Persistence of the Prereversal Enhancement of the Equatorial Vertical Plasma Drifts Observed by ICON

Abstract An important feature of equatorial ionospheric electrodynamics is the evening prereversal enhancement (PRE) of the eastward electric fields and the associated vertical plasma drifts. The magnitude, timing, and duration of the PRE are closely connected to the development of postsunset F‐region irregularities. If the PRE evolves slowly as it follows the day/night terminator, a persistence‐based forecasting strategy may be valuable in predicting the PRE. In this study, we use ICON satellite data from November 2021 to October 2022 to monitor the PRE across sequential orbits. PRE drifts are parameterized to a Gaussian curve superimposed on a background linear trend. Rapid evolution of the PRE manifests as differences in parameters between orbits. Results indicate that the magnitude, timing, and duration of the PRE can change significantly between orbits, limiting the validity of persistence‐based forecasting of the PRE. As the separation between observations increases, the strength of persistence decreases.