Imprint of equatorial electrodynamical processes in the OI 630.0 nm dayglow

Results from coordinated measurements of OI 630.0 nm dayglow intensities (c entered on similar to 220 km altitude), along with VHF (50 MHz) coherent ba ckscatter returns from Thiruvananthapuram, a dip equatorial station in Indi a, revealed that the temporal variability at short periods (<4 h) of the Do ppler frequency of the coherently backscattered 50 MHz radar signal in the electrojet region (similar to 101 km altitude) preceded the dayglow variati ons. The time delay was found to be inversely related to the electric field magnitude inferred from the Doppler frequency and also with the independen tly estimated electrojet strength inferred from the ground magnetic data. T hese results are presented as direct evidence for the prevailing electrodyn amic coupling between the E- and F-region of the ionosphere over the dip eq uator. (C) 1999 Elsevier Science Ltd. All rights reserved.