[M-TT37] 稠密多点GNSS観測が切り拓く地球科学の新展開

[MTT37-P08] Performance of Sporadic E layer imaging by the ultra-dense GNSS network as compared with the real-time product with GEONE

*斎藤 享¹、吉原 貴之¹ (1.国立研究開発法人海上・港湾・航空技術研究所電子航法研究所)

キーワード：電離圏、スポラディックE層、ROTIマッピング

The Sporadic E (Es) layer is an ionospheric layer which has very high density but is thin in altitude occurring in the E region. It has been well known that it can reflect radio waves with frequencies from HF to VHF bands to cause anomalous long-distance propagation. Recently, total electron content (TEC) data derived from GNSS networks have been used to image 2-D structures of the Es layer. The perturbation component of TEC (dTEC) and the rate-of-TEC index (ROTI) are often used to detect Es layers.
Electronic Navigation Research Institute has been operating real-time analysis of dTEC and ROTI by using data from 200 selected stations of GEONET (GNSS Earth Observation Network) operated by Geospatial Information Authority of Japan (GSI). Structures of Es layers can be captured by the real-time ROTI product.
Recently, data from GNSS reference station network provided by SoftBank which consists of more than 3000 GNSS receivers are available. The extremely dense network enables to image the Es layer with finer resolution. In this study, ROTI maps with Es layer signatures of real-time product with GEONET 200 stations and SoftBank network with 3000+ stations are compared. Advantages of the denser Softbank network in studying the Es layer structures are discussed. Complementary use of GEONET real-time and SoftBank ROTI maps is also proposed.