Effect of meteor trail ionization on ionospheric propagation of radio signals

It has been observed that radio signals in the LF band are absorbed while that at the HF band is enhanced. The patterns of signal strength variations in the two bands appear to be complementary to each other. The results of analysis of the data obtained in Calcutta for a 1-yr period are critically examined in relation to the probable mechanisms of dissipation of the trail. It has been suggested that the dissipation is governed mainly by the ambipolar and turbulent diffusion and attachment. A theoretical curve of the variation of critical trail radius in the LF band based on this suggestion is in fairly good agreement with the nature of the effects. The diurnal and seasonal variation of meteor rates is found to be in good agreement with that obtained by other methods, although the rate is lower.