On the linkage of daytime 150 km echoes and abnormal intermediate layer traces over Sanya

摘要: [1] The daytime 150 km echoes, which are associated with the upper E region field-aligned irregularities, have been observed around equatorial electrojet but never before at magnetic latitudes near northern anomaly crest region. We present first results of echo over Sanya, China, a station located far away from dip equator in Northern Hemisphere. A layer weak radar echoes spectral width less than 10 m s−1 was seen height range 145 km 12:15 LT to 152 km 13:45 on 21 July 2010. The interesting aspect is that rare observation small Sanya VHF preceded by occurrence an unusual intermediate layer, identified as abnormal traces corresponding ionograms. possible gravity wave activity (that implicates presence density gradients) could make significant contribution growth irregularities responsible for rarely detected Sanya.