[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-15] The effect of Planetary Waves on the day-to-day variability of equatorial plasma bubbles

*Jeffrey Klenzing¹、Jonathon M Smith^2,1、Guiping Liu¹、Sarah McDonald³、Preeti Bhaneja^4,1、Alexa Jean Halford¹ (1.NASA Goddard Space Flight Center、2.Catholic University of America、3.US Naval Research Laboratory、4.Universities Space Research Association)

キーワード：Ionosphere, Plasma Density Irregularities, Planetary Waves

In the equatorial ionosphere, large persistent depletions in nighttime plasma density (sometimes referred to as “bubbles”) can arise when an unstable ionosphere is perturbed by wave activity. In this scenario, a seed perturbation (such as a gravity wave) on the bottomside of the ionosphere grows rapidly as a Rayleigh-Taylor Instability. Despite over 80 years of observations prediction of these plasma bubbles and the resulting ionospheric scintillation remains an outstanding challenge for the Space Weather community because the terrestrial IT system is driven through multiple energy paths. This talk will discuss the geophysical drivers that can enhance or suppress this instability in the ionosphere — such as geomagnetic storms and planetary waves — which can influence whether a seed wave will grow into a bubble on a given night at a given location.



Previously, the day-to-day variability of the ionosphere due to lower atmospheric forcing was quantified by driving the SAMI3 model with the Whole Atmosphere Community Climate Model eXtended (WACCM-X) with the lower boundaries specified by the High Altitude Navy Global Environment Model (NAVGEM-HA) over an extended period of time. The variability levels of Total Electron Content from ground-based GPS measurements were found to be similar to those predicted by the model. Here we extend this analysis to investigate the day-to-day variability of the Rayleigh-Taylor Instability growth rate as calculated from SAMI3/WACCM-X/NAVGEM and its effect on the growth or suppression of plasma bubbles. We will compare with data to quantify the contribution of Planetary Waves and lower atmospheric forcing on bubbles and subsequent scintillation.