OH airglow SWIR observations: high temporal resolution acquisition for ionospheric seismology proof of concept

Nightglow radiation is a very good marker of high-altitude dynamics. After a first detection of a tsunami signature by a camera in the O+ emission (red airglow at 250km) in 2011, only a few other tsunami detections have been recorded and none have been observed in OH SWIR emission, which is the brightest of all the nightglow emissions and the only compatible for shorter periods signals, such as seismic waves. On the other hand, these acoustic waves associated with earthquakes are systematically detected by other ionospheric instruments (GPS, radar), they have never been directly observed by an airglow camera.  Can they be also detected by airglow?

We present here our strategy for such proof of concept. If achieved, it will provide unique access to seismic waves propagation where ground instruments are not available:  oceans, which cover more than 70% of the Earth's surface, but also to provide the harsh planetary environment of Venus, where airglow also exists and where it is not possible to send spacecraft to the ground.

The recent development of SWIR cameras and the first detection of infrasound in OH radiation in 2020 opened the way for these detections. To better understand the continuous dynamics of the OH layer, we have deployed a first camera at La Réunion island in May 2023. Another one will be installed on the Japanese island of Oshima in February-March 2024 to try to detect the signature of a seismic event if one occurs during the course of this scientific study. The presentation details our methodology for observing the airglow OH perturbations, from the instrument specifications to the first results of almost one year-acquisition at la Réunion and the expected events that we will observe from Japan.