The water vapor self-continuum absorption in the infrared atmospheric windows: New laser measurements near 3.3 μm and 2.0 μm

摘要

The amplitude, the temperature dependence and the physical origin of the water vapor absorption continuum are a long standing issue in molecular spectroscopy with direct impact in atmospheric and planetary sciences. In the recent years, we have determined the self-continuum absorption of water vapor at different spectral points of the atmospheric windows at 4.0, 2.1, 1.6 and 1.25 μm, by highly sensitive cavity enhanced laser techniques. These accurate experimental constraints have been used to adjust the last version (V3.2) of the semi-empirical MT_CKD model (Mlawer–Tobin_Clough–Kneizys–Davies) widely incorporated in atmospheric radiative transfer codes. In the present work, the self-continuum cross-sections, CS, are newly determined at 3.3 μm (3007 cm) and 2.0 μm (5000 cm) by optical-feedback-cavity enhanced absorption spectroscopy (OFCEAS) and cavity ring-down spectroscopy (CRDS), respectively. These new data allow completing the spectral coverage of the 4.0 and 2.1 μm windows, respectively, and testing the recently released V3.2 version of the MT_CKD3 continuum. By complementing high temperature literature data to the present data, the temperature dependence of the self continuum is presented. Institute of Engineering Univ. Grenoble Alpes