A method for the intensification of atomic oxygen green line emission by internal gravity waves

Abstract

Low-frequency internal gravity waves, such as may be generated by seismic activity and nonlinearly propagated through the stably stratified atmosphere to the E layer of the ionosphere, are shown to cause intensification of atomic oxygen green line emission when their amplitude is sufficiently large. The nonlinear equations for the internal gravity waves are derived with the interaction of the induced currents with the geomagnetic field taken into account. When the source of the internal gravity waves is sufficiently strong, nonlinear vortex structures are predicted to be formed in the upper stratosphere and lower ionosphere. These nonlinear vortex structures are damped owing to Joule losses. The vortices provide a mechanism for increasing the concentration of atomic oxygen in the E layer and hence the associated intensity of the green light radiation at 557.7 nm. Data are discussed that report the observation of enhanced green light emission prior to earthquakes; this could lead to a forecasting model if the connection with seismic activity can be established. © 2008 by the American Geophysical Union.