Co-ordinated thermospheric and F-region measurements from low latitudes

Abstract

Co-ordinated measurements of thermospheric temperatures by a ground-based Fabry-Perot spectrometer from Mt. Abu (24° 36'N, 72° 43'E geographic and 15° 22'N dip latitude) and F-region base height by ionosonde from Ahmedabad (23° N, 72° 6'E geographic and 13° 54'N dip latitude), reveal very close coupling to exist between them. There is a one-to-one correspondence between the neutral temperatures and the F-region base height, showing a relation of 11 ± 4 km/100 K. The behaviour agrees with that expected from the servo model of Rishbeth (1967, J. atmos. terr. Phys.29, 225). Results of two days of measurements during geomagnetically quiet periods, for which simultaneous data were available, are presented and the various related physical processes are discussed.