMIS具有管理、模拟、利用南极站区环境、南极站区人类活动等有关信息的功能  相似文献