Numerical Modeling of Tsunami-Generated Acoustic-Gravity Waves in Mesopause Airglow

Numerical simulations of mesopause airglow (MA) fluctuations induced by tsunami-generated acoustic and gravity waves (TAGWs) are performed. Simulated tsunamis over realistic bathymetry are used to excite atmospheric waves at the surface level of a three-dimensional nonlinear and compressible neutral atmospheric model. The model incorporates the dynamics and chemistry of hydroxyl OH(3,1) MA under nighttime assumptions. We report case study results of eight recent large tsunami events and demonstrate that TAGW-induced MA fluctuations are readily detectable with modern ground- and space-based imagers, and may provide quantitative insight. The amplitudes of MA fluctuations reflect the evolution of ocean surface displacements, enhancing or decreasing accordingly, and revealing the tsunami's lobes and local wave focusing. The results suggest that MA observations have potential to supplement early-warning systems, providing information on spatial and temporal evolution of tsunami waves of ∼10 cm and higher for the cases shown. They may find applications in tsunami tracking over large open ocean areas, as well as in the investigation or reconstruction of tsunami source characteristics.