What can we do with an atmospheric seismometer moving at 8 km/s?

Abstract:

The solid/ocean/atmosphere coupling of terrestrial planets has been widely investigated through detection and imaging of electron density perturbations in the ionosphere.
Recently, two new observations methods have proven their efficiency: perturbations of airglow emissions and variations of the drag of very low Earth orbit satellites.
The perturbations of these observables are mainly due to air density variations induced by post-seismic infrasounds or atmospheric gravity waves generated by tsunamis.
Even if the airglow emissions present the great advantage of providing an imaging capability, the weakness of the airglow signal induces long integration time, and does not allow to infer high frequency infrasound signals.
Moreover, restrictions on observation conditions and line of sight integration reduce the capability of detailed imaging of atmospheric wavefronts.
On the other hand, variations of the satellite drag provide only one measurement point along the satellite orbit.
However, the unprecedented quality of the data of GOCE mission allows a precise estimate of air density perturbations, but also vertical and cross track winds estimates.
Consequently, this capability to measure the vibrations induced by atmospheric waves along 3 axes is very similar to the one of a ground seismometer.
We first present some polarisation analysis using these data in order to discriminate between infrasonic waves, gravity waves and perturbations induced by thermosphere dynamics.
Then, we summarize some recent developments in numerical modeling of atmospheric and acoustic and gravity wave propagation with SPECFEM software.
Finally, we present how this numerical tool will allow to perform studies comparable to what was done in solid seismology.
We conclude by a prospect on the application of these observables and numerical tools to other terrestrial planets.