The field of infrasonic research, the science of low-frequency acoustic waves, has expanded to include acoustic-gravity waves and developed into a broad interdisciplinary field encompassing several academic disciplines of geophysics as well as recent technical and basic scientific developments. The International Monitoring System (IMS) infrasound network for nuclear-test-ban verification and regional infrasound arrays deployed around the globe have demonstrated their capacity for detecting and locating various natural and anthropogenic disturbances. Infrasound and acoustic-gravity waves are capable of traveling up to thermospheric altitudes and over enormous ranges, where the wind and temperature structure controls their propagation. Recent studies have offered new insights on quantitative relationships between infrasonic observations and atmospheric dynamics, opening a new field for atmospheric remote sensing.

New studies using lidar, radar, microwave spectrometer, and mesospheric airglow observations complemented by satellite measurements help better determine the interaction between atmospheric layers and the influence of atmospheric waves on the mean flow. It is expected that further developing multi-instrument platforms will improve gravity wave parameterizations and enlarge the science community interested in operational infrasound monitoring. In a higher frequency range, the infrasound monitoring system also offers unique opportunities to provide, in near-real time, continuous relevant information about natural hazards with high societal impact, such as volcanic eruptions, surface earthquakes, meteoroids, and bright fireballs.

We invite contributions on recent studies characterizing infrasound sources or atmospheric phenomena using complementary technologies. We particularly encourage presentations utilizing acoustic waves to probe the atmosphere at both small and large scales. Results and advances in acoustic propagation modeling, signal processing and machine learning applications are also welcome. Another focus is on derived data products and services for civilian and scientific applications as well as on innovative instrumentation, which also encompasses sensors attached to moving or elevated platforms such as balloons. We also invite seismo-acoustic studies on the coupled Earth’s crust – ocean – atmosphere system and, in particular, on the ionospheric manifestations of physical processes in the ocean and in the solid Earth.