Vertical Transport Coefficients in the Mesosphere Obtained from Radar Observations

Abstract

Incoherent scatter echoes from the mesosphere are interpreted in terms of isolated layers of mesospheric turbulence in the manner of Woodman and Guillen. The parameters describing such turbulent layers are evaluated and shown to be consistent with observations and calculations of eddy mixing and dissipation in the mesosphere, and vertical mixing by this process may make a substantial contribution to vertical mixing in this region of the atmosphere. Thew turbulent layers should have also produced partial reflections of a magnitude similar to those typically observed with that technique. It is thus suggested that incoherent scatter returns and partial reflections be used to evaluate the contribution of turbulent layers to eddy mixing in the mesosphere. An expression for the resulting time-averaged diffusion coefficient at mesospheric heights is presented as a function of the received power and correlation time obtained from incoherent scatter observations.