Abstract

An extensive study of the atmospheric transmission at millimeter and submillimeter wavelengths has been performed since the early 1990s with a Fourier Transform Spectrometer (FTS) mounted on the Caltech Submillimeter Observatory (CSO) atop Mauna Kea (Hawaii), 4100 m above sea level. The goal of these observations is to compile a data base of accurately calibrated atmospheric transmission spectra for use in refining atmospheric models. In this context, the definition of the "quasi-continuum" opacity component is paramount. While our earlier work extending up to 1.0 THz has allowed the separation of the "wet" and "dry" quasi-continua components, with both shown to be following ν² laws in this regime, here we report on the extension of these observations to 1.6 THz. In the higher frequency regime, our preliminary results indicate that the ν² description may begin to fail due to proximity to the FIR band centers. Comparisons of our data below 1 THz with extant models give a remarkable agreement.

© 2005 Optical Society of America