The Evolution of Complex <i>E</i>_<i>s</i> Observed by Multi Instruments Over Low‐Latitude China

Abstract

Abstract A complex daytime sporadic E ( E s ) case with extremely high critical frequency ( f o E s ) was observed over the low latitude of China on 19 May 2018. Simultaneous observational results from two very high frequency (VHF) radars, two ionosondes, and multiple Global Navigation Satellite System total electron content and scintillation receivers are analyzed to investigate the evolution of the complex E s occurrence, which consisted of a relatively weak ambient E s layer ( f o E s &lt; 8 MHz) and band‐like strong E s structures ( f o E s &gt; 17 MHz) drifting from higher latitude. The strong E s structures elongated more than 500 km in the northwest‐southeast direction, drifted southwestward at a speed of ~65 m/s. VHF radar backscatter echoes were generated when the strong E s structures passed the radar field of view, with different echo patterns due to different radar and antenna configurations. No VHF radar backscatter echo was associated with the ambient E s layer. The mechanisms responsible for the formations of the ambient E s layer and band‐like strong E s structures are addressed and discussed.