A 70th degree lunar gravity model (GLGM‐2) from Clementine and other tracking data
A 70th degree lunar gravity model (GLGM‐2) from Clementine and other tracking data
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DOI：
10.1029/97je01418
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发表时间：
1997-07
影响因子：
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通讯作者：
F. LeMoine;David E. Smith;M. Zuber;G. Neumann;D. Rowlands
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文献类型：
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作者：
F. LeMoine;David E. Smith;M. Zuber;G. Neumann;D. Rowlands
根据克莱门汀使命的S波段多普勒跟踪数据以及月球轨道器1-5号和阿波罗15号和16号子卫星的历史跟踪数据，建立了一个完整的70阶月球重力场球谐模型。该模型结合了Clementine的361，000个多普勒观测值和347，000个历史观测值。历史数据主要由60秒的多普勒组成，噪声为0.25至几mm/s。克莱门汀数据主要由10秒多普勒数据组成，来自深空网络的观测数据噪声为0.25毫米/秒，来自马里兰州波蒙基的海军跟踪站的数据噪声为2.5毫米/秒。克莱门汀提供的观测结果提供了对月球低度场最强的卫星约束。相比之下，由具有较低近心点高度的航天器收集的历史数据提供了近月赤道±29°范围内的高分辨率分布区域。为了在观测值不均匀分布的情况下得到高阶场的解，我们应用了一个先验的幂律约束，其形式为15×10−5/l2，它可以限制短波长下的引力功率和噪声。通过度和阶数18的系数不受该约束的显著影响，因此该模型允许对10-12度的主要盆地的影响进行地球物理分析。GLGM-2模型证实了以前重力场模型中显示的月球重力场的主要特征，但也揭示了更多的细节，特别是在中间波长（103公里）。根据新模型得到的自由空间重力异常图显示，高地的近端和远端重力平滑，反映了均衡补偿的状态。Mascon盆地（包括Imperial、Serenitatis、Crisium、Smythii和Humorum）是由月球轨道器跟踪首次识别的重力高表示的。所有的主要质量体都被代表显著地下质量缺陷的负异常环所包围。东方海看起来像一个小质量体，周围环绕着一个马蹄形的重力低，中心位于内外鲁克环上，这是地下结构不均匀性的证据。虽然在月球背面的大部分地区无法进行直接跟踪，但GLGM-2解决了与许多背面盆地相关的负异常，包括南极-艾特肯，赫茨普龙，科罗廖夫，莫斯科维恩斯，齐奥尔科夫斯基和弗罗因德利希-沙罗诺夫。
A spherical harmonic model of the lunar gravity field complete to degree and order 70 has been developed from S band Doppler tracking data from the Clementine mission, as well as historical tracking data from Lunar Orbiters 1–5 and the Apollo 15 and 16 subsatellites. The model combines 361,000 Doppler observations from Clementine with 347,000 historical observations. The historical data consist of mostly 60-s Doppler with a noise of 0.25 to several mm/s. The Clementine data consist of mostly 10-s Doppler data, with a data noise of 0.25 mm/s for the observations from the Deep Space Network, and 2.5 mm/s for the data from a naval tracking station at Pomonkey, Maryland. Observations provided Clementine, provide the strongest satellite constraint on the Moon's low-degree field. In contrast the historical data, collected by spacecraft that had lower periapsis altitudes, provide distributed regions of high-resolution coverage within ±29° of the nearside lunar equator. To obtain the solution for a high-degree field in the absence of a uniform distribution of observations, we applied an a priori power law constraint of the form 15×10−5/l2 which had the effect of limiting the gravitational power and noise at short wavelengths. Coefficients through degree and order 18 are not significantly affected by the constraint, and so the model permits geophysical analysis of effects of the major basins at degrees 10–12. The GLGM-2 model confirms major features of the lunar gravity field shown in previous gravitational field models but also reveals significantly more detail, particularly at intermediate wavelengths (103 km). Free-air gravity anomaly maps derived from the new model show the nearside and farside highlands to be gravitationally smooth, reflecting a state of isostatic compensation. Mascon basins (including Imbrium, Serenitatis, Crisium, Smythii, and Humorum) are denoted by gravity highs first recognized from Lunar Orbiter tracking. All of the major mascons are bounded by annuli of negative anomalies representing significant subsurface mass deficiencies. Mare Orientale appears as a minor mascon surrounded by a horseshoe-shaped gravity low centered on the Inner and Outer Rook rings that is evidence of significant subsurface structural heterogeneity. Although direct tracking is not available over a significant part of the lunar farside, GLGM-2 resolves negative anomalies that correlate with many farside basins, including South Pole-Aitken, Hertzsprung, Korolev, Moscoviense, Tsiolkovsky, and Freundlich-Sharonov.