RÉSUMÉ

It was experimentally found that almost in half of cases of atmospheric front (AF) passages quasi-periodic changes in height and time variations of amplitudes of the partially reflected (PR) signals and radio noise as well as electron concentration in the D-region took place for tens of minutes due to the passage of infrasonic waves unlike during the periods before and after the passage. It was also determined that in the lower part of the mid-latitude D-region (heights of z < 80 km) the values of electron concentration appeared to be underestimated by a factor of 1.2...2.2 times as compared to control days. The mechanism of such an drop in magnitude N(z,t) can be explained by the effect of the tropospheric disturbance with the help of a complicated series performed both via the dynamic channel and via the channel of small components redistribution.