Wavelet filter analysis of local atmospheric pressure effects on gravity variations
Wavelet filter analysis of local atmospheric pressure effects on gravity variations
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DOI：
10.1007/s00190-005-0486-6
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发表时间：
2005-09
影响因子：
4.4
通讯作者：
Xiaogong Hu;Lintao Liu;J. Hinderer;Heping Sun
中科院分区：
文献类型：
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作者：
Xiaogong Hu;Lintao Liu;J. Hinderer;Heping Sun
提出了一种分析大气压力对重力变化影响的有效方法。它使用由高阶多贝西小波衍生的正交滤波器组处理重力和压力信号。该方法引入了与时间和频率相关的大气压力导纳，从而提供了更多关于压力信号中的频率分量何时以及如何影响重力变化的信息。通过对武汉超导重力站观测数据的分析，证明了小波变换方法的有效性。在0.176 ~ 720 cpd （cycles / d）频率范围内对14个子频带重力和压力信号的分析表明，局地大气压力波动开始对0.52 ~ 1.04 mHz（周期16 ~ 32 min）地震带重力变化产生明显影响，与0.26 ~ 0.52 mHz（周期32 ~ 64 min）长周期地震带重力变化高度相关。在0.704 ~ 11.25 cpd频段（周期128 min ~ 1.42 d），太阳加热引起的大气潮汐谐波对重力残差的干扰作用最大。在0.176 ~ 0.704 cpd频带（周期1.42 ~ 5.69 d），局地气压对重力变化的影响非常强。将四分之一日潮精确滤波到窄频带进一步证明了小波方法的有效性。在去除长期重力变化和长周期大气压力变化后，我们发现局地压力导纳在小时到天的时间尺度上有明显的变化。我们还揭示了在去除太阳加热大气潮汐的影响后，压力导纳在0.176 ~ 0.352 cpd波段（周期2.84 ~ 5.69天）的季节变化。
An efficient method is proposed for the analysis of atmospheric pressure effects on gravity variations. It processes gravity and pressure signals using an orthogonal filter bank derived from high-degree Daubechies wavelets. The method introduces the atmospheric pressure admittance, which is both time- and frequency-dependent, and thus provides more information about when and how the frequency components in the pressure signal influence gravity variations. We demonstrate the efficiency of the wavelet method by applying it to observations from the Wuhan (China) superconducting gravimeter station. The analysis of gravity and pressure signals in 14 sub-bands with different bandwidths covering a frequency range from 0.176 to 720 cpd (cycles per day) reveals that local atmospheric pressure fluctuations start to induce obvious effects on gravity variations in the seismic band 0.52–1.04 mHz (periods 16 to 32 min) and highly correlate with gravity variation in the long-period seismic mode band 0.26–0.52 mHz (periods 32–64 min). The harmonics of solar-heating-induced atmospheric tides play a leading role in interfering with the variation of gravity residuals in the frequency band 0.704–11.25 cpd (periods 128 min to 1.42 day). Local atmospheric pressure effects on gravity variation are very strong in the frequency band 0.176–0.704 cpd (periods 1.42–5.69 day). Accurately filtering quarter-diurnal tides into a narrow band further demonstrates the efficiency of the wavelet method. After removing secular gravity changes and long-period atmospheric pressure variations, we show that there are obvious variations of local pressure admittance on time scales of hours to days. We also reveal seasonal variability of pressure admittances in the band 0.176–0.352 cpd (periods 2.84–5.69 day) after removing the effects of solar-heating atmospheric tides.