3‐D Regional Ionosphere Imaging and SED Reconstruction With a New TEC‐Based Ionospheric Data Assimilation System (TIDAS)

Abstract

A new TEC‐based ionospheric data assimilation system (TIDAS) over the continental US and adjacent area (20°–60°N, 60°–130°W, and 100–600 km) has been developed through assimilating heterogeneous ionospheric data, including dense ground‐based Global Navigation Satellite System (GNSS) Total Electron Content (TEC) from 2,000+ receivers, Constellation Observing System for Meteorology, Ionosphere, and Climate radio occultation data, JASON satellite altimeter TEC, and Millstone Hill incoherent scatter radar measurements. A hybrid Ensemble‐Variational scheme is utilized to reconstruct the regional 3‐D electron density distribution: a more realistic and location‐dependent background error covariance matrix is calculated from an ensemble of corrected NeQuick outputs, and a three‐dimensional variational (3DVAR) method is adopted for measurement updates to obtain an optimal state estimation. The spatial‐temporal resolution of the reanalyzed 3‐D electron density product is as high as 1° × 1° in latitude and longitude, 20 km in altitude, and 5 min in universal time, which is sufficient to reproduce ionospheric fine structure and storm‐time disturbances. The accuracy and reliability of data assimilation results are validated using ionosonde and other measurements. TIDAS reanalyzed electron density is able to successfully reconstruct the 3‐D morphology and dynamic evolution of the storm‐enhanced density (SED) plume observed during the St. Patrick's day geomagnetic storm on 17 March 2013 with high fidelity. Using TIDAS, we found that the 3‐D SED plume manifests as a ridge‐like high‐density channel that predominantly occurred between 300 and 500 km during 19:00–21:00 UT for this event, with the F2 region peak height being raised by 40–60 km and peak density enhancement of 30%–50%.

Complete Global Total Electron Content Map Dataset based on a Video Imputation Algorithm VISTA

“…These data are available to download with the Madrigal download API. The Madrigal JASON TEC data processing procedures are based on recommendations on the various TOPEX and JASON satellites websites 32 . Specifically, all data points with surface type or ice flags not indicating the measurement was over open water are filtered out.…”

3‐D Regional Imaging of Ionosphere Over Africa Through Assimilating Satellite and Ground‐Based Data

“…(2016) built a regional model over China by assimilating ground‐based GPS TEC and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation TEC with a 3DVAR algorithm into the IRI model. A similar technique has been applied to image the ionosphere over the US by incorporating TEC data from ground‐based GPS and a Jason satellite altimeter, electron density profiles from COSMIC, and incoherent scatter radar into NeQuick (Aa et al., 2022). The IDA4D algorithm has been tested for nowcasting the regional ionosphere over South Korea (Jeong et al., 2022; Mengist, 2019; Mengist et al., 2018, 2019) and over the US (V. V. Forsythe et al., 2021) by assimilating GPS TEC, COSMIC, and ionosonde NmF2 data.…”

Multiple Longitude Sector Storm‐Enhanced Density (SED) and Long‐Lasting Subauroral Polarization Stream (SAPS) During the 26–28 February 2023 Geomagnetic Storm

“…To advance understanding, it is therefore important to compare the similarities and differences between SEDs occurring at different longitude sectors. 3‐D morphology of SED structure: Although SED has been widely studied using two‐dimensional TEC maps as previously mentioned, 3‐D electron density distribution is ultimately required to specify the vertical structures of SED. Recently, some studies using data assimilation or tomography techniques provide a useful step to reconstruct the SED morphology and specify its dynamic variation in the 3‐D domain (Aa et al., 2022; Yue et al., 2016; Zhai et al., 2020). This capability is needed to match those studies which provide altitude‐resolved observations through use of multiple incoherent scatter radar observations as SED produced plasma passes through their fields of view (Foster et al., 2005).…”

“…Moreover, a newly‐derived TEC‐based ionospheric data assimilation system (TIDAS, Aa et al. (2022)) is used to reconstruct the observed regional 3‐D SED structure over the European and North American regions, respectively. The multi‐instrumental and data assimilation analysis of midlatitude storm response relative to SAPS and SED features motivates this study to advance the current understanding of storm‐time midlatitude electrodynamics and dynamics.…”