Intense daytime radio wave scintillations and sporadic E layer near the dip equator

Abstract

The paper describes two cases of very intense scintillation activity (amplitude exceeding 10 dB) recorded at Huancayo during the daytime on radio beacons on 257 MHz from Marisat satellite and ATS 3 (137 MHz) and LES 6 (254 MHz) signals. Both these events are shown to be associated with an intense blanketing equatorial sporadic E layer at Huancayo. It is suggested that the bursts of strong daytime scintillations of VHF radio waves are due to densely ionized thin sheets of ionization over the equator and only normally weak (≈1 dB) daytime scintillations may be due to instabilities associated with the q type of equatorial E_s.