MILLIMETRIC FLUX DENSITIES AS A TEST OF ATMOSPHERIC-TURBULENCE

In this paper it is shown how submillimetre and millimetre flux density measurements of sky fluctuations can be used to infer the characteristics of atmospheric turbulence. Two different approaches have been followed: first, by considering the observed process as due to the atmospheric turbulence, we used the r.m.s. sky fluctuations to derive some physical parametres characterizing the phenomenon; second, by investigating the power spectrum and the autocorrelation function, we derive an empirical model (the AR model) to try to deduce the physical process. In this case, the fitted power spectrum agrees strikingly with that predicted by the theory of a stationary turbulent flow for the atmosphere in the sampled frequency range. This kind of modeling can help to disentangle the atmospheric fluctuations from the extraterrestrial signal in ground-based astrophysical measurements. Measurements of the water vapour content and atmospheric transmission at the Italian Base in Antarctica, where the data have been taken, at the wavelengths of 350 μm, 1 and 2mm are also reported. © 1990.