17:15 〜 19:15
[PEM14-P17] Recalibration of ionogram virtual height and scaled parameters obtained by NICT's ionosonde observation
キーワード：イオノゾンデ、再校正、見かけ高度
Ionosonde observation system operated by National Institute of Information and Communications technology (NICT) was replaced to Vertical Incidence Pulsed Ionospheric Radar 2 (VIPIR2) in 2016 and 2017. At the beginning of the replacement, a calibration was done for the ionograms and range bias of 300 μsec has been removed. NICT has been sharing the range adjusted ionograms since then. On the other hand, Teraoka et al (2022 JpGU, 2023 SGEPSS) pointed out that virtual heights of sporadic E-lay (h’Es) decreased around 2017 when the new ionosonde was installed based on an analysis of the manual scaled parameters. The initial range calibration may not be sufficient. Therefore, adjustment was performed again, and the result will be reported in this presentation. We conducted an analysis of the calibration signal and typical ionospheric echo. The result shows that the virtual height was lower by about 24 km. It is also necessary to recalibrate manually and automatically scaled parameters. The recalibration is conducted for all ionograms and scaled parameters. The revised products are open through web page (https://wdc.nict.go.jp/Ionosphere/) since March 2025.