First CRDS-measurements of water vapour continuum in the 940 nm absorption band

Measurements of near-infrared water vapour continuum using continuous wave cavity ring down spectroscopy (cw-CRDS) have been performed at around 10611.6 and 10685.2 cm(-1). The continuum absorption coefficients for N2-broadening have been determined to be C-F(296K) =(1.0 +/- 0.2) x 10(-24) cm(2) mol(-1) atm(-1) and C-F(278K) = (1.8 +/- 0.4) x 10(-24) cm(2) mol(-1) atm(-1) at 10611.6 cm(-1), and C-F(296K) = (1.6 0.5) x 10(-24) cm(2) mol(-1) atm(-1) and C-F(278K) = (2.1 +/- 0.4) x 10(-24) cm(2) mol(-1) atm(-1) at 10685.2cm(-1), respectively. These results represent the first near-IR continuum laboratory data determined within the complex spectral environment in the 940 nm water vapour band and are in reasonable agreement with simulations using the semiempirical CKD formulation. (c) 2006 Elsevier Ltd. All rights reserved.