Fig. 6From: Simultaneous observations of equatorial plasma bubbles with an all-sky airglow imager and a HF Doppler sounding system in TaiwanEstimation of reflection altitude through comparison between reproduced and observed OSS traces. a Doppler spectrogram of Event 3 where the Doppler shifts, estimated by assuming the reflection altitude at 300 km, are overplotted. b The same Doppler spectrogram as (a) but with the Doppler shifts estimated by assuming the reflection altitude of 150 kmBack to article page