共查询到20条相似文献,搜索用时 78 毫秒
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中国地磁监测网由地磁台站和流动地磁测点构成,实现对观测网内地磁场的相对记录和绝对观测。它的绝对观测采用世界上最先进的F、D、I测量仪器组合,其中地磁偏角D是地理北和地磁北的夹角。对地磁偏角D的绝对测量要求在地磁台站投入正常观测前必须完成观测墩和观测标志的地理方位角测量,流动地磁测点在每次地磁偏角D观测前后至少进行地理方位角测量各一次。据地磁监测网《观测规范》要求,地磁偏角D的观测精度必须≤6″,所以中国地磁监测网采用天文和差分GPS地理方位角两种测量方法,且两种方法观测精度相当,均≤6″。与天文测量相比,差分GPS观测不受天气等自然因素的限制,操作简单,观测快捷,数据处理计算机程序化。随着GPS技术的普及,中国地磁监测网差分GPS地理方位角测量方法已基本取代了天文方法。本文主要介绍差分GPS在中国地磁监测网地理方位角测量中的应用。 相似文献
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为了进一步改善和提高乌鲁木齐地震台地磁资料观测精度,于1989年9月在乌鲁木齐地震台新修建了两个地磁测量标志。为保证新标志的观测精度和长期稳定性,在选点、设计和施工中,国家地震局地球物理研究所九室的周锦屏,赵学敏等同志进行了指导。标志建成后经过一年时间的保养维护,标志已处于稳定状态。标志方位角是测量磁偏角不可少的一个参照量,它的准确性以及长其稳定性直接关系到磁偏角的观测精度。建台时修建的两个测量标志由于在设计处理中没有直接和基岩相接触,所以经过十几年时间的变化影响,标志向一方倾斜,方位角发生了近1°7′的变化,给该台磁偏角观测带来了不应有的测量误差。另外,作为国家地磁一 相似文献
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FHD 磁力仪分量线圈装置误差对磁偏角观测的影响分析 总被引:1,自引:1,他引:0
根据FHD 磁力仪观测磁偏角的原理, 计算了分量线圈不水平导致的磁偏角观测值误差,发现分量线圈仅在EW 方向的倾斜对磁偏角观测产生误差。文中将理论分析结果与实际观测结果进行了对比分析, 发现由于分量线圈底座水平的长期漂移, 仪器的垂直分量及磁偏角观测误差也会发生长期漂移, 长期漂移变化的周期约2 ~ 4 个月, 对垂直分量其幅度约3.5~ 11.0nT, 而磁偏角的幅度约0.1′~ 1.0′, 因此认为在将该仪器观测值用作绝对观测值进行地震异常分析时, 应注意回避这种长期漂移变化。 相似文献
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本文主要介绍了用普通便携式磁力仪独立测定天文方位角,方法简便,为今后地磁台站核查标志方位问题作了先例。这种方法在目前观测磁偏角和流动磁测工作中可以广泛采用. 相似文献
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朱兆才 《地震地磁观测与研究》1989,10(4):54-57
本文讨论了使用CJ_6型磁力仪测定磁偏角中的几个问题。认为仪器材料磁性影响、仪器置平程度好坏、望远镜聚焦位置改变,正、倒镜读数差大小、悬丝扭力大小以及磁系翻转复位率都可以对观测结果产生影响。作者提出了在观测中提高磁系翻转复位率的几项措施,并对CJ_6型磁力仪的观测和仪器改进提出了有关建议。 相似文献
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M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities. 相似文献
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《地震工程与工程振动(英文版)》2014,(4)
正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and 相似文献
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George W. Housner 《地震工程与工程振动(英文版)》2008,7(2):I0001-I0001
Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States. 相似文献
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《国际泥沙研究》2014,(4)
正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study 相似文献
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JianCheng Shi 《中国科学:地球科学(英文版)》2014,57(10):2281-2282
正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases 相似文献