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利用3台LaCoste-Romberg型弹簧重力仪（G-589、ET-20和ET-21）在南极中山站和长城站的长期重力潮汐观测资料，在武汉国际重力潮汐基准上精密测定了中山站和长城站的重力潮汐参数，其中主波振幅因子的标准偏差优于0.5％．各潮波的观测振幅在中山站比在长城站的小得多，两站周日潮（O1）的观测振幅因子相差约7％，而半日潮（M2）的观测振幅因子相差超过40％，气压和温度等气象因素的变化对观测结果的影响很明显．海潮负荷对两台站潮汐观测的影响非常显著，采用Schwiderski全球海潮模型对观测结果作海潮负荷重力改正．结果表明，经海潮改正后，各潮波的观测残差有较大幅度的减小，但是，由于采用的海潮模型没有顾及台站近区的海潮负荷效应，所以，O1 波的振幅因子对相应理论潮汐模型值之间存在大约4％（中山站）和9％（长城站）的偏差． 相似文献
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采用固体潮理论模型值和由最新的TPXO7海潮模型以及中国近海潮汐资料计算的海潮负荷效应，构制了中国及邻区的高分辨率的重力合成潮汐参数；并将合成结果与国家地震台网的重力观测值和武汉超导重力仪观测值以及香港台最新观测结果进行了比较. 结果表明，振幅因子的平均差异小于0.005，相位差的平均差异小于0.5deg;；观测结果与合成结果之间的差异与重力观测仪器有关，高精度的超导重力仪观测结果与合成参数更加一致；重力合成潮汐参数是观测值很好的模拟. 本文结果可为绝对重力测量等地表和空间大地测量提供固体潮改正模型，也可为没有实施观测的广大区域提供有效潮汐参数. 相似文献
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本文在计算海潮对重力固体潮观测的影响时,把全球海域分成近区和远区两部分。其中近区采用格林函数数值积分法,在远区对g~N(日)采用卷积积分法,而对g~E(日)利用函数级数拟合全球海潮潮高的球函数展开法。最后计算了北京、兰州和拉萨的重力固体潮观测值的海潮改正。 相似文献
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为了检验体潮与海潮的理论模型,分析了中国东西重力潮汐剖面（1981年9月-1985年1月）。同时,为研究LaCoste ET-20和ET-21重力仪的格值系统,建立了一条由17台LaCoste G型和2台LaCoste D型重力仪观测的重力垂直基线。在基线上标定的结果表明,ET-21重力仪的格值大了1％。由标定得到的格值计算剖面上各测站的潮汐因子,经海潮改正后,接近Wahr模型值,振幅因子的残差:O1波小于0.3μGal,M2波小于0.4μGal。但是上海和拉萨的观测经海潮改正后,相位迟后有很大的改善,振幅因子却更偏离于模型值,其潮汐异常主要是近海的海潮模型不完善,以及在海潮计算中,所采用的地球模型未考虑地壳与上地幔的横向不均匀性所引起。 相似文献
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采用武汉台超导重力仪(SG C032)14年多的长期连续观测资料,研究了固体地球对二阶和三阶引潮力的响应特征,精密测定了重力潮汐参数,系统研究了最新的固体潮模型和海潮模型在中国大陆的有效性.采用最新的8个全球海潮模型计算了海潮负荷效应,从武汉台SG C032的观测中成功分离出63个2阶潮汐波群和15个3阶潮汐波群信号,3阶潮波涵盖了周日、半日和1/3日三个频段.重力潮汐观测的精度非常高,标准偏差达到1.116 nm·s-2,系统反映了非流体静力平衡、非弹性地球对2阶和3阶引潮力的响应特征.结果表明,现有的武汉国际重力潮汐基准在半日频段非常精确,但在周日频段存在比较明显的偏差,需要进一步精化.对于中国大陆的大地测量观测,固体潮可以采用Dehant等考虑地球内部介质非弹性和非流体静力平衡建立的固体潮理论模型或Xu 等基于全球SG观测建立的重力潮汐全球实验模型作为参考和改正模型,海潮负荷效应应该采用Nao99作为改正模型. 相似文献
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本文讨论了海潮对卫星重力测量的影响问题. 首先介绍了海潮对卫星重力测量影响的基本理论；采用FES02和TPXO6海潮模型计算了海潮负荷对卫星重力结果前60阶的影响；并用两个模型之间的差异作为海潮模型精度的估计量，据此计算了海潮模型误差对卫星重力结果的影响. 与GRACE恢复的重力场精度的比较说明：海潮对重力场40阶以下的影响都超过了目前重力场恢复精度；尽管由于卫星测高技术的发展，海潮模型的精度有了很大的提高，但目前的全球海潮模型用于GRACE重力场恢复的前12阶的改正还是不够精确. 另外，我们也利用中国东海和南海潮汐资料以及FES02海潮模型讨论了中国近海潮汐效应对GRACE观测的影响. 结果说明该影响与海潮模型的误差相当. 这反映了当前海潮模型的不确定度，因此通过结合全球验潮站资料有望提高海潮对卫星重力测量的改正精度. 相似文献
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利用理论和实验重力固体潮模型,充分考虑全球海潮和中国近海潮汐的负荷效应,建立了中国大陆的精密重力潮汐改正模型.结果表明,采用不同的固体潮模型会对重力潮汐结果产生相对变化幅度小于0.06％的差异;在沿海地区海潮负荷的影响约为整个潮汐的4％,而中部地区约为1％,其中中国近海潮汐模型的影响约占整个海潮负荷的10%,内插或外推潮波的负荷约占海潮负荷的3％.通过比较实测的重力数据表明,本文给出的重力潮汐改正模型的精度远远优于0.5×10-8 m·s-2,说明了本文构建的模型的实用性,可为中国大陆高精度重力测量提供有效参考和精密的改正模型. 相似文献
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为了研究海潮与固体潮的相互作用,对近海的泉州台用三台重力仪（二台LaGoste-G型、一台GS型）为期四个半月的观测资料进行了初步分析,探讨了仪器的性能及误差来源。由分析得出: 1.由LaCoste-G型584和589重力仪观测得到的结果是一致的,三台仪器对于主要潮波O1和M2波的观测结果也相符较好,其互差不超过8‰。利用Schwiderski图和我国等潮图作海潮改正后的潮汐因子接近理论模型值。但由于泉州为近海台,大的余差可能反映了局部地区海潮的影响。 2.LaCoste-G型重力仪的误差主要来自灵敏度的变化,应在基本台上作定期标定。 3.GS-207重力仪的观测结果受气压的影响较大,特别是K1和S2波,经初步分析得出约7微伽/毫巴。 相似文献
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Temporal variations in free core nutation period 总被引：1，自引：0，他引：1
Based on the nearly diurnal resonance in the tidal gravity observations,the temporal variations in period of the Earth's free core nutation (FCN) are investigated by using the tidal gravity observations of 18-year duration recorded continu-ously with a superconducting gravimeter (SG) at Brussels. The effects of the global oceanic tide loading and local barometric pressure on the SG observations have been removed by using eleven high-precision global digital models of oceanic tides and barometric pressure me... 相似文献
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综述了近年内在全球地球动力学合作观测和研究网络框架下开展的重力场观测、频谱结构和应用研究方面的成果. 内容涉及精密大气、海潮负荷信号检测, 重力潮汐和自由核章动参数测定, 海潮模型和重力固体潮模型有效性检验, 重力潮汐实验模型构制, 地球球型基频和低阶震型谱峰分裂现象和地球Chandler摆动等方面. 文章还介绍了综合现代大地测量技术, 全球超导重力仪的长期、连续观测在地表水循环、同震和震后形变、地球慢形变和地壳垂直运动等方面将发挥重要作用的情况. 相似文献
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海潮误差是GRACE时变重力场反演中重要的误差源,目前发布的海潮模型中主要包含振幅较大的主潮波分量模型,在时变重力场反演中次潮波的影响也是不可忽略的,因此,GRACE时变重力场反演中的海潮误差主要包括受限于海潮模型误差和次潮波影响.本文利用轨道模拟方法检测了短周期潮波的混频周期以及次潮波对ΔC20,ΔC30的时序特征,并进一步通过轨道模拟结果分析了海潮误差对时变重力场反演的影响,然后通过实测数据解算分析了海潮误差对当前GRACE时变重力场解算的影响,研究发现:(1)利用轨道模拟能够有效地检测短周期潮波的混频周期;(2)时变重力场解算过程中,次潮波的影响大于海潮模型误差的影响;(3)海潮模型误差以及次潮波影响是当前GRACE没有达到基准精度的重要因素之一. 相似文献
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P. Melchior M. Moens B. Ducarme M. Van Ruymbeke 《Physics of the Earth and Planetary Interiors》1981,25(1):71-106
A knowledge of the vertical component of the oceanic tidal load to a precision of at least one microgal is essential for the geophysical exploitation of the high-precision absolute and differential gravity measurements which are being made at ground level and in deep boreholes. On the other hand the ocean load and attraction signal contained in Earth tide gravity measurements can be extracted with a precision which is sufficient to characterize the behaviour of the oceanic tides in different basins and this provides a check of the validity of the presently proposed cotidal maps. The tidal gravity profiles made since 1971 from Europe to Polynesia, through East Africa, Asia and Australia, with correctly intercalibrated gravimeters, comprise information from 91 tidal gravity stations which is used in this paper with this goal in mind.A discussion of all possible sources of error is presented which shows that at the level of 0.5 μgal the observed effects cannot be ascribed to computational or instrumental errors. Cotidal maps which generate computed loads in agreement with the Earth tide gravity measurements over a sufficiently broad area can be used with confidence as a working standard to apply tidal corrections to high-precision measurements made by using new techniques in geodesy, geophysics and geodynamics, satellite altimetry, very long baseline interferometry, Moon and satellite laser ranging and absolute gravity. The recent cotidal maps calculated by Schwiderski for satellite altimetry reductions agree very well with land-based gravimeter observations of the diurnal components of the tides (O1, K1 and P1 waves) but his semi-diurnal component maps (M2, S2 and N2 waves) strangely appear less satisfactory in some large areas. The maps of Hendershott and Parke give good results in several large areas but not everywhere. More detailed investigations are needed not only for several coastal stations but mainly in the Himalayas. 相似文献
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《Journal of Geodynamics》2010,49(3-5):354-359
In order to achieve a consistent combination of terrestrial and satellite-derived (GRACE) gravity field variations reductions of systematic perturbations must be applied to both data sets. At the same time evidence needs to be provided that these reductions are both necessary and sufficient. Based on the OMCT and the ECCO model the gravity effect of non-tidal oceanic mass shifts is computed for various sites equipped with a superconducting gravimeter (SG) and esp. the long-periodic contributions are studied. With these oceanic models the dynamic ocean response to atmospheric pressure loading is automatically computed, and thus goes beyond the more simplistic concepts of an inverted barometer, or alternately a rigid ocean, which is a clear advantage.The findings so far are ambiguous: for instance the systematic seasonal change of about 10 nm/s2 in gravity for mid-European stations is presently not found in the observed gravity variations. Generally, the order of magnitude of the total effect of 22–27 nm/s2 is surprisingly large for inland stations. In some data sections the reduction leads to the removal of some of the larger residuals. The results obtained for the South-African station Sutherland differ. Here the modelled seasonal variation caused by the non-tidal oceanic mass redistribution and gravity residuals generally correlate, and thus by the reduction an improvement of the signal-to-noise ratio in the gravity observations is achieved.An explanation for the different results might be found in the global hydrological models. Such a model is needed in order to remove the effect of large-scale variations in continental water storage in the gravity observations. This reduction plays a greater role for European stations than for the South African site. A critical impact of the land-sea-mask used in the oceanic models and the subsequent insufficient resolution of the North and Baltic Sea on the computations at the mid-European sites could not be confirmed.From a comparison between the OMCT and the ECCO model substantial discrepancies in some regions of the earth emerge, while both predict variations at inland stations in Europe, South Africa, and Asia of similar magnitude. We currently hesitate to recommend including this reduction in the routine processing of SG data because the seasonal order of magnitude for inland stations is unexpectedly large and partly significant deviations between the modelled oceanic effects exist. If the order of magnitude proves to be correct universally, this reduction has to be applied. 相似文献