Venus Gravity: 180th Degree and Order Model
Venus Gravity: 180th Degree and Order Model
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DOI：
10.1006/icar.1999.6086
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发表时间：
1999-05
期刊：
影响因子：
3.2
通讯作者：
A. Konopliv;W. Banerdt;W. Sjogren
中科院分区：
文献类型：
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作者：
A. Konopliv;W. Banerdt;W. Sjogren
麦哲伦多普勒辐射跟踪数据为航天器重力测量提供了前所未有的精度，在选定的赤道地区，其最大分辨率接近球谐度和180阶。即使在我们使用的JPL/Caltech超级计算机上，用包含所有球面谐波系数（三角形矩阵的4.5 gb二进制文件）之间的相关性的完整协方差来确定180度的重力场也将是一项广泛的计算任务。相反，我们确定了一个完整的180度和阶重力场，但在三个不同的步骤。这个重力解（MGNP180U）首先被确定为120度和120阶，所有系数都是120度的完整协方差。第二步只求116到155度的系数第三步求154到180度的系数。MGNP180U比以前的解决方案（包括MGNP120PSAAP， a.s. Konoplivet .1996a， 1996 AGU秋季会议，San Francisco， CA）有了实质性的改进，特别是在中短波长（谐波度80及更高）。光谱中的均方根值功率有所增加，与地形的相关性也有所增加。各种特征的振幅大幅增加（高达33%，例如贝尔地区和Maat Mons）。这将有助于更好地研究较短波长的岩石圈模型，如日冕、火山和撞击盆地。
The Magellan Doppler radiometric tracking data provides unprecedented precision for spacecraft-based gravity measurements with the maximum resolution approaching spherical harmonic degree and order 180 in selected equatorial regions. Determining a gravity field to degree 180 with a complete covariance containing the correlations between all the spherical harmonic coefficients (a 4.5-GB binary file for the triangular matrix) would be an extensive computational task even on the JPL/Caltech supercomputer that we used. Instead we determined a gravity field complete to degree and order 180 but in three separate steps. This gravity solution (MGNP180U) was determined first to degree and order 120 with a complete covariance for all the coefficients to degree 120. The second step solved for the coefficients from degree 116 to 155 only and the third step from degree 154 to 180. MGNP180U shows substantial improvement over previous solutions (up to and including MGNP120PSAAP, A. S. Konoplivet al.1996a, presented at1996 AGU Fall Meeting,San Francisco, CA) especially in the medium to shorter wavelengths (harmonic degree 80 and greater). The RMS magnitude power in the spectrum has increased as well as the correlations with topography. The amplitudes of various features have increased substantially (up to 33%, e.g., Bell Regio and Maat Mons). This will allow for better investigation of lithospheric modeling for shorter wavelength features such as coronae, volcanoes, and impact basins.