Gravity field determination and characteristics: Retrospective and prospective

作者：R. S. Nerem, Christopher Jekeli, W. M. Kaula · 发表于：Journal of Geophysical Research Atmospheres · 年份：1995 · DOI：10.1029/94jb03257 · 被引用次数：71 · 研究领域：Geophysics and Gravity Measurements、Geomagnetism and Paleomagnetism Studies、Geophysical and Geoelectrical Methods

Gravimetry has had a long history, using pendulums, torsion balances, and static spring gravimeters. Relative accuracy adequate for many geophysical problems was already attained by 1900, but it took another half century to build readily portable gravimeters. Calibration and datum definition remained problems until the 1970s when free‐fall absolute gravimeters were developed that now have a precision of 10−3mGal. The problems of geographic inaccessibility and field party costs (notably in areas of greatest tectonic interest) are now being overcome by airborne gravimetry that has already achieved accuracies of 1–3 mGal with resolutions of 10 to 20 km. Satellite techniques are the best way to determine the long‐wavelength variations of the gravity field. The resolution of the models has steadily improved with the number of satellites and the precision of the observations. The best current model includes tracking data from more than 30 satellites, satellite altimetry, and surface gravimetry and has a resolution of about 290 km (harmonic degree 70) with the most recent improvements coming from Doppler orbitography and radiopositioning integrated by satellite (DORIS) tracking of the SPOT 2 satellite and satellite laser ranging (SLR), DORIS, and Global Positioning System (GPS) tracking of the TOPEX/POSEIDON satellite. Meanwhile, radar altimetry has become the dominant technique to infer the marine geoid with a resolution of tens of kilometers or shorter. Similarly, the gravity fiel...