Spectral composition of the water vapour self-continuum absorption within 2.7 and 6.25 µm bands

2019 ◽  
Vol 228 ◽  
pp. 97-105 ◽  
Author(s):  
Igor V. Ptashnik ◽  
Tatyana E. Klimeshina ◽  
Alexander A. Solodov ◽  
Andrey A. Vigasin
Keyword(s):  
Water Vapour ◽  
Spectral Composition ◽  
Continuum Absorption

scholarly journals Development and recent evaluation of the MT_CKD model of continuum absorption

2012 ◽  
Vol 370 (1968) ◽  
pp. 2520-2556 ◽  
Author(s):  
Eli J. Mlawer ◽  
Vivienne H. Payne ◽  
Jean-Luc Moncet ◽  
Jennifer S. Delamere ◽  
Matthew J. Alvarado ◽  
...  
Keyword(s):  
Water Vapour ◽  
Line Shape ◽  
Mathematical Formulation ◽  
Field Measurements ◽  
Continuum Absorption ◽  
Semi Empirical ◽  
Vapour Molecule ◽  
Primary Agent ◽  
The Continuum

Water vapour continuum absorption is an important contributor to the Earth's radiative cooling and energy balance. Here, we describe the development and status of the MT_CKD (MlawerTobinCloughKneizysDavies) water vapour continuum absorption model. The perspective adopted in developing the MT_CKD model has been to constrain the model so that it is consistent with quality analyses of spectral atmospheric and laboratory measurements of the foreign and self continuum. For field measurements, only cases for which the characterization of the atmospheric state has been highly scrutinized have been used. Continuum coefficients in spectral regions that have not been subject to compelling analyses are determined by a mathematical formulation of the spectral shape associated with each water vapour monomer line. This formulation, which is based on continuum values in spectral regions in which the coefficients are well constrained by measurements, is applied consistently to all water vapour monomer lines from the microwave to the visible. The results are summed-up (separately for the foreign and self) to obtain continuum coefficients from 0 to 20 000 cm −1 . For each water vapour line, the MT_CKD line shape formulation consists of two components: exponentially decaying far wings of the line plus a contribution from a water vapour molecule undergoing a weak interaction with a second molecule. In the MT_CKD model, the first component is the primary agent for the continuum between water vapour bands, while the second component is responsible for the majority of the continuum within water vapour bands. The MT_CKD model should be regarded as a semi-empirical model with strong constraints provided by the known physics. Keeping the MT_CKD continuum consistent with current observational studies necessitates periodic updates to the water vapour continuum coefficients. In addition to providing details on the MT_CKD line shape formulation, we describe the most recent update to the model, MT_CKD_2.5, which is based on an analysis of satellite- and ground-based observations from 2385 to 2600 cm −1 (approx. 4 μm).

scholarly journals Application of φ-IASI to IASI: retrieval products evaluation and radiative transfer consistency

2009 ◽  
Vol 9 (22) ◽  
pp. 8771-8783 ◽  
Author(s):  
G. Masiello ◽  
C. Serio ◽  
A. Carissimo ◽  
G. Grieco ◽  
M. Matricardi
Keyword(s):  
Water Vapour ◽  
Forward Model ◽  
Continuum Absorption ◽  
Weather Forecasts ◽  
Time Profiles ◽  
Spectral Residual ◽  
Atmospheric Sounding ◽  
Medium Range ◽  
Temperature Water

Abstract. Retrieval products for temperature, water vapour and ozone have been obtained from spectral radiances measured by the Infrared Atmospheric Sounding Interferometer flying onboard the first European Meteorological Operational satellite. These products have been used to check the consistency of the forward model and its accuracy and the expected retrieval performance. The study has been carried out using a research-oriented forward-inverse methodology, called φ-IASI, that the authors have specifically developed for the new sounding interferometer. The performance of the forward-inversion strategy has been assessed by comparing the retrieved profiles to profiles of temperature, water vapour and ozone obtained by co-locating in space and time profiles from radiosonde observations and from the European Centre for Medium-Range Weather Forecasts analysis. Spectral residuals have also been computed and analyzed to assess the quality of the forward model. Two versions of the high-resolution transmission molecular absorption database have been used, which mostly differ for ozone absorption line parameters, line and continuum absorption of both CO2 and H2O molecules. Their performance has been assessed by inter-comparing the results, and a consistent improvement in the spectral residual has been found when using the most updated release.

scholarly journals Airborne and satellite remote sensing of the mid-infrared water vapour continuum

2012 ◽  
Vol 370 (1968) ◽  
pp. 2611-2636 ◽  
Author(s):  
Stuart M. Newman ◽  
Paul D. Green ◽  
Igor V. Ptashnik ◽  
Tom D. Gardiner ◽  
Marc D. Coleman ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Vapour ◽  
Weather Forecasting ◽  
Field Measurements ◽  
Atmospheric Models ◽  
Atmospheric Measurements ◽  
Continuum Absorption ◽  
Infrared Radiance ◽  
Research Aircraft ◽  
Absorption Field

Remote sensing of the atmosphere from space plays an increasingly important role in weather forecasting. Exploiting observations from the latest generation of weather satellites relies on an accurate knowledge of fundamental spectroscopy, including the water vapour continuum absorption. Field campaigns involving the Facility for Airborne Atmospheric Measurements research aircraft have collected a comprehensive dataset, comprising remotely sensed infrared radiance observations collocated with accurate measurements of the temperature and humidity structure of the atmosphere. These field measurements have been used to validate the strength of the infrared water vapour continuum in comparison with the latest laboratory measurements. The recent substantial changes to self-continuum coefficients in the widely used MT_CKD (Mlawer–Tobin–Clough–Kneizys–Davies) model between 2400 and 3200 cm −1 are shown to be appropriate and in agreement with field measurements. Results for the foreign continuum in the 1300–2000 cm −1 band suggest a weak temperature dependence that is not currently included in atmospheric models. A one-dimensional variational retrieval experiment is performed that shows a small positive benefit from using new laboratory-derived continuum coefficients for humidity retrievals.

Water vapour line and continuum absorption in the thermal infrared—reconciling models and observations

2003 ◽  
Vol 129 (594) ◽  
pp. 2949-2969 ◽  
Author(s):  
Jonathan P. Taylor ◽  
Stuart M. Newman ◽  
Tim J. Hewison ◽  
Andrew McGrath
Keyword(s):  
Water Vapour ◽  
Thermal Infrared ◽  
Continuum Absorption
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