Daytime vertical and zonal velocities from 150‐km echoes: Their relevance to F‐region dynamics

Abstract

As it was suggested by Kudeki and Fawcett [1993], and later shown by Woodman and Villanueva [1995], vertical Doppler velocities of daytime 150‐km echoes represent the vertical E × B drift velocities at F region altitudes. Recently a special experiment was conducted to compare not only the vertical but also the zonal velocities from 150‐km echoes with those from an incoherent scatter radar (ISR) mode perpendicular to the magnetic field. The vertical velocity comparisons show that (1) there is a very good agreement between 150‐km velocity and the mean F‐region E × B drift, and (2) much better agreement is found with the extrapolated values from the ISR altitudinal profiles. On the other hand poor‐to‐good agreement is found between their zonal components. Our preliminary zonal velocity results, indicate that there is a poor agreement before noontime, while better agreement is found in the afternoon.