| 大气对极移的非季节性激发贡献 |
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| 引用本文： | 钱昌夏,顾震年.大气对极移的非季节性激发贡献[J].天文学报,1996,37(2):124-131. |
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| 作者姓名： | 钱昌夏 顾震年 |
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| 作者单位： | 中国科学院上海天文台 |
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| 摘 要： | 本文对由高精度的极移资（Ｓｐａｃｅ９３序列）所推导出的测地激发函数和由日本气象局（ＪＭＡ）提供的大气激发函数中的非季节性波动进行了研究，在两个序列中都显示出较强的４０－６０天的波动．在非季节性的时间尺度上，测地激发函数相关于大气压力变化，与与的相关系数分别为０．４４和０．５８，这表明了大气角动量对极移中ｙ轴方向的非季节性变化的影响稍大于ｘ轴方向．而且，大气和测地激发函数尤其在Ｘ２方面具有较相似的时间变化谱．这些事实说明：极移的非季节振荡至少部分地由气压变化所引起，它在１４０天以下周期的极移激发中起了一定的作用．
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| 关 键 词： | 测地激发，大气激发，非季节性波动 |
CONTRIBUTIONS OF ATMOSPHERIC EXCITATION TO NONSEASONAL POLAR MOTION |
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| Qian Chang-xia, Gu Zhen-nian.CONTRIBUTIONS OF ATMOSPHERIC EXCITATION TO NONSEASONAL POLAR MOTION[J].Acta Astronomica Sinica,1996,37(2):124-131. |
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| Authors: | Qian Chang-xia Gu Zhen-nian |
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| Abstract: | In this paper, the geodetic excitation set derived by the new highly accurate perfar motion data (space 93 series) and the atmospheric excitation function compiled byJapan Meteorological Agency (JMA) are used to investigate the nonseasonalcollation. A relatively strong 40 to 60-days oscillation is revealed from these dataseries. The geodetic excitation is related to the atmospheric pressure change onnonseasonal timescale. The coherence estimates between the series are of the order of0.44, and 0.58 for and , respectively. Thus, these estimates imply that thecontribution of atmospheric equatorial angular momentum (EAM) to the nonseasonaloscillation of polar motion in the direction of Y-axis is slightly larger than that inthe direction of X-axis. The nonseasonal oscillations of the atmospheric and geodeticexcitation functions have similar time-varying spectra, espedally in the cass of X2components. These facts seem likely that the nonseasonal oscillation is at least partially driven by surface air pressure change, which plays role of the excitation in the polar motion with periods less than 140 days. |
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| Keywords: | Geodetic excitation Atmospheric excitation Nonsesonal oscillation |
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