The PIs will use extensive measurements and numerical modeling to study the generation and evolution of spread-F irregularity and scintillation phenomena, and obtain a global semi-empirical equatorial electrodynamic and spread-F model with predictive capabilities. Using Jicamarca incoherent radar, global ionosonde and satellite measurements the investigators will determine the initial electrodynamic conditions for spread-F. Their radar data set will determine the height dependent ambient electrodynamic conditions immediately prior to the occurrence of spread-F, the location of the initial unstable layer, and its temporal and spatial evolution for different seasons and flux conditions. Height gradients in the vertical and zonal plasma drifts in the bottomside and topside of the F layer may play important roles in the generation and evolution of equatorial spread-F. Additionally, the PIs will use extensive ionosonde and satellite data to determine the role of meridional neutral winds and magnetic declination effects, and extend the model to different longitudinal sectors. Finally, they will combine the Jicamarca radar drift model, the AE-E satellite model and ionosonde observations with the storm time electric field model at Utah State and the GTIM to obtain the first global equatorial electrodynamic and spread-F model.
