A new assessment of long-wavelength gravitational variations
A new assessment of long-wavelength gravitational variations
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DOI：
10.1029/2000jb900115
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发表时间：
2000-07-10
影响因子：
3.9
通讯作者：
Tapley, BD
中科院分区：
文献类型：
--
作者：
Chen, JL;Wilson, CR;Tapley, BD
我们估计2度长波引力变化C-21，S-21，和C-20使用地球自转的变化，引起的质量重新分配和地球系统内的运动。这些旋转变化是通过空间大地测量技术精确测量的。风和洋流的影响，从地球自转系列使用大气和海洋环流数据同化模式。结果进行了比较LAGEOS卫星激光测距（SLR）的决心，也与地球物理的贡献估计从大气表面压力，大陆储水量，和nonsteric海平面变化。我们的推测是，在某些情况下，利用地球自转变化来推断长波引力变化可能比基于卫星的技术更准确。与此相一致，我们发现本研究中C-21和S-21的变化与地球物理观测结果的一致性优于LAGEOS SLR对C-21和S-21的测定。由地球自转得出的C-20变化的估计值可能不如由LAGEOS得出的结果准确，因为大气风对C-20长度的影响很大，必须首先消除日变化，LAGEOS对C-20的自然敏感性通过卫星节点的岁差而变化。
We estimate the degree 2 long-wavelength gravitational variations C-21, S-21, and C-20 using Earth rotational changes, caused by mass redistribution and movement within the Earth system. These rotation changes are accurately measured by space geodetic techniques. Wind and oceanic current effects are removed from the Earth rotation series using atmospheric and oceanic circulation data-assimilating models. The results are compared with LAGEOS Satellite Laser Ranging (SLR) determinations and also with geophysical contributions estimated from atmospheric surface pressure, continental water storage, and nonsteric sea level changes. Our conjecture is that using Earth rotational changes to infer long-wavelength gravitational variations has the potential to be more accurate than satellite-based techniques in some cases. Consistent with this, we find that C-21 and S-21 variations from this study are in better agreement with geophysical observations than LAGEOS SLR determinations of C-21 and S-21 However, the Earth rotation-derived estimate of C-20 variation is probably less accurate than the LAGEOS-derived result owing to the large atmospheric wind contribution to length-of-day variation which must first be removed and the natural sensitivity of LAGEOS to C-20 changes via precession of the satellite node.