Interannual variability of low-degree gravitational change, 1980–2002
Interannual variability of low-degree gravitational change, 1980–2002
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DOI：
10.1007/s00190-004-0417-y
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发表时间：
2005-03
影响因子：
4.4
通讯作者：
Jianli Chen;C. Wilson;B. Tapley
中科院分区：
文献类型：
--
作者：
Jianli Chen;C. Wilson;B. Tapley
根据精确测量的地球自转变化，估算了周期大于1年的2度球谐函数Δ C21、Δ S21和Δ C20的地球重力场时间变化。这些与大气，海洋和水文模型的预测，并与独立的卫星激光测距（SLR）的结果进行比较。在22年的时间里，地球自转与模式预测的Δ C21和Δ S21有着非常好的一致性。在去除年代际信号后，由地球自转引起的Δ C20年际变化主要是一个5.6年左右的强振荡，这可能是由于风和海流估计的不确定性造成的。除了1997/1998年以来的最近异常外，模式预测的Δ C20与22年期间的SLR观测相当吻合。
Time variations in the Earth’s gravity field at periods longer than 1 year, for degree-two spherical harmonics, ΔC21, ΔS21, and ΔC20, are estimated from accurately measured Earth rotational variations. These are compared with predictions of atmospheric, oceanic, and hydrologic models, and with independent satellite laser ranging (SLR) results. There is remarkably good agreement between Earth rotation and model predictions of ΔC21and ΔS21over a 22-year period. After decadal signals are removed, Earth-rotation-derived interannual ΔC20variations are dominated by a strong oscillation of period about 5.6 years, probably due to uncertainties in wind and ocean current estimates. The model-predicted ΔC20agrees reasonably well with SLR observations during the 22-year period, with the exception of the recent anomaly since 1997/1998.