Measurement of the Earth's rotation: 720 BC to AD 2015.
Measurement of the Earth's rotation: 720 BC to AD 2015.
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地球旋转的测量：公元前720年至AD 2015。
DOI：
10.1098/rspa.2016.0404
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发表时间：
2016-12
期刊：
影响因子：
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通讯作者：
Hohenkerk CY
中科院分区：
文献类型：
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作者：
Stephenson FR;Morrison LV;Hohenkerk CY
对公元前720年至公元1600年期间古代和中世纪日食记录以及公元1600年至2015年月球掩星记录的新汇编进行了分析，以调查地球自转速率的变化。发现自转速率偏离均匀性，平均太阳日长度（lod）的变化以每世纪+1.8 ms的平均速率增加。这明显低于根据潮汐摩擦预测的速率，即每世纪+2.3毫秒。除了LOD的这种线性变化之外，这种趋势在几十年到几百年的时间尺度上也有波动。对2-30年波动的功率谱密度分析遵循指数为-1.3的幂律，有证据表明在6年周期内功率增加。有一些迹象表明，lod的振荡周期约为1500年。我们对公元前720年至公元2015年期间地球自转的测量为未来关于冰后期反弹和核幔耦合的工作设定了明确的界限，这些工作被用来解释潮汐摩擦的偏离。
New compilations of records of ancient and medieval eclipses in the period 720 BC to AD 1600, and of lunar occultations of stars in AD 1600–2015, are analysed to investigate variations in the Earth’s rate of rotation. It is found that the rate of rotation departs from uniformity, such that the change in the length of the mean solar day (lod) increases at an average rate of +1.8 ms per century. This is significantly less than the rate predicted on the basis of tidal friction, which is +2.3 ms per century. Besides this linear change in the lod, there are fluctuations about this trend on time scales of decades to centuries. A power spectral density analysis of fluctuations in the range 2–30 years follows a power law with exponent −1.3, and there is evidence of increased power at a period of 6 years. There is some indication of an oscillation in the lod with a period of roughly 1500 years. Our measurements of the Earth’s rotation for the period 720 BC to AD 2015 set firm boundaries for future work on post-glacial rebound and core–mantle coupling which are invoked to explain the departures from tidal friction.