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Firstly, the new single and combined error models applied to estimate the cumulative geoid height error are efficiently produced by the dominating error sources consisting of the gravity gradient of the satellite-equipped gradiometer and the orbital position of the space-borne GPS/GLONASS receiver using the power spectral principle. At degree 250, the cumulative geoid height error is 1.769 × 10?1 m based on the new combined error model, which preferably accords with a recovery accuracy of 1.760 ×10?1 m from the GOCE-only Earth gravity field model GO_CONS_GCF_2_TIM_R2 released in Germany. Therefore, the new combined error model of the cumulative geoid height is correct and reliable in this study. Secondly, the requirements analysis for the future GOCE Follow-On satellite system is carried out in respect of the preferred design of the matching measurement accuracy of key payloads comprising the gravity gradient and orbital position and the optimal selection of the orbital altitude of the satellite. We recommend the gravity gradient with an accuracy of 10?13?10?15 /s2, the orbital position with a precision of 1-0.1 cm and the orbital altitude of 200-250 km in the future GOCE Follow-On mission. 相似文献
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Bekhterev S. V. Drobyshev M. N. Zheleznyak L. K. Koneshov V. N. Mikhailov P. S. Solov’ev V. N. 《Izvestiya Physics of the Solid Earth》2019,55(5):806-810
Izvestiya, Physics of the Solid Earth - Abstract—The empirical results on estimating the resolution and high-frequency noise in the Earth’s gravity models are presented. The Schmidt... 相似文献
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Numerical Studies on the Harmonic Downward Continuation of Band-Limited Airborne Gravity 总被引:1,自引:0,他引:1
In this paper, the numerical stability and efficiency of methods of harmonic downward continuation from flying altitudes are treated for sampled gravity field data. The problem is first formulated in its continuous form, i.e. as the inverse solution of the spherical Dirichlet problem, and is then approximated by Gaussian quadrature to yield a finite system of linear equations. The numerical stability of this system is investigated for both error-free gravity data and for the noisy and band-limited gravity measurements usually obtained from airborne gravity surveys. It can be shown that the system becomes ill-conditioned, once the ratio between flying altitude and data sampling rate exceeds a certain limit. It can also be shown that noisy measurements tend to generate a solution that is practically useless, long before the system becomes ill-conditioned. Therefore, instead of treating the general solution of the discrete downward continuation problem, the more modest question is studied, for which range of flying altitudes and sampling rates, the numerical solution of the discrete linear system can be considered as practically useful. Practically useful will be defined heuristically as of sufficient accuracy and stability to satisfy the requirements of the user. The question will be investigated for the specific application of geoid computation from gravity data sampled at flying altitudes. In this case, a stable solution with a standard deviation of a few centimeters is required. Typical flight parameters are heights of 2–6 km, a minimum half-wavelength resolution of 2 km, and data noise between 0.5 and 1.5 mGal. Different methods of geoid determination, different solution techniques for the resulting systems of linear equations, and different minimization principles will be compared. As a result operational parameters will be defined which, for a given noise level, will result in a geoid accuracy of a few centimeters for the estimated band-limited gravity field spectrum. 相似文献
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Two integral transformations between the stress function, differentiation of which gives the meridian and prime vertical components of the sub-crustal stress due to mantle convection, and the satellite-to-satellite tracking (SST) data are presented in this article. In the first one, the SST data are the disturbing potential differences between twin-satellites and in the second one the line-of-sight (LOS) gravity disturbances. It is shown that the corresponding integral kernels are well-behaving and therefore suitable for inversion and recovery of the stress function from the SST data. Recovery of the stress function and the stress components is also tested in numerical experiments using simulated SST data. Numerical studies over the Himalayas show that inverting the disturbing potential differences leads to a smoother stress function than from inverting LOS gravity disturbances. Application of the presented integral formulae allows for recovery of the stress from the satellite mission GRACE and its planned successor. 相似文献
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根据月球与太阳相对于地球位置的关系,建立一个三维正交分解模型来揭示重力固体潮中包含的谐波成分。在此基础上,提出一种基于单形邻域与多角色进化策略智能优化算法的独立分量分析方法,用以提高算法效率和全局寻优能力;并结合谱相关方法,对重力固体潮观测数据进行处理和分析,观察其频域和时域的变化。最后引入理论信号和理论计算值作为参考背景,以凸显其异常变化特征。研究表明,利用该方法可以有效地反映出重力固体潮潮汐的日波、半日波、长周期波等特征。同时,发现重力固体潮潮汐的异常变化中隐含有地震前兆信息,通过对云南地区观测数据的分析,在排除测量误差和环境影响外,发现在地震前2~5个月内,重力固体潮的长周期波均呈现出规律性的异常变化。这反映出地震的前兆异常信息,可能对地震时间和地点的预测提供依据。 相似文献
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多网重力数据联合平差和系统误差改正 总被引:1,自引:0,他引:1
华北地区现行的地震重力监测网由于独立联测, 自成体系, 绝对控制点较少, 获得的重力场动态变化图像在绝对控制较弱的地区会产生畸变, 也不能有效的消除仪器标定系统所引起的测量误差。 本文以华北大网作为控制网, 结合绝对重力点进行联合平差计算, 使各省区地震重力监测网平差精度提高了(0~4)×10-8 m/s2, 平差起算基准相统一, 绝对控制较弱的地区畸变减小。 采用相关系数检验法, 对华北地区各省区地震重力监测网2010年二期重力平差计算结果进行检验, 部分重力点位系统误差高达60×10-8 m/s2, 经过系统误差改正后, 重力场动态变化趋于一致。 经过各项改正后, 华北地区2010年重力场动态差分图像对地震前兆具有更好的反映。 相似文献
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Christian Hirt Sten J. Claessens Michael Kuhn Will E. Featherstone 《Studia Geophysica et Geodaetica》2012,56(4):957-975
Curtin University??s Mars Gravity Model 2011 (MGM2011) is a high-resolution composite set of gravity field functionals that uses topography-implied gravity effects at medium- and short-scales (??125 km to ??3 km) to augment the space-collected MRO110B2 gravity model. Ground-truth gravity observations that could be used for direct validation of MGM2011 are not available on Mars??s surface. To indirectly evaluate MGM2011 and its modelling principles, an as-close-as-possible replication of the MGM2011 modelling approach was performed on Earth as the planetary body with most detailed gravity field knowledge available. Comparisons among six ground-truth data sets (gravity disturbances, quasigeoid undulations and vertical deflections) and the MGM2011-replication over Europe and North America show unanimously that topography-implied gravity information improves upon space-collected gravity models over areas with rugged terrain. The improvements are ??55% and ??67% for gravity disturbances, ??12% and ??47% for quasigeoid undulations, and ??30% to ??50% for vertical deflections. Given that the correlation between space-collected gravity and topography is higher for Mars than Earth at spatial scales of a few 100 km, topography-implied gravity effects are more dominant on Mars. It is therefore reasonable to infer that the MGM2011 modelling approach is suitable, offering an improvement over space-collected Martian gravity field models. 相似文献
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The non-tidal variation gained from continuous gravity observations in stations usually reflects the regional continuous gravity changes. In this paper we focus on studying the non-tidal variation of Baijiatuan station, Beijing where there are two different gravimeters (namely, L&R-804 and PET-031). Based on the original raw tidal records of two gravimeters from 2008 to 2011, we first remove various interference from raw data by the standard procedure software-Tsoft; then we model the solid earth tides, ocean tidal loading and pole tide through related parameters; after that we adopt a new segmented polynomial fitting method based on Tsoft to fit the complex drift of spring gravimeter; and finally we calculate the atmospheric loading effects by a linear regression model. After a series of processing we gain the non-tidal variation of the two gravimeters at Baijiatuan site, Beijing. Furthermore, to analyze the non-tidal variation preliminarily, we study the main component of related tidal data by power spectral density. Comparing the non-tidal variation of two different gravimeters, we find seasonal fluctuations in non-tidal results, which are in accordance with the water storage change. Therefore, we take into account the relevance of gravity changes and water storage based on the gravity data of GRACE and water data of the CMAP model from 2003 to 2011 at different sites in the Chinese mainland (Beijing, Chengdu, Shenyang and Shiquanhe) , and make a preliminary analysis on the relationship between gravity changes and water storage. 相似文献
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利用2018年庐山重力短基线场绝对重力和相对重力观测资料,基于绝对重力控制下的相对重力联测方式对庐山基线场的稳定性进行了分析。结果表明:庐山基线场2015~2018年测段重力变化为-11.6~13.4μGal、均值-0.962μGal,较小的重力变化表明庐山短基线重力场较稳定;2000~2018年测段重力变化为-39~33.5μGal、均值-0.275μGal,总体以G16测点为界呈分化特征,上山侧(G16~JZ04)重力变化较平缓(约-3 μGal),下山侧(G03~G16)因G04、G14测点重力值变化显著(分别为-24.95、-18.5μGal),导致相邻测段重力变化剧烈;测段重力变化与段差比值(B)为1.19×10-4~3.58×10-3;庐山及其周边地区由地表垂直运动引起的重力变化速率为0.7543±0.16μGal/a;近期研究区地震活动性呈震级小、沿断裂带集中分布特征;重力变化对相对重力仪一次项系数标定结果影响较大(正比于B值),对校正精度影响小,利用以往重力观测成果进行一次项系数标定时,绝对重力测段JZ02~JZ04误差影响小于最大重力段差测段,定期维护和复测是保障高精度重力短基线场的有效途径。 相似文献
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Comparison of Daily GRACE Gravity Field and Numerical Water Storage Models for De-aliasing of Satellite Gravimetry Observations 总被引:1,自引:0,他引:1
L. Zenner I. Bergmann-Wolf H. Dobslaw T. Gruber A. Güntner M. Wattenbach S. Esselborn R. Dill 《Surveys in Geophysics》2014,35(6):1251-1266
Reducing aliasing effects of insufficiently modelled high-frequent, non-tidal mass variations of the atmosphere, the oceans and the hydrosphere in gravity field models derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission is the topic of this study. The signal content of the daily GRACE gravity field model series (ITG-Kalman) is compared to high-frequency bottom pressure variability and terrestrially stored water variations obtained from recent numerical simulations from an ocean circulation model (OMCT) and two hydrological models (WaterGAP Global Hydrology Model, Land Surface Discharge Model). Our results show that daily estimates of ocean bottom pressure from the most recent OMCT simulations and the daily ITG-Kalman solutions are able to explain up to 40 % of extra-tropical sea-level variability in the Southern Ocean. In contrast to this, the daily ITG-Kalman series and simulated continental total water storage variability largely disagree at periods below 30 days. Therefore, as long as no adequate hydrological model will become available, the daily ITG-Kalman series can be regarded as a good initial proxy for high-frequency mass variations at a global scale. As a second result of this study, based on monthly solutions as well as daily observation residuals, it is shown that applying this GRACE-derived de-aliasing model supports the determination of the time-variable gravity field from GRACE data and the subsequent geophysical interpretation. This leads us to the recommendation that future satellite concepts for determining mass variations in the Earth system should be capable of observing higher frequeny signals with sufficient spatial resolution. 相似文献
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大同—阳高地震前后重力变化分析 总被引:1,自引:0,他引:1
汇总了1989年10月18日大同—阳高6.1级地震前4个单位所观测到的重力异常变化资料,在叙述重力异常的基础上,讨论分析了此次地震的重力前兆特征。并结合形变资料、地震构造资料讨论了重力场的变化,得出这些变化可能与地震构造活动有关的结论。 相似文献
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地震分析预报的重力变化异常指标分析 总被引:1,自引:2,他引:1
定义了描述地震前重力变化异常时变距和量级的参数S和G。根据收集到的89个4.0级以上地震震例,统计分析了震前重力变化异常范围和量级与震级的关系,得到了流动重力地震分析预报的量化参考指标。结果表明:5、6、7、8级地震震级判定的重力变化异常量级参考指标分别为50、70、90、120μGal,重力变化异常范围参考指标分别为140、220、350、660km。此外,由于流动重力观测周期等方面的局限性,根据流动重力观测资料尚难以获得震级与重力变化异常时间过程的关系。 相似文献
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--Models of combined Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data collected in the region of the Northridge earthquake indicate that significant afterslip on the main fault occurred following the earthquake. Additional shallow deformation occurred to the west of the main rupture plane. Both data sets are consistent with logarithmic time-dependent behavior following the earthquake indicative of afterslip rather than postseismic relaxation. Aftershocks account for only about 10% of the postseismic motion. The two data sets are complimentary in determining the postseismic processes. Fault afterslip and shallow deformation dominate the deformation field in the two years following the earthquake. Lower crustal deformation may play an important role later in the earthquake cycle. 相似文献
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小波分析是具有时频多分辨率分析特点的新的信号处理方法,本文应用时间序列反映出大地电磁信号功率谱特性并比较了几种常规实验手段的分析效果,通过小波变换分离出假频所在通道并进行初步除噪,按能量强弱对信号重新截断划分.本文的目的就是尽可能的消除对各组信号不一致的影响因素(局部噪声),提取共性较强的部分并按能量的差异来划分这些信号. 相似文献