Rapid ocean signals in polar motion and length of day
Rapid ocean signals in polar motion and length of day
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DOI：
10.1029/2002gl015312
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发表时间：
2002-08
影响因子：
5.2
通讯作者：
R. Ponte;A. H. Ali
中科院分区：
文献类型：
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作者：
R. Ponte;A. H. Ali
洋流和海底压力的非潮汐变化在短期内很大，但将海洋角动量(OAM)中的相关信号与观测到的极地运动和日长波动联系起来一直是困难的。我们使用正压海洋模式进行的模拟表明，在3-10天的周期内，估计的OAM信号与极地运动和日长之间存在明显的联系。海洋对大气压的动力响应在激发快速旋转信号方面起着重要作用。当使用基于GPS的时间平滑很少的地球定向测量时，OAM可变性的影响最为明显。使用GPS系列，并考虑到大气影响以外的OAM，在快速极地运动和日长的激发预算方面产生了实质性的改善。与地球自转数据的比较为正压模式模拟的快速海洋变率提供了有用的检验。
Non‐tidal variability in ocean currents and bottom pressure is substantial at short periods, but relating the associated signals in ocean angular momentum (OAM) to observed polar motion and length of day fluctuations has been difficult. Our simulations using a barotropic ocean model reveal a clear connection between the estimated OAM signals and both polar motion and length of day at periods of 3–10 days. The dynamic response of the oceans to barometric pressure plays an important role in the excitation of rapid rotation signals. The impact of OAM variability is most clear when using GPS‐based Earth orientation measurements with little temporal smoothing. Using the GPS series, and accounting for OAM in addition to atmospheric effects, yields substantial improvements in the excitation budget for rapid polar motion and length of day. The comparisons with Earth rotation data provide a useful check on the rapid ocean variability simulated by the barotropic model.