Sensitivity of pre-reversal enhancement on thermosperic tides in the Whole Atmosphere Model

Several studies have demonstrated a strong correlation between the equatorial pre-reversal enhancement of vertical drifts after sunset and equatorial plasma bubbles, which result in adverse effects on communication and global position systems. PRE has been observed well over the past few decades in both ground- and space-based observations, however, modeling its day-to-day variability in a whole atmosphere model remains a challenge. A recent study by Hysell et al. (2022) using the Whole Atmosphere Model and Ionosphere Plasmasphere Electrodynamics (WAM-IPE) model and regional ionospheric irregularity model demonstrated that the accuracy of irregularity reproduction depended significantly on the bottomside background zonal electric fields and zonal thermospheric winds of WAM. In this study, our goal is to further understand the sensitivity of PRE on the amplitudes and phases of different tidal modes in the E-region. One of the ways this is achieved is by nudging the background winds of WAM model in the MLT region to the empirical HWM model, which changes the filtering, and therefore amplitudes and phases of tides as they propagate to higher altitudes. SW2 and DE3 show the largest changes, while also affecting both the timing and amplitude of PRE. Thus, the phase of tides, i.e., the timing of the reversal of the winds from westward to eastward relative to the onset of PRE is a crucial factor. We further employ the SAED model which is a global model designed for solving steady‐state ionospheric electrodynamics equation. We perform experiments removing different tidal components from the background winds and investigate the resulting effects on PRE.