Characteristics of atmosphere‐generated seismic noise below 0.05 Hz are investigated when surface pressure is large. In this paper, large pressure means pressure power spectral density exceeding 100 Pa²/Hz (at 0.01 Hz). We discuss three main points. The first point is existence of two frequency ranges that show high coherence between co‐located pressure and vertical seismic data. The lower frequency (LF) range is broad and its upper bound is about 0.002 Hz. The higher frequency (HF) range is bounded between about 0.01 and 0.05 Hz. Phase difference between pressure and vertical displacement is different for the two ranges. The LF range shows phase difference of zero, and the HF range shows phase difference of 180°. The second point is on the excitation mechanism in the HF range. Using theory and data, we show that seismic noise in the HF range is primarily excited by wind‐related pressure. When pressure is high, wind speeds become high, and wind directions become unidirectional. In such a case, a deterministic, moving pressure‐source by Sorrells (1971, https://doi.org/10.1111/j.1365-246X.1971.tb03383.x) captures the characteristics of data better than stochastic source models. The third point is on the cause of phase differences between the LF range and the HF range. The root cause is that, even after removing the instrument response, vertical seismic data contain effects from gravity and Earth rotation. Gravity effects become significant for frequencies below 0.005 Hz and create discrepancies between deconvolved vertical displacements and true vertical ground displacements. Phase‐difference results are naturally explained by it.

中文翻译：

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低频，大气产生的地震噪声的性质

当表面压力较大时，研究了低于0.05 Hz的大气产生的地震噪声的特征。本文中，大压力意味着压力功率谱密度超过100 Pa ²/Hz（0.01 Hz时）。我们讨论了三个要点。第一点是存在两个频率范围，这两个频率范围显示共处的压力和垂直地震数据之间的高度一致性。低频（LF）范围较宽，上限约为0.002 Hz。较高的频率（HF）范围限制在约0.01和0.05 Hz之间。在这两个范围内，压力和垂直位移之间的相位差是不同的。LF范围的相位差为零，HF范围的相位差为180°。第二点是在HF范围内的激励机制。使用理论和数据，我们表明HF范围内的地震噪声主要是由与风有关的压力激发的。压力高时，风速变高，风向变为单向。在这种情况下，确定性的 Sorrells（1971，https://doi.org/10.1111/j.1365-246X.1971.tb03383.x）的移动压力源捕获数据的特征优于随机源模型。第三点是LF范围和HF范围之间出现相位差的原因。根本原因是，即使在消除仪器响应后，垂直地震数据也会包含重力和地球自转的影响。对于低于0.005 Hz的频率，重力效应变得很明显，并且会在反卷积的垂直位移与真实的垂直地面位移之间产生差异。相位差结果自然可以用它来解释。根本原因是，即使在消除仪器响应后，垂直地震数据也会包含重力和地球自转的影响。对于低于0.005 Hz的频率，重力效应变得很明显，并且会在反卷积的垂直位移与真实的垂直地面位移之间产生差异。相位差结果自然可以用它来解释。根本原因是，即使在删除仪器响应后，垂直地震数据也会包含重力和地球自转的影响。对于低于0.005 Hz的频率，重力效应变得很明显，并在反卷积的垂直位移和真实的垂直地面位移之间产生差异。相位差结果自然可以用它来解释。