In situ measurements of turbulent energy dissipation rates and eddy diffusion coefficients during MAP/WINE

Abstract

In situ measurements of turbulent energy dissipation rates 6 and eddy diffusion coefficients in the 65-120 km altitude range using mass spectrometers, positive ion probes and foil clouds are presented. The mass spectrometer and the ion probe data were both analyzed with two independent theoretical approaches to derive ε. In general, the derived quantities agree with the values discussed in the literature, although noticeable differences occur in certain rocket flights. An intercomparison of the spectral power densities derived from the observed neutral gas and positive ion density fluctuations supports the assumption that under certain circumstances positive ions can be used as passive tracers for neutral gas number density fluctuations. The observed ε profiles exhibit a local minimum around 80 km altitude. © 1987.