Effectiveness of brightness temperature ratios as indicators of atmospheric path conditions

Atmospheric attenuation is a quantity that may be derived by the scenario temperature under suitable hypotheses. A set of these temperatures, measured at different frequencies, allows to gain information about the amount of integrated water vapour and liquid content and the presence of clouds or precipitation in the atmosphere. In this framework the authors have focused their attention on the ratios between brightness temperatures, since these quantities are more suitable to point out the different atmospheric path condition than the temperatures themselves. Analysis on a daily basis as well as on a yearly basis of the ratios between the pair temperatures 30-20 GHz and 30-13 GHz have confirmed its use for the estimation of the atmospheric state