Estimation of Drift of Equatorial Ionoshere of Post Sunset-Sector by Means of Low Frequency Spaceborne SAR

Abstract

Recent studies indicate the potential of low frequency space-borne SAR sensors to monitor and quantify structure and dynamics of ionosphere [1-3]. At the post-sunset sector of the equatorial ionosphere, the instability of the electron den-sity often induces plasma bubbles aligned to the geomagnet-ic field [4], whose effects are seen as distinctive stripe pat-terns on SAR data [5-6]. At the same time, the free-electrons in this sector of ionosphere drift eastward [7]. This paper explores this effect captured on ALOS and ALOS-2 SAR data to estimate the drift velocity and altitude of the bubbles [8]. Based on the azimuth sub-band of SAR data analysis the height and velocities are estimated, and compared to the measurements from ionosonde. The sensitivity of the esti-mates is analyzed, and finally a possible observation config-uration for further ionospheric study is proposed.