The static gravity field model DGM-1S from GRACE and GOCE data: computation, validation and an analysis of GOCE mission’s added value
The static gravity field model DGM-1S from GRACE and GOCE data: computation, validation and an analysis of GOCE mission’s added value
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DOI：
10.1007/s00190-013-0650-3
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发表时间：
2013-07
影响因子：
4.4
通讯作者：
H. Farahani;P. Ditmar;R. Klees;X. Liu;Q. Zhao;J. Guo
中科院分区：
文献类型：
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作者：
H. Farahani;P. Ditmar;R. Klees;X. Liu;Q. Zhao;J. Guo
基于GRACE和GOCE数据建立了一个全球静态地球重力场模型DGM-1 S。所使用的数据集包括近7年的GRACE KBR数据和10个月的GOCE重力梯度数据。KBR数据通过3点微分转换为近似为卫星间加速度的量。重力梯度是在仪器框架中处理的。噪声处理与频率相关的数据加权。DGM-1 S完成球谐次数250，并在次数179以上应用Kaula正则化。它的性能进行了比较，与其他一些只有卫星的GRACE/GOCE模式，面对他们与（一）一个独立的海洋平均动态地形模型，和（二）独立的KBR和重力梯度数据。测试表明DGM-1 S具有竞争力的质量。重要的是，我们通过比较仅卫星GRACE/GOCE模型与没有GOCE数据的模型的性能来研究GOCE数据的附加值：ITG-Grace 2010 s或EGM 2008，这取决于两者中哪一个在给定区域中表现更好。基于独立重力梯度执行的测试将这一附加值量化为25- 38%，在陆地重力测量数据覆盖较差的大陆地区（赤道非洲，喜马拉雅山和南美洲），7- 17%，在这些数据覆盖良好的地区（澳大利亚，北美和欧亚大陆北部），以及14%的海洋。这个附加值几乎完全与200度以下的系数有关。结果表明，这种增益必须完全归因于重力梯度获得的使命。基于一个独立的平均动态地形模型进行的测试表明，问题似乎仍然存在于太平洋上空的卫星GRACE/GOCE模型，这些模型和EGM 2008之间的显着偏差检测，太。
We present a global static model of the Earth’s gravity field entitled DGM-1S based on GRACE and GOCE data. The collection of used data sets includes nearly 7 years of GRACE KBR data and 10 months of GOCE gravity gradient data. The KBR data are transformed with a 3-point differentiation into quantities that are approximately inter-satellite accelerations. Gravity gradients are processed in the instrumental frame. Noise is handled with a frequency-dependent data weighting. DGM-1S is complete to spherical harmonic degree 250 with a Kaula regularization being applied above degree 179. Its performance is compared with a number of other satellite-only GRACE/GOCE models by confronting them with (i) an independent model of the oceanic mean dynamic topography, and (ii) independent KBR and gravity gradient data. The tests reveal a competitive quality for DGM-1S. Importantly, we study added value of GOCE data by comparing the performance of satellite-only GRACE/GOCE models with models produced without GOCE data: either ITG-Grace2010s or EGM2008 depending on which of the two performs better in a given region. The test executed based on independent gravity gradients quantifies this added value as 25–38 % in the continental areas poorly covered with terrestrial gravimetry data (Equatorial Africa, Himalayas, and South America), 7–17 % in those with a good coverage with these data (Australia, North America, and North Eurasia), and 14 % in the oceans. This added value is shown to be almost entirely related to coefficients below degree 200. It is shown that this gain must be entirely attributed to gravity gradients acquired by the mission. The test executed based on an independent model of the mean dynamic topography suggests that problems still seem to exist in satellite-only GRACE/GOCE models over the Pacific ocean, where noticeable deviations between these models and EGM2008 are detected, too.