Infrasonic waves are small pressure perturbations generated by a variety of natural and artificial sources, such as thunderstorms and severe weather, volcanoes, meteorites, earthquakes, avalanches, rocket launches, supersonic flights and explosions. How these waves propagate in the atmosphere depends on atmospheric background conditions (temperature, wind, pressure, attenuation) and they can be detected over long distances. Therefore, infrasound can be used for remote sensing of natural hazards and for monitoring human activities (like nuclear testing).
Infrasonic effects can furthermore be detected in temperature fluctuations. The expected temperature effects can be modeled and quantified, depending on the intensity of a source signal and its attenuation in the atmosphere (see the figure). In the context of mesopause temperature measurements (at 80-100 km altitudes) by the ground-based airglow spectrometer GRIPS (Ground-based Infrared P-branch Spectrometer) at DLR-DFD, high-resolution temperature time series are studied for infrasound signatures.
The modeling of infrasound contributes to the detection of natural hazards, to the investigation of short-period influences in airglow measurements and to the overall understanding of atmospheric dynamics.