Longitudinal and Seasonal Variability of Equatorial Ionospheric Irregularities and Electrodynamics

Abstract

Over the past decades significant progresses have been done to understand the origin of seeding mechanisms of ionospheric irregularities. However, characterization of the global ionospheric irregularities as a function of local time, longitude, and season is still a challenge for the modeling community. In this review paper, using multiinstrument observations, we investigated the global irregularity distribution and its possible drivers that control the longitudinal and seasonal dependences. We demonstrated that forcing from lower thermosphere, like the localized tropospheric gravity waves seeding, may be responsible for the formation of strong longitudinal dependence of irregularity distribution. The location of Intertropical Convergence Zone that generate forceful thunderstorms and become favorable location for the launch of localized gravity waves may play an important role in the longitudinal dependence of irregularity distribution. Hence, incorporating the Intertropical Convergence Zone location into density irregularity modeling effort may provide important information to understand and characterize the longitudinal variability of irregularity distributions.