Atmospheric gravity waves due to the Tohoku-Oki tsunami observed in the thermosphere by GOCE

Raphael Garcia (1, 2, 3) , Eelco Doornbos (4) , Sean Bruinsma (5) , Hélène Hebert (6)

1 OMP - Observatoire Midi-Pyrénées
2 DEOS - Département Electronique, Optronique et Signal
3 IRAP - Institut de recherche en astrophysique et planétologie
4 TU Delft - Delft University of Technology
5 Space Geodesy Department
6 LDG - Laboratoire de Détection et de Géophysique (CEA)

Oceanic tsunami waves couple with atmospheric gravity waves, as previously observedthrough ionospheric and airglow perturbations. Aerodynamic velocities and density variations are computed from Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) accelerometer and thruster data during Tohoku-Oki tsunami propagation. High-frequency perturbations of these parameters are observed during three expected crossings of the tsunami-generated gravity waves by the GOCE satellite. From theoretical relations between air density and vertical and horizontal velocities inside the gravity wave, we demonstrate that the measured perturbations are consistent with a gravity wave generated by the tsunami and provide a way to estimate the propagation azimuth of the gravity wave. Moreover, because GOCE measurements can constrain the wave polarization, a marker (noted C 3 ) of any gravity wave crossing by the GOCE satellite is constructed from correlation coefficients between the observed atmospheric state parameters. These observations validate a new observation tool of thermospheric gravity waves generated by tsunamis above the open ocean.

Mots clés: Atmospheric gravity waves; GOCE; Tsunami; Satellite drag

Domaines: Océan, Atmosphère

Raphael Garcia, Eelco Doornbos, Sean Bruinsma, Hélène Hebert. Atmospheric gravity waves due to the Tohoku-Oki tsunami observed in the thermosphere by GOCE. Critical Care, 2014, vol. 119 (n° 8), pp. 4498-4506. ⟨10.1002/2013JD021120⟩. ⟨hal-01110883⟩