3‐D Ionospheric Imaging Over the South American Region With a New TEC‐Based Ionospheric Data Assimilation System (TIDAS‐SA)

Abstract

This study has developed a new TEC‐based ionospheric data assimilation system for 3‐D regional ionospheric imaging over the South American sector (TIDAS‐SA) (45°S–15°N, 35°–85°W, and 100–800 km). The TIDAS‐SA data assimilation system utilizes a hybrid Ensemble‐Variational approach to incorporate a diverse set of ionospheric data sources, including dense ground‐based Global Navigation Satellite System (GNSS) line‐of‐sight Total Electron Content (TEC) data, radio occultation data from the Constellation Observing System for Meteorology, Ionosphere, and Climate‐2 (COSMIC‐2), and altimeter TEC data from the JASON‐3 satellite. TIDAS‐SA can produce a reanalyzed three‐dimensional (3‐D) electron density spatial variation with a high time cadence, yielding spatial‐temporal resolution of 1° (latitude) × 1° (longitude) × 20 km (altitude) × 5 min. This allows us to reconstruct and study the 3‐D ionospheric morphology with multi‐scale structures. The performance of the data assimilation system is validated against independent ionosonde and in situ measurements through an experiment for a strong geomagnetic storm event on 03–04 November 2021. The results demonstrate that TIDAS‐SA can provide detailed and altitude‐resolved information that accurately characterizes the storm‐time ionospheric disturbances in vertical and horizontal domains over the equatorial and low‐latitude regions of South America.

2‐D Total Electron Content and 3‐D Ionospheric Electron Density Variations During the 14 October 2023 Annular Solar Eclipse

“…The successful utilization of the TIDAS system to reconstruct 3-D ionospheric Ne during the 2017 Great American Solar Eclipse has been demonstrated and validated by . For a more detailed description of the TIDAS algorithms, readers may refer to Aa et al (2022Aa et al ( , 2024. To further examine eclipse-induced ionospheric changes and to verify TIDAS results, we will also analyze electron density profiles and relevant F2-layer peak height parameters obtained from ionosonde measurements.…”

A Statistical Analysis of the Morphology of Storm‐Enhanced Density Plumes Over the North American Sector

“…TIDAS was initially developed for the continental US and adjacent regions (TIDAS-US, Aa et al ( 2022)) with the primary goal of studying midlatitude ionospheric electron density gradients, particularly focusing on the 3-D morphology and evolution of SED. Recently, TIDAS has undergone upgrades to encompass the European sector (TIDAS-EU, Aa et al (2023)) and the South American sector (TIDAS-SA, Aa, Zhang, Erickson, et al (2024)). For a more detailed description of TIDAS algorithm, readers may refer to Aa et al (2022).…”