|This work focusses on the impact of atmospheric terms and ionization variations on radar echoes in the mesosphere. The measurements are based on observations with the VHF radars (53.5 MHz) in Kühlungsborn (54°N) and Andenes (69°N). Radar echoes are modulated on the one hand by meridional wind variations induced by planetary waves and on the other hand by electron density variations due to solar impacts. In case of the winter echoes, turbulence in the neutral gas and enhanced ionization are essential for their generation. These results contribute to a knowledge expansion of the physics and chemistry in the mesosphere.