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1.
高精度重力场模型精化Kaula规则其要点是将Kaula规则乘上一个与位系数阶数项相关的二阶有理函数,并基于EIGEN6C2重力场模型解算有理函数模型的系数。精化后的Kaula规则与EIGEN6C2模型和EGM2008模型的逼近误差都只是原来Kaula规则的0.26%。因此,精化后的Kaula规则更能正确表示各阶引力位的实际能量,对于重力场模型的解算提供更加合理的约束。  相似文献   

2.
High-resolution satellite gravity data of gravity recovery and climate experiment (GRACE) generated by Earth Gravity Model-2008 (EGM2008) have been utilised for geological mapping of the Jharia coalfield. The generated GRACE EGM2008 classical gravity data have been processed for estimation of gravity anomaly map. The gravity anomaly map has been enhanced using the first and second Vertical Derivatives techniques. Geological and structural maps of the study area have been overlapped over different derivative maps to analyse the correlation with the subsurface geological structures of the study area. Major distinct geological signatures, on different derivative maps, are correlated well with the existing geological map. Moreover, vertical derivative maps of the gravity data generated from GRACE EGM2008 model provide better agreement and understanding for geological setting of the Jharia coalfield.  相似文献   

3.
基于能量守恒方法恢复CHAMP重力场模型   总被引：3，自引：0，他引：3  
介绍了基于能量守恒定律恢复地球重力场模型的基本原理和算法.指出了CHAMP加速度计数据存在的问题,提出了整体求解尺度因子、偏差参数和偏差漂移的数学模型及差分算法.利用2002年1月的CHAMP快速科学轨道数据和加速度计数据计算出了50 × 50地球重力场模型XISM02.将该模型与EGM96,GRIM5C1,EIGEN1S,EIGEN2模型进行了比较,并用北极实测重力数据对上述模型进行了检验.结果表明:XISM02模型在北极地区精度与EIGEN1S,EIGEN2相当.  相似文献   

4.
The present study deals with classical problem of edge detection in potential field data over complex tectonic regime for both shallower and deeper sources, simultaneously. Balanced horizontal derivative (BHD) technique is a latest edge detection concept which delineates edges using balancing of amplitude responses for both shallower and deeper sources. The BHD technique has been validated by comparing with total horizontal derivative (THD) technique. Initially, three different synthetic models have been generated with spherical, cylindrical and vertical prismatic objects at different depths and corresponding gravity responses have been enhanced using BHD and THD techniques. Structural features have been delineated from EIGEN6C4 free-air gravity data using THD and BHD techniques over a part of the Bay of Bengal. Major lineaments have been identified in N–S direction followed by those identified along the NE–SW, NW–SE and E–W directions. Both studies of synthetic models and real gravity data reveal that BHD is an advanced technique than THD.  相似文献   

5.
The earth gravity field model CDS01S of degree and order 36 has been recovered from the post processed Science Orbits and on-board accelerometer data of GFZ's CHAMP satellite. The model resolves the geoid with an accuracy of better than 4 cm at a resolution of 700 km half-wavelength. By using the degree difference variances of geopotential coefficients to compare the model CDS01S with EIGEN3P, EIGEN1S and EGM96, the result indicates that the coefficients of CDS01S are most close to those of EIGEN3P. The result of the comparison between the accuracies of geopotential coefficients in the above models, indicates that the accuracy of coefficients in CDS01S is higher than that in EGM96. The geoid undulations of CDS01S and GGM01C up to 30 degrees are calculated and the standard deviation is 4. 7 cm between them.  相似文献   

6.
The availability of high-resolution global digital elevation data sets has raised a growing interest in the feasibility of obtaining their spherical harmonic representation at matching resolution, and from there in the modelling of induced gravity perturbations. We have therefore estimated spherical Bouguer and Airy isostatic anomalies whose spherical harmonic models are derived from the Earth’s topography harmonic expansion. These spherical anomalies differ from the classical planar ones and may be used in the context of new applications. We succeeded in meeting a number of challenges to build spherical harmonic models with no theoretical limitation on the resolution. A specific algorithm was developed to enable the computation of associated Legendre functions to any degree and order. It was successfully tested up to degree 32,400. All analyses and syntheses were performed, in 64 bits arithmetic and with semi-empirical control of the significant terms to prevent from calculus underflows and overflows, according to IEEE limitations, also in preserving the speed of a specific regular grid processing scheme. Finally, the continuation from the reference ellipsoid’s surface to the Earth’s surface was performed by high-order Taylor expansion with all grids of required partial derivatives being computed in parallel. The main application was the production of a 1′ × 1′ equiangular global Bouguer anomaly grid which was computed by spherical harmonic analysis of the Earth’s topography–bathymetry ETOPO1 data set up to degree and order 10,800, taking into account the precise boundaries and densities of major lakes and inner seas, with their own altitude, polar caps with bedrock information, and land areas below sea level. The harmonic coefficients for each entity were derived by analyzing the corresponding ETOPO1 part, and free surface data when required, at one arc minute resolution. The following approximations were made: the land, ocean and ice cap gravity spherical harmonic coefficients were computed up to the third degree of the altitude, and the harmonics of the other, smaller parts up to the second degree. Their sum constitutes what we call ETOPG1, the Earth’s TOPography derived Gravity model at 1′ resolution (half-wavelength). The EGM2008 gravity field model and ETOPG1 were then used to rigorously compute 1′ × 1′ point values of surface gravity anomalies and disturbances, respectively, worldwide, at the real Earth’s surface, i.e. at the lower limit of the atmosphere. The disturbance grid is the most interesting product of this study and can be used in various contexts. The surface gravity anomaly grid is an accurate product associated with EGM2008 and ETOPO1, but its gravity information contents are those of EGM2008. Our method was validated by comparison with a direct numerical integration approach applied to a test area in Morocco–South of Spain (Kuhn, private communication 2011) and the agreement was satisfactory. Finally isostatic corrections according to the Airy model, but in spherical geometry, with harmonic coefficients derived from the sets of the ETOPO1 different parts, were computed with a uniform depth of compensation of 30?km. The new world Bouguer and isostatic gravity maps and grids here produced will be made available through the Commission for the Geological Map of the World. Since gravity values are those of the EGM2008 model, geophysical interpretation from these products should not be done for spatial scales below 5 arc minutes (half-wavelength).  相似文献   

7.
IntroductionSince the launch of man-made satellite early in1957 ,the research for satellite gravity has beentaken a wide attentioninfield of geodesy .Early ,the ground-based satellite tracking has providedan observational data set which has been used tode…  相似文献   

8.
We describe the computation of the first Australian quasigeoid model to include error estimates as a function of location that have been propagated from uncertainties in the EGM2008 global model, land and altimeter-derived gravity anomalies and terrain corrections. The model has been extended to include Australia’s offshore territories and maritime boundaries using newer datasets comprising an additional \({\sim }\)280,000 land gravity observations, a newer altimeter-derived marine gravity anomaly grid, and terrain corrections at \(1^{\prime \prime }\times 1^{\prime \prime }\) resolution. The error propagation uses a remove–restore approach, where the EGM2008 quasigeoid and gravity anomaly error grids are augmented by errors propagated through a modified Stokes integral from the errors in the altimeter gravity anomalies, land gravity observations and terrain corrections. The gravimetric quasigeoid errors (one sigma) are 50–60 mm across most of the Australian landmass, increasing to \({\sim }100\) mm in regions of steep horizontal gravity gradients or the mountains, and are commensurate with external estimates.  相似文献   

9.
基于卫星动力学理论,采用德国地球科学中心GFZ提供的CHAMP精密轨道数据和星载加速度计数据,反演了36阶地球重力场模型CDS01S。用不同模型之间的位系数差比较模型CDS01S、EIGEN3P、EIGEN1S及EGM96,表明CDS01S模型的位系数最接近于EIGEN3P;比较上述几种模型的位系数精度,表明CDS01S模型的位系数精度高于EGM96;用CDS01S和GGM01C的前30阶位系数分别计算全球2°×2°网格的大地水准面起伏,两者之间的标准偏差为4.7 cm。  相似文献   

10.
本文研究了联合卫星观测数据和重力异常数据确定超高阶重力场模型的理论方法,并使用EGM2008模型重力异常和GOCE（gravity field and ocean circulation explorer）观测数据构建了重力场模型SGG-UGM-1。重点研究了由球面格网重力异常快速构建超高阶重力场模型的块对角最小二乘方法,将OpenMP技术引入到块对角最小二乘中以提高计算效率,并基于模拟数据验证了方法及算法和软件模块的正确性。采用本文制定的联合解算策略,利用GOCE重力卫星观测数据构建的220阶次法方程和EGM2008模型重力异常构建的2159阶次块对角法方程,联合求解了2159阶次的重力场模型SGG-UGM-1。将SGG-UGM-1与EGM2008、EIGEN-6C2、EIGEN-6C4等超高阶模型在频谱域内进行了比较分析,结果表明SGG-UGM-1相对参考模型的系数误差较小,且在220阶次内的系数精度相比EGM2008模型有了提高。采用中国与美国的GPS/水准数据和毛乌素测区的航空重力观测数据对这些模型进行了外符合精度的检验。检核结果表明,在中国区域,SGG-UGM-1模型大地水准面的精度在EIGEN-6C2和EIGEN-6C4两个模型之间,优于GOSG-EGM模型和EGM2008模型,与美国区域几个模型的精度相当。利用毛乌素测区的航空重力数据对几个模型进行了检核,结果表明SGG-UGM-1模型计算的重力扰动精度与EGM2008、EIGEN-6C4模型相当,优于GOSG-EGM模型和EIGEN-6C2模型。  相似文献   

11.
针对局部重力异常向上延拓计算复杂、耗时长的问题,该文基于泊松积分离散化的基本原理,提出一种快速的局部格网重力异常向上延拓的实用算法;并结合中国东北和青藏高原地区大地水准面的重力异常格网数据,采用该延拓方法分别计算了空中10、50、100km处的重力异常,将其与等高度的EIGEN-6C4模型结果对比分析。实验结果表明:在顾及边界效应影响的情况下,相对于EIGEN-6C4模型,中国东北和青藏高原地区重力异常向上延拓的最大均方根误差分别优于1.5和3.5mGal;在保证精度可用的前提下,计算效率可以有大幅度提高,证明了该方法解算局部重力异常向上延拓的适用性。  相似文献   

12.
An efficient method for gravity field determination from CHAMP orbits and accelerometer data is referred to as the energy balance approach. A new CHAMP gravity field recovery strategy based on the improved energy balance approach IS developed in this paper. The method simultaneously solves the spherical harmonic coefficients, daily Integration constant, scale and bias parameters. Two 60 degree and order gravitational potential models, XISM-CHAMPO1S from the classical energy balance approach, and XISM-CHAMPO2S from the improved energy balance, are determined using about one year＇s worth of CHAMP kinematic orbits from TUM and accelerometer data from GFZ. Comparisons among XISM-CHAMPO1S, XISM-CHAMPO2S, EIGEN-CGO3C, EIGEN-CHAMPO3S, EIGEN2, ENIGNIS and EGM96 are made. The results show that the XISM-CHAMPO2S model is more accurate than EGM96, EIGENIS, EIGEN2 and XISM-CHAMPO1S at the same degree and order, and has almost the same accuracy as EIGEN-CHAMPO3S.  相似文献   

13.
提出了一种基于大地水准面等位面特性的地球重力场模型优劣评价方法。通过取任一重力大地水准面为参考面,计算不同地球重力场模型在该面上的重力位标准差,以此作为不同模型相对优劣的评价指标。利用该方法对不同地球重力场模型以及同一重力场模型在不同区域的精度进行了评价。结果表明:EGM96、OSU91A模型的大地水准面高精度分别为±11.1 cm、±14.3 cm,说明EGM96要优于OSU91A,EGM2008、EIGEN-6C4模型的大地水准面高精度分别为±8.8 cm、±8.9 cm,说明该两个模型的精度相当,与已有研究结果一致,表明本文方法的有效性与适用性。进一步研究结果显示,对于全球大地水准面,EGM2008和EIGEN-6C4模型的大地水准面高精度分别为±11.3 cm和±14.1 cm,即在厘米级精度上EGM2008略优。  相似文献   

14.
基于德国慕尼黑技术大学(TUM)提供的100 d的CHAMP卫星几何法轨道和GFZ提供的加速度计数据,计算出了50×50阶地球重力场模型XISM-CHAMP01,并与EIGEN-CG03C、EIGEN-CHAMP03S、EIGEN2、EIGEN1S、EGM96模型进行了比较。结果表明,XISM-CHAMP01模型精度明显优于相同阶次EGM96模型和EIGEN1S模型,并与EIGEN2模型精度相当。  相似文献   

15.
Gravimetric quantities are commonly represented in terms of high degree surface or solid spherical harmonics. After EGM2008, such expansions routinely extend to spherical harmonic degree 2190, which makes the computation of gravimetric quantities at a large number of arbitrarily scattered points in space using harmonic synthesis, a very computationally demanding process. We present here the development of an algorithm and its associated software for the efficient and precise evaluation of gravimetric quantities, represented in high degree solid spherical harmonics, at arbitrarily scattered points in the space exterior to the surface of the Earth. The new algorithm is based on representation of the quantities of interest in solid ellipsoidal harmonics and application of the tensor product trigonometric needlets. A FORTRAN implementation of this algorithm has been developed and extensively tested. The capabilities of the code are demonstrated using as examples the disturbing potential T, height anomaly \(\zeta \), gravity anomaly \(\Delta g\), gravity disturbance \(\delta g\), north–south deflection of the vertical \(\xi \), east–west deflection of the vertical \(\eta \), and the second radial derivative \(T_{rr}\) of the disturbing potential. After a pre-computational step that takes between 1 and 2 h per quantity, the current version of the software is capable of computing on a standard PC each of these quantities in the range from the surface of the Earth up to 544 km above that surface at speeds between 20,000 and 40,000 point evaluations per second, depending on the gravimetric quantity being evaluated, while the relative error does not exceed \(10^{-6}\) and the memory (RAM) use is 9.3 GB.  相似文献   

16.
断裂构造研究是重力解释的一项重要工作,与构造单元划分密切相关。全张量重力梯度数据以其信息量大、含有更高频的信号成分,能更好地描述小的异常特征等优点在地球物理领域中得到广泛应用。基于全张量重力梯度组合研究中国南海断裂识别及提取方法。首先,比较多种重力梯度边界识别方法,包括直接利用重力梯度三分量法和全张量梯度组合法,分析它们的优缺点。通过对比分析,传统重力梯度三分量方法不能有效地均衡深浅异常的振幅,当异常中同时出现正负异常可能产生假的边界结果。全张量重力梯度组合法不仅可以有效地避免传统方法的缺陷,而且获得的边界还具有良好的连续性和收敛性。其次,利用改进的边缘检测计算理论边界提取法确定断裂的精确平面位置,得到了与全张量梯度组合法一致的结果。由此推断,南海断裂以北东走向和北西走向为主,北东东、北西、东西和近南北走向为辅。  相似文献   

17.
将由大地高和正常高导出的几何高程异常与由位系数模型计算得到的物理高程异常进行比较,求出1985国家高程基准与全球似大地水准面之间的系统差,并分析其分布特性.为抵制异常值的影响,引入"抗差等价权".利用分布全国大陆范围的GPS网949个点的GPS/水准数据和地球重力场模型EGM96、DQM99A,求出1985国家高程基准点与WGS84定义的似大地水准面之间有35.7 cm的垂直偏差,1985国家高程基准面的系统差自东向西、自南向北明显增大,给出相应的数学模型.  相似文献   

18.
A global geopotential model, like EGM2008, is not capable of representing the high-frequency components of Earth’s gravity field. This is known as the omission error. In mountainous terrain, omission errors in EGM2008, even when expanded to degree 2,190, may reach amplitudes of 10 cm and more for height anomalies. The present paper proposes the utilisation of high-resolution residual terrain model (RTM) data for computing estimates of the omission error in rugged terrain. RTM elevations may be constructed as the difference between the SRTM (Shuttle Radar Topography Mission) elevation model and the DTM2006.0 spherical harmonic topographic expansion. Numerical tests, carried out in the German Alps with a precise gravimetric quasigeoid model (GCG05) and GPS/levelling data as references, demonstrate that RTM-based omission error estimates improve EGM2008 height anomaly differences by 10 cm in many cases. The comparisons of EGM2008-only height anomalies and the GCG05 model showed 3.7 cm standard deviation after a bias-fit. Applying RTM omission error estimates to EGM2008 reduces the standard deviation to 1.9 cm which equates to a significant improvement rate of 47%. Using GPS/levelling data strongly corroborates these findings with an improvement rate of 49%. The proposed RTM approach may be of practical value to improve quasigeoid determination in mountainous areas without sufficient regional gravity data coverage, e.g., in parts of Asia, South America or Africa. As a further application, RTM omission error estimates will allow refined validation of global gravity field models like EGM2008 from GPS/levelling data.  相似文献   

19.
利用GAMIT10.4和BERNESE5.2软件,分别对川滇地区中国地壳运动观测网络51个GNSS基准站2010—2014年的观测数据进行处理。两者解算所得单日解基线和坐标时间序列离散度优于10mm,且变化趋势一致,吻合度较高。基线重复率水平向优于1+4×10-9 L;垂向优于4+6×10-9 L(单位mm,其中L表示基线长度,单位m)。利用PL+VW噪声模型进行了速度估计,获取了川滇地区相对欧亚板块地壳运动速度场。结果显示:除滇西南地区呈现出由西向东的增大趋势外,川滇块体其它区域地壳运动特征由北往南、由西往东呈逐渐衰减趋势;运动方向持续围绕喜马拉雅东结点作顺时针旋转,且仍然存在着南北向强烈的挤压特征。以安宁河-则木河断裂、小江断裂和红河断裂为界,选用了两侧能反映震间断裂构造特征的GPS测站,分析了断裂两侧的速度差异。并利用平行断层的速度剖面,拟合反正切函数变化趋势,获取了断裂带可能的变形宽度。  相似文献   

20.
首先利用重力归算原理推导高程变化对重力观测值的影响，计算因高程变化导致重力布格异常改正、空间改正和层间改正。然后利用昆明市多年的InSAR影像资料，计算城区地面沉降变化量，在重力数据处理过程中结合InSAR技术得到地表沉降变化量，以及因地质密度变化引起的精确的重力值，进而计算得到该部分变化对昆明地区重力异常的影响情况。本文结合重力异常在地震方面的应用，说明提高重力测量精度在地质灾害中的意义。  相似文献   

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