Kilometer scale kinetic energy perturbations in the mesosphere derived from EISCAT velocity data


  • C. M. Hall


Traditionally, radar instruments which obtain coherent echoes from structures delineated by sharp gradients in refractive index have been used as a means of determining parameters describing neutral turbulence in the middle atmosphere. In these cases the very characteristics of the coherent signals are used. An alternative, somewhat akin to using velocity estimations from meteor trails and trails of artificially introduced racers, is to determine the kinetic energy perturbation from the velocity profiles alone, the latter being available from incoherent scatter radar. Here we describe a method which assumes that the velocity fluctuations are caused by perturbations of a 1-km scale, in the buoyancy subrange, but which still may be indicative of energy flux at the outer scale, illustrated by the remarkable similarity to energy dissipation rates determined by other measurements.