The main results of the long-term measurements of the neutral atmosphere parameters by the artificial periodic irregularities techniques

The results of the atmospheric parameter determination by the method of artificial periodic irregularities (the API techniques) at the E-region heights obtained during many years of the observation are presented. The features of the obtaining data, their processing and the determination of the atmospheric parameters are given in details. A lot of information about dynamical phenomena in the lower thermosphere has been obtained. There are often height profiles of the atmospheric parameters with the wave-like variations and with the vertical scale of about 4-6 km. The temporal variations of the atmospheric parameters take place with the periods from 15 min to some hours. Such variations could be caused by the passage of the internal gravity waves (IGWs) and the tide waves. The temperature minima were observed as 100-140 K above 100 km in the equinoctial periods. The instability growth is also observed in the number of cases. The dependence of the neutral temperature and the density on solar and geomagnetic activity is not found.