HF doppler measurement in the auroral ionosphere

HF doppler shift measurements were made at Rankin Inlet, N. W. T. in Canada for one winter month in 1980. It became clear that the trace features of the HF doppler frequency shift observed at Rankin Inlet are quite different from those observed in the middle latitudes. The shift is characterized by its diffuse appearance in an f-t diagram, and also by the existence of discrete line structures in the diffuse band. The lines are generally inclined to the time axis. An ionospheric model, which can explain this feature of the HF doppler shift at high latitudes, is presented in this paper. According to the model, the discrete line structure is thought to be a manifestation due to the signal being reflected from a moving irregularity in the ionosphere. Velocities were computed with parameters consistent with the data. The result shows that the velocities of irregularity range from 1 to 50m/s. These values of velocity could possibly be thought as a drift motion due to the electric field in the ionosphere. The corresponding electric field intensity is estimated at a few mV/m at the auroral ionospheric height, which is consistent with values obtained from the IS radar at Chatanika