[S-TT40] Synthetic Aperture Radar and its application

[STT40-09] Impact of the Geomagnetic Storm in May 2024 on ALOS-2/PALSAR-2 Imagery

*Masato Furuya¹, Ihsan Naufal Muafiry² (1.Department of Earth and Planetary Sciences Hokkaido University, 2.BRIN)

Keywords:geomagnetic storm, ionosphere, ALOS-2, Synthetic Aperture Radar, Total Electron Content

The strongest geomagnetic storm over the last 20 years occurred in May 2024. In particular, from 11-12 May, low-latitude auroras could be observed even at northern Hokkaido. Here we examine its impact on the ALOS-2/PALSAR-2 imageries. ALOS-2/PALSAR-2 was performing its full-polarimetric SAR observations at a couple of tracks in Japan from May 10-12. We have analyzed the imageries acquired at an track near Hokkaido at 23:18 JST on 11 May 2024. To examine the effect of the ionospheric disturbances on the SAR image, we first split the original single-look-complex (SLC) images into forward- and backward-looking SLC images and then computed their offset field. Although this is not an interferometry, this approach is similar to the multiple-aperture interferometry that allows us to derive the along-azimuth gradient of total electron content (TEC) and azimuth displacements (if any). The derived apparent azimuth displacements were ranging -15 meters to +15 meters, which is greater than those we found during the sporadic-E episodes (Fujimoto et al. 2024). Regarding the spatial scale, the apparent azimuth displacements ranged from ~5-20km. However, those apparent displacements were restricted to only the southern-half portion of the entire imaged area.