ACCURATE LASER MEASUREMENTS OF THE WATER VAPOR SELF-CONTINUUM ABSORPTION IN FOUR NEAR INFRARED ATMOSPHERIC WINDOWS. A TEST OF THE MT_CKD MODEL.

2017 ◽  
Author(s):  
Alain Campargue ◽  
Semyon Vasilchenko ◽  
Loïc Lechevallier ◽  
Daniele Romanini ◽  
Didier Mondelain ◽  
...  
Keyword(s):  
Water Vapor ◽  
Near Infrared ◽  
Continuum Absorption ◽  
Laser Measurements ◽  
Atmospheric Windows

scholarly journals The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 3: Quantification of the mid- and near-infrared water vapor continuum in the 2500 to 7800 cm<sup>−1</sup> spectral range under atmospheric conditions

2016 ◽  
Vol 16 (18) ◽  
pp. 11671-11686 ◽  
Author(s):  
Andreas Reichert ◽  
Ralf Sussmann
Keyword(s):  
Water Vapor ◽  
Spectral Range ◽  
Near Infrared ◽  
Atmospheric Conditions ◽  
Water Vapor Absorption ◽  
Absorption Bands ◽  
Continuum Absorption ◽  
Upper Limits ◽  
Vapor Absorption ◽  
Spectral Ranges

Abstract. We present a first quantification of the near-infrared (NIR) water vapor continuum absorption from an atmospheric radiative closure experiment carried out at the Zugspitze (47.42° N, 10.98° E; 2964 m a.s.l.). Continuum quantification is achieved via radiative closure using radiometrically calibrated solar Fourier transform infrared (FTIR) absorption spectra covering the 2500 to 7800 cm−1 spectral range. The dry atmospheric conditions at the Zugspitze site (IWV 1.4 to 3.3 mm) enable continuum quantification even within water vapor absorption bands, while upper limits for continuum absorption can be provided in the centers of window regions. Throughout 75 % of the 2500 to 7800 cm−1 spectral range, the Zugspitze results agree within our estimated uncertainty with the widely used MT_CKD 2.5.2 model (Mlawer et al., 2012). In the wings of water vapor absorption bands, our measurements indicate about 2–5 times stronger continuum absorption than MT_CKD, namely in the 2800 to 3000 cm−1 and 4100 to 4200 cm−1 spectral ranges. The measurements are consistent with the laboratory measurements of Mondelain et al. (2015), which rely on cavity ring-down spectroscopy (CDRS), and the calorimetric–interferometric measurements of Bicknell et al. (2006). Compared to the recent FTIR laboratory studies of Ptashnik et al. (2012, 2013), our measurements are consistent within the estimated errors throughout most of the spectral range. However, in the wings of water vapor absorption bands our measurements indicate typically 2–3 times weaker continuum absorption under atmospheric conditions, namely in the 3200 to 3400, 4050 to 4200, and 6950 to 7050 cm−1 spectral regions.

scholarly journals The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared. Part III: Quantification of the near-infrared water vapor continuum under atmospheric conditions

2016 ◽  
Author(s):  
Andreas Reichert ◽  
Ralf Sussmann
Keyword(s):  
Water Vapor ◽  
Spectral Range ◽  
Near Infrared ◽  
Atmospheric Conditions ◽  
Water Vapor Absorption ◽  
Absorption Bands ◽  
Continuum Absorption ◽  
Upper Limits ◽  
Vapor Absorption ◽  
Spectral Ranges

Abstract. We present a first quantification of the near-infrared (NIR) water vapor continuum absorption from an atmospheric radiative closure experiment carried out at Mt. Zugspitze (47.42° N, 10.98° E, 2964 m a.s.l.). Continuum quantification is achieved via radiative closure using radiometrically calibrated solar FTIR absorption spectra covering the 2500 to 7800 cm−1 spectral range. The dry atmospheric conditions at the Zugspitze site (IWV 1.4 to 3.3 mm) enable continuum quantification even within water vapor absorption bands, while upper limits for continuum absorption can be provided in the centers of window regions. Throughout 75 % of the 2500 to 7800 cm−1 spectral range, the Zugspitze results are agree within our estimated uncertainty with the widely used MT_CKD 2.5.2-model (Mlawer et al., 2012). Notable exceptions are the 2800 to 3000 cm−1 and 4100 to 4200 cm−1 spectral ranges, where our measurements indicate about 5 times stronger continuum absorption than MT_CKD. The measurements are consistent with the laboratory measurements of Mondelain et al. (2015), which rely on cavity ring-down spectroscopy (CDRS), and the calorimetric-interferometric measurements of Bicknell et al. (2006). Compared to the recent FTIR laboratory studies of Ptashnik et al. (2012) and (2013), our measurements indicate 2–5 times weaker continuum absorption under atmospheric conditions in the wings of water vapor absorption bands, namely in the 3200 to 3400 cm−1, 4050 to 4200 cm−1, and 6950 to 7050 cm−1 spectral regions.

scholarly journals Water vapor self-continuum absorption in near-infrared windows derived from laboratory measurements

2011 ◽  
Vol 116 (D16) ◽  
Author(s):  
Igor V. Ptashnik ◽  
Robert A. McPheat ◽  
Keith P. Shine ◽  
Kevin M. Smith ◽  
R. Gary Williams
Keyword(s):  
Water Vapor ◽  
Near Infrared ◽  
Laboratory Measurements ◽  
Continuum Absorption

Water vapor continuum absorption in near-IR atmospheric windows

2015 ◽  
Vol 28 (2) ◽  
pp. 115-120 ◽  
Author(s):  
I. V. Ptashnik ◽  
T. M. Petrova ◽  
Yu. N. Ponomarev ◽  
A. A. Solodov ◽  
A. M. Solodov
Keyword(s):  
Water Vapor ◽  
Continuum Absorption ◽  
Near Ir ◽  
Atmospheric Windows

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

2017 ◽  
Author(s):  
Loic Lechevallier ◽  
Semen Vasilchenko ◽  
Roberto Grilli ◽  
Didier Mondelain ◽  
Daniele Romanini ◽  
...  
Keyword(s):  
Water Vapor ◽  
Temperature Dependence ◽  
Cross Sections ◽  
Optical Feedback ◽  
Molecular Spectroscopy ◽  
The Self ◽  
Water Vapor Absorption ◽  
Continuum Absorption ◽  
Enhanced Absorption ◽  
Atmospheric Windows

Abstract. 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−1) and 2.0 μm (5000 cm−1) 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. 1 Institute of Engineering Univ. Grenoble Alpes

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