Observations of ionospheric irregularities during a geomagnetic storm based on the C-band sentinel-1

• Published in: International journal of remote sensing 2024-09, Vol.45 (18), p.6425-6444
• Main Authors: Zhu, Yixun, Xiong, Chao, Wan, Xin, Ji, Yifei, Tao, Zhiwei, Tang, Feixiang, Gao, Shunzu, Wang, Fengjue, Huang, Yuyang
• Format: Article
• Language: English
• Subjects: C band; Electron density; Geomagnetic storms; Geomagnetism; Global navigation satellite system; INSAR; Interferometric synthetic aperture radar; Interferometry; Ionosphere; Ionospheric irregularities; ionospheric total electron count; Irregularities; Magnetic storms; Navigation; Navigation satellites; Navigation systems; Navigational satellites; SAR; SAR (radar); Satellites; Storms; Structures; Synthetic aperture radar; Synthetic aperture radar interferometry; Total Electron Content
• ISSN: 0143-1161; 1366-5901
• DOI: 10.1080/01431161.2024.2388879

Disturbances in the ionosphere can severely affect synthetic aperture radar (SAR) acquisition and also the accuracy of differential SAR interferometry (D-InSAR) techniques. Focusing on the mid-latitudes, we report for the first time the effect of small-scale ionospheric irregularities on the interferograms generated by the C-band Sentinel-1 satellite. The interferograms obtained during the geomagnetic storm on 4 November 2021 showed finger-like stripes of phase artefacts, while the interferograms obtained on non-storm days did not show such anomalies. Such phase artefacts introduce an error greater than ± 3π in the interferogram. By further checking the gridded total electron content (TEC) from the ground-based global navigation satellite system (GNSS) network, as well as the in-situ electron density measured by ESA's Swarm satellite, the finger-like stripes in the interferograms are found to be correlated with ionospheric bulge structures generated during the geomagnetic storm. Since both the interferogram stripes and the ionospheric bulges exhibit a comparable east-west extension, it is believed that the interferograms can also be used to reflect the small-scale structures of ionospheric bulge fringes. For example, in this case, the latitudinal width of each finger-like stripe reaches about 8 km. Our result implies that the C-band interferogram has the potential to probe the two-dimensional ionospheric structures with unprecedented resolution, which cannot be achievable by the gridded GNSS-TEC.