講演情報
[PEM12-P18]Study of long-term variations in the sporadic E layer over Japan by using ionosonde observations
*寺岡 宙惟1、Liu Huixin1、西岡 未知2、木暮 優1 (1.九州大学、2.国立研究開発法人情報通信研究機構)
キーワード：
スポラディックE層
A sporadic E (Es) layer is one of the important ionospheric irregularities and disturbs wireless communications. In this study, We examine the long-term trend of Es density and occurrence by using long-term data of ionosonde observations at Japanese 4 stations, i.e., Wakkanai(45.16°N, 141.75°E, during 1948-2021), Kokubunji(35.71°N, 139.49°E, during 1957-2020), Yamagawa(31.20°N, 130.62°E, during1965-2020), Okinawa(26.68°N, 128.15°E, during972-2021). To derive their long-term trend, we apply a multiple regression method with the ionosonde data. The presentation focuses on variabilities of its occurrence frequency and intensity, and latitudinal dependence. We also show trend correlations with the background ionospheric E and F layers.