• electric fields;
  • ionosphere;
  • assimilation

[1] Equatorial satellites can measure key drivers of the low-latitude ionosphere globally and frequently. The electric field and plasma drift instruments of the Communications and Navigation Outage System satellite will provide redundant observations of the most important driver of low-latitude ionosphere structure, that is, the zonal electric field and resulting E × B plasma drift. The electric field data from the San Marco D satellite have been reduced to E × B plasma drift equivalents and are used to, first, examine data ingestion into an ionosphere model for weather sensitive specifications of the ionosphere and, second, explore use of the mesoscale (<1000 km) features in the E × B plasma drift to forecast the spatial mapping of signal scintillation associated with equatorial spread F in the postsunset ionosphere. The ingestion of the global-scale, satellite-based plasma drift observations into an ionosphere model improves electron density specifications over climatology when results are compared with the satellite in situ electron density measurements. Examination of the presunset and postsunset passes of the San Marco D satellite over a specific longitude sector suggests that the mesoscale structure in the zonal electric field can be used to predict the position and spacing of large plasma plumes associated with equatorial spread F in the postsunset ionosphere. A presunset forecast of the postsunset spatial location of plasma plumes can be used to spatially refine forecast maps of signal scintillation.