[P-EM13] Study of coupling processes in solar-terrestrial system

[PEM13-05] Long-term statistical analysis of electron density observed by the MU radar and comparison with 3-D tomography with GPS-TEC

*Shuto Masuda¹, Tatsuhiro Yokoyama¹, Nicholas Ssessanga¹, Mamoru Yamamoto¹, Susumu Saito² (1.Research Institute for Sustainable Humanosphere, Kyoto University, 2.Electronic Navigation Research Institute, National Institute of Maritime, Port, and Aviation Technology)

The MU radar, located in Shigaraki-Cho, Koka City, Shiga Prefecture, is a large atmospheric radar designed to observe the middle and upper atmosphere, and has been observing the ionospheric F region as an Incoherent Scatter (IS) radar regularly since 1986. The IS radar emits radio waves into the upper atmosphere and is capable of estimating various physical quantities in the ionosphere that contribute to the intensity and spectrum of the scattered waves. Electron and ion temperatures, plasma drift velocities and echo power are regularly observed by the MU radar (http://www.rish.kyoto-u.ac.jp/mu/isdata/).
We focus on the echo power, that is, the electron density in this research. The peak echo power measured by the MU radar is calibrated as the electron density that corresponds to the foF2 values of Kokubunji ionosondes. Long-term statistical analysis is then conducted and compared with the IRI model. Meanwhile, 3-D ionospheric tomography by using GEONET GPS-TEC data is conducted and published by Electronic Navigation Research Institute (https://www.enri.go.jp/cnspub/tomo3/). The vertical electron density profiles near the MU radar reproduced by the 3-D tomography generally agree with those of the MU radar observation. However, the tomography results degrade when the peak electron density altitude is lower than 300 km.