Journal Article

Equatorial Ionization Anomaly Discontinuity Observed by GOLD, COSMIC‐2, and Ground‐Based GPS Receivers' Network

Daniell, Robert E., Eastes, Richard W., Qian, Liying, Zhang, Shunrong, Aa, Ercha, Cai, Xuguang, Coster, Anthea, Pedatella, Nicholas.M., McClintock, William E., Wang, Wenbin

2023

Overview

We report a new ionosphere phenomenon: Equatorial ionization anomaly (EIA) discontinuity (EIAD), based on OI 135.6 nm radiance observations from the Global Observations of Limb and Disk (GOLD), ground‐based total electron content maps and in‐situ ion density data from Constellation Observing System for Meteorology, Ionosphere, and Climate‐2. The EIAD occurs when the OI radiance of the EIA crest has a local minimum, at a fixed UT, with the radiance in the local longitude region being weaker than that on the east and west sides. In the GOLD field‐of‐view, EIAD follows the seasonal variations of EIA. EIAD appears more often over the Atlantic Ocean and Africa than over South America. It occurs more in the southern crest during the December solstice, and more in the northern crest during both equinoxes. EIAD can occur under both quiet and disturbed times. Plain Language Summary The equatorial ionization anomaly (EIA) is very dynamic and can exhibit various structures. Here we report a newly discovered EIA structure: EIA discontinuity, namely the EIA crest shows a lower electron density in the middle longitude range than in east and west longitude ranges. We first show the observation of EIA discontinuity observed concurrently by a geo‐stationary orbit satellite, a low‐earth‐orbit satellite and ground‐based global positioning system receiver. Then a statistical study illustrates that the EIA discontinuity is mostly captured in field‐of‐view of the geo‐stationary satellite in one hemisphere. It obeys the seasonal variation of EIA. The occurrence is higher in the spring equinox than in the fall equinox. Near the December solstices, it appears more in the southern crest. In both equinoxes, it appears more often in the northern crest. In August, its occurrence increases with the increase of solar irradiance. The EIA discontinuity can occur under both geomagnetically quiet and disturbed times. Key Points Equatorial ionization anomaly (EIA) discontinuity is the EIA crest with a weaker electron density in a longitude region than longitudes to the east and west Statistical study shows that its occurrence has a preference in Atlantic Ocean and Africa than America within the Global Observations of Limb and Disk field‐of‐view EIA discontinuity can occur under both geomagnetically quiet and disturbed times

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Constellation Observing System for Meteorology, Ionosphere and Climate / Discontinuity / Electron density / Equatorial ionization anomaly / equatorial ionosphere / Equinoxes / Global positioning systems / Gold / GPS / Ion density / Ion density (concentration) / Ionization / Ionosphere / Irradiance / Longitude / Meteorology / Positioning systems / Radiance / Satellites / Seasonal variation / Seasonal variations / Solar irradiance / Solstices