Mesospheric turbulence parameters obtained from co-located VHF and MF radar observations during polar summer

Turbulence at mesosphere altitudes is observed by means of radar backscattering at two frequencies. The observations were conducted at the Andoya Island/North Norway during summer 2004. At VHF frequency turbulence parameters can only be observed in the presence of polar mesospheric summer echoes while at MF frequency mesospheric altitudes turbulence can be probed throughout the whole year. The turbulent energy dissipation rates estimated from Doppler spectral width measurements of the co-located radars are in general agreement. Additionally, we discuss observations of the aspect sensitivity which describe the anisotropy of the scattering entities. We show two typical observations with these radars where we could observe PMSE in one case and no PMSE in the other case.