Inverting ionospheric electron density perturbations to tsunami wave height

Abstract:

Traveling gravity waves (GWs), generated during tsunamigenic earthquakes, leave atmospheric fingerprints when vertically traversing through the Earth’s neutral atmosphere and ionosphere. This reflects on the Earth’s tsunami-atmosphere-ionosphere vertical coupling, and extensive research has been performed the last two decades at national and international level on detecting and understanding the underlying physics of this unique teleconnection from space. Although numerous neutral atmosphere and ionosphere models have simulated the tsunami-atmosphere-ionosphere coupling and have measured the observed ionospheric electron density perturbations caused by it, there still remain large knowledge gaps on how unique these ionospheric perturbations are to the tsunamigenic events and how much information we can extract from such observables. This study uses NCAR’s Data Assimilation Research Testbed (DART) to blend observed tsunami-induced ionospheric electron density perturbations with non-hydrostatic ionospheric model simulations in order to improve the model-to-observation discrepancies of the entire waveform of the tsunami fingerprints in the ionosphere (e.g., amplitude, phase, leading time, and duration). We use DART to understand, within a statistical framework, the tsunami information embedded in ground-based total electron content (TEC) observations. For the first time, we present DART data-driven inversion techniques to invert observed ionospheric TEC perturbations back to tsunami amplitudes. We conclude by providing recommendations on building an inversion system of ionospheric TEC perturbation to tsunami wave properties, which is key to the development of near-real time warning system for societal applications.