Showing papers by "Michael P. Hickey published in 2017"
TL;DR: In this article, the authors employ a linear full-wave model and a nonlinear time-dependent model to examine the ionospheric response to the atmospheric gravity wave perturbations induced by the 2004 Sumatra and the 2011 Tohoku tsunamis.
Abstract: Ionospheric fluctuations inferred from observations of total electron content have previously been attributed to tsunamis and have confirmed the strong coupling between Earth’s ocean and ionosphere via atmospheric gravity waves (AGWs). To further advance our understanding of this wave coupling process we employ a linear full-wave model and a nonlinear time-dependent model to examine the ionospheric response to the AGW perturbations induced by the 2004 Sumatra and the 2011 Tohoku tsunamis. In the 2004 case, our modeling analyses reveal that one component of the propagating AGWs becomes dynamically unstable in the E-region ionosphere at a range exceeding 2000 km in a direction 340° clockwise from north. Another component becomes convectively unstable in the E-region ionosphere at a range exceeding 700 km in a direction 250° clockwise from north. In the 2011 case, a significant enhancement in the ionospheric disturbance occurs in a direction northwest from the epicenter about 1 h following the tsunami onset, in general agreement with observations. Our simulations also indicate that the AGW propagating toward the southeast is responsible for a traveling ionospheric disturbance that remains of an observable amplitude for over 4 h during which time it propagates horizontally almost 4000 km.
19 citations
TL;DR: In this article, a 2D nonlinear model was proposed to explain the observations of tsunamigenic traveling ionospheric disturbances (TIDs) associated with the 2011 Tohoku event, where wave sources were modeled as triads of nonlinearly interacting oceanic gravity waves, whose wave parameters satisfy resonant conditions.
Abstract: Ionospheric observations associated with the 2011 Tohoku tsunami have revealed gravity waves having spectral characteristics that depend on their proximity to the epicenter. There is a preponderance of medium scale waves in the vicinity of the epicenter, a significant bifurcation into short and long period waves over the Hawaiian archipelago, and a narrow and rich spectrum of waves over the west coast and inland of the United States (US). Guided by these previous observations, we consider wave sources as triads of nonlinearly interacting oceanic gravity waves, whose wave parameters satisfy resonant conditions. These waves are simulated using a 2-D nonlinear model describing gravity wave propagation in order to explain the observations of tsunamigenic traveling ionospheric disturbances (TIDs) associated with the Tohoku event.
3 citations