First observations of type‐1 sporadic E Irregularities in the equatorial anomaly region using the Chung‐Li VHF radar

In this paper we present the characteristics of mid‐latitude irregularities first observed with the 52 MHz Chung‐Li radar. Intense type‐1 echoes with Doppler velocities of about 270 m/s (slightly smaller than the nominal ion‐acoustic wave speed of 360 m/s) in the height range from 103.1 km to 104.5 km lasted for about 2 minutes. The range‐time variations of sequential power spectra indicate that the patch of type‐1 irregularities moved toward the radar at a rate of about 42 m/s. The zonal drift motions of the type‐1 and type‐2 irregularities obtained from an interferometry technique showed that the irregularities drifted eastward with an average speed of 84 m/s.