Some main results of experimental investigations of the dynamical regime of the lower thermosphere over east Siberia (85--95 km) are presented. Regular measurements of horizontal ionospheric drifts by the radio-physical method of closely spaced receivers by using a long wavelength transmitter operating at a frequency of 200 kHz have been carried out near Irkutsk during 1975--1979. The seasonal and interannual variations of the prevailing wind (zonal and meridional), and amplitudes and phases of semidiurnal tides, are investigated. Planetary waves with periods of 1--30 days and internal gravity waves with periods of 20--80 min are found in the wind field. Comparison with results of analogous measurements in central Europe reveals a longitudinal effect on the dynamical regime of the mid-latitude lower thermosphere.