Evidence of Tropospheric Effects on the Ionosphere



A new paradigm in upper atmospheric and ionospheric physics has begun to emerge, starting with discoveries from observations taken with the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite in 2002. These discoveries [Immel et al., 2006] show that the entire ionosphere, sometimes referred to as “the inner edge of space,” regularly responds to the tropospheric weather systems below. The likely mechanism for effectively carrying tropospheric energy upward to the edge of space to modify the ionosphere is the generation and upward propagation of large-scale waves, known as atmospheric tides. The coupling of these tides to the ionosphere is inferred from the strong similarity in longitudinal structure of the tidal winds and the ionospheric densities at low latitudes. However, the appearance of this behavior in the upper ionosphere is surprising because the tides that are forced by tropospheric weather are believed to dissipate at the base of the ionosphere and are expected to have little effect at higher altitudes.