On the Comparison of Turbulent Parameters and Eddy Coefficients in the Lower Thermosphere

Techniques to measure turbulence in the lower thermosphere are reviewed. The instantaneous properties of turbulence in the lower thermosphere (e.g., turbulent velocities and density fluctuations) can be measured in-situ by smoke trails, instrumented falling spheres, ion probes, and mass spectrometers. Information on turbulent processes may also be gained by studying the composition of the lower thermosphere. In contrast to density fluctuations, however, compositional profiles can provide quantitative information on only the long term average of turbulent activity. Compositional profiles are sensitive to the presence of vertical bulk motions.