HF Doppler observations of nighttime F-region over Nagpur: Preliminary results

Abstract

A HF Doppler radar operating at 5.5 MHz has been developed for phase path measurements and regular nighttime observations have been made over Nagpur since October 1992. Data for the period October 1992-August 1993 have been analyzed for vertical drift velocities. Vertical velocity ranges from 0 to 26 m/s with a mean value of about 8 m/s during equinoxes and about 6 m/s during solstices. The post-sunset upward velocity is maximum during equinoxes and is related to the ExB drift. Premidnight upward drift is maximum during summer months and is associated with the neutral winds. The data are in fair agreement with those obtained at Waltair except for the movement related to the electrodynamic effect which is much stronger at Waltair.