Acoustic waves in planetary atmospheres couple into the solid surface, producing ground displacements that can be measured using seismometers. On 26 November 2018, the InSight mission successfully landed on Mars. Its objectives include studying Mars' interior using the seismometer SEIS (Seismic Experiment for Interior Structures) and the atmosphere through the weather station APSS (Auxiliary Payload Sensor Suite). Because InSight is the first mission capable of studying infrasound on Mars, we investigate the signature of infrasound both in terms of air pressure and ground velocities. Using numerical simulations, we characterize (1) the acoustic propagation pattern in Martian dusk and (2) the mechanical atmosphere‐to‐ground coupling under acoustic waves. Then, using SEIS data, we demonstrate that two low‐frequency monotone events (S0133a and S0189a) are in fact infrasound trapped in the atmospheric nocturnal surface waveguide. We base our demonstration on the following facts. (1) Seismic signals rarely produce, at a given station, a single frequency varying from one event to the other. (2) No clear seismic phases have been identified for such events. (3) The observed SEIS signals present the characteristics expected for trapped infrasound observed through their compliance effects (specific frequency response, more energy on the vertical component, ±90° phase shift between vertical and horizontal components, and no detection on pressure sensor at these low amplitude levels). Our simulations of the nocturnal waveguide's response are however subject to uncertainties because (1) it relies on the sol‐to‐sol variability of the atmosphere, and (2) subsurface properties are not properly known at this time.

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火星次声：InSight数据的数值建模和分析

行星大气中的声波耦合到固体表面，产生可以使用地震仪测量的地面位移。2018年11月26日，InSight任务成功登陆火星。它的目标包括使用地震仪SEIS（内部结构地震实验）研究火星内部，并通过气象站APSS（辅助有效载荷传感器套件）研究大气。因为InSight是第一个能够研究火星次声的任务，所以我们从气压和地面速度两方面研究次声的特征。使用数值模拟，我们表征（1）火星黄昏中的声传播模式和（2）声波下大气与地面的机械耦合。然后，使用SEIS数据，我们证明了两个低频单调事件（S0133a和S0189a）实际上是次声被困在大气夜面波导中。我们的示范基于以下事实。（1）地震信号很少在给定的位置产生从一个事件到另一个事件变化的单个频率。（2）尚未确定此类事件的明确地震阶段。（3）观察到的SEIS信号具有通过其顺应性效应观察到的被捕获次声的预期特征（特定频率响应，垂直分量上的更多能量，垂直分量与水平分量之间的相移为±90°，并且在这些位置均未检测到压力传感器）低振幅水平）。我们对夜间波导的模拟