Numerical Studies of HF Doppler Variations Caused by Ionospheric Disturbances

Abstract

HF Doppler variations caused by ionospheric disturbances are studied using an ionosphere model containing sinusoidal traveling electron density fluctuations. The present study is different from earlier works in that we use a more realistic ionosphere model and a more accurate numerical method than previous works using corrugated specular reflector models. Our study gives a clue to estimate the TID-associated fluctuations of Ionospheric electron density by means of HF Doppler measurements. It is shown that some kinds of characteristic HF Doppler traces result depending on the wavelength of the disturbance and its traveling direction. Numerical results suggest that more or less 5% of the background electron density can explain most of the quasi-periodic variations on the observed HF Doppler records.