Initial results of a rocket-based study of gravity wave effects on photoionization in the middle atmosphere

Abstract

During May, 2002, two Nike Orion sounding rocket payloads were launched from NASA Wallops Flight Facility, Virginia, to explore the effects of gravity waves on the electrodynamics of the mesosphere. This effort extended earlier work that focused on observed correlations between mesospheric temperatures and conductivities. One result of that work was the postulation of subvisible “ice” particles throughout the mesosphere. Because the preferential size of the aerosols depends on the temperature (and therefore also on gravity wave activity), the present effort investigated the influences of thunderstorm-produced gravity waves on the aerosols. Although the extremely small size of these particles makes direct optical observation of them impossible, in situ observations of their ionization by UV radiation was used to show the electrodynamic effects of temperature variations in the lower mesosphere and upper stratosphere. One rocket flight occurred on a clear night with no nearby tropospheric source mechanisms, and the other flight occurred after the passage of a strong thunderstorm system in the vicinity of the rocket range. The effects of gravity waves generatged by the thunderstorms in the lower mesosphere were also observed by an inflatable falling sphere and ground-based observations of the OH layer.