Laboratory measurements of dry air atmospheric absorption with a millimeter wave cavity ringdown spectrometer

Abstract

Fast scan submillimeter spectroscopy (FASSST) cavity ring down spectroscopy has been used to measure the dry air continuum, and separately its individual component parts, at ∼6000 frequencies in the spectral region between 170 and 260 GHz. These measurements have been made at pressures that range from 0 to 3 atmospheres and in the temperature range between 230 and 320 K. For several of the components these are the first measurements made at or near atmospheric conditions. These measurements contain all of the information necessary to parameterize the observed absorptions in terms of the fundamental line and continuum interactions without the need to import external parameters. The inversion of this analysis makes possible the calculation of atmospheric absorption with meaningful uncertainties over this spectral region for temperatures and pressures of atmospheric interest.