[P-EM10] Space Weather and Space Climate

[PEM10-P15] Comparison of two methods of auroral altitude estimation based on two-point observations

*Kyutaro Yanagisawa¹, Daniel Whiter², Ryuho Kataoka³, Kanako Seki¹, Yoshizumi Miyoshi⁴, Kazuo Shiokawa⁴, Martin G Connors⁵, Satoshi Nakahira⁶, Shoji Torii⁷ (1.Graduate School of Science, University of Tokyo, 2.School of Physics & Astronomy, University of Southampton, 3.National Institue of Polar Research, 4.Institue for Space-Earth Environmental Research, Nagoya university, 5.Athabasca university, 6.Japan Aerospace eXploration Agency, 7.Waseda Research Institute for Science and Engineering)

High-energy electrons trapped in the radiation belt can sometimes precipitate into the atmosphere, causing relativistic electron precipitation (REP) events. The emission altitude of the REP-related aurora depends on the energy of precipitating electrons or protons, which can contribute to identifying the possible wave mode which caused the REP. We have identified REP events using the CALorimetric Electron Telescope (CALET) experiment on-board the International Space Station (ISS), above identical all-sky cameras at two observation sites about 25 km apart in Athabasca, Canada. The two sites are Athabasca University Geophysical Observatory (AUGO, 54.71N and 113.31W) and Athabasca University Geospace Observatory (AUGSO, 54.60N and 113.64W), and both cameras are equipped with filters to select N₂⁺ emission at 427.8 nm. To estimate the emission altitude, we applied two different methods to analyze coincident auroral images with overlapping fields of view. In the first method, images are mapped onto a horizontal plane by assuming an emission altitude to find the maximum correlations (Kataoka et al., AnnGeo, 2013). In the second method, images are mapped onto the Earth’s magnetic field lines (Whiter et al., Geosci, 2013). Observations have been made since August 30, 2024. We report the latest results of the comparison of the two methods of auroral altitude estimation based on the data obtained from September, 2024 to May, 2025.