Infrared Water Vapor Continuum Absorption PDF Download

Author: Hugh R. Carlon
Publisher:
ISBN:
Category : Atmospheric electricity
Languages : en
Pages : 33

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Author: Hugh R. Carlon
Publisher:
ISBN:
Category : Atmospheric electricity
Languages : en
Pages : 0

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 29

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Book Description
We have carried out a detailed analysis of several long-path-length transmission measurements in the 8 to 12 micrometer atmospheric window in order to determine the extinction coefficient due to the water vapor continuum. Our results indicate that three modifications to the current LOWTRAN atmospheric transmission model are required. The first two corrections are an improved fit to the pure water vapor continuum absorption coefficient and the elimination of the atmospheric broadened continuum term. Finally, and most critically, a strong measured temperature dependence must be included in the water vapor continuum absorption coefficient. For path lengths ranging from 10 to 50 km, failure to incorporate these corrections can lead to errors in the computed transmission ranging from factors of 2 to more than 10,000.

Author: R. J. Nordstorm
Publisher:
ISBN:
Category :
Languages : en
Pages : 119

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Attenuation of infrared absorption in the troposphere is dominated by water vapor absorption. Most past work on the spectroscopy of water vapor has been on the analysis of the rotational and vibrational bands. Efforts to model the continuum absorption have not been as successful. It is demonstrated here that the far-wing phenomena is important in modeling the small but significant absorption in the continuum regions. (Author).

Author: Michael Eugene Thomas
Publisher:
ISBN:
Category : Infrared spectroscopy
Languages : en
Pages : 468

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Book Description
Attenuation of infrared radiation in the troposphere is dominated by water vapor absorption. Most past work on the spectroscopy of water vapor has been on the analysis of the rotational and vibrational bands. As a result a thorough listing of line positions, line strengths and halfwidths exists today. Because of the weak 'continuum' absorption in the water vapor windows centered at 10 and 4 microns, efforts to measure and model the continuum have not been as successful as efforts in the analysis of the bands. Yet a precise understanding of continuum absorption is important for long path energy transmission. The purpose of this study is to demonstrate the importance of far wing phenomena in characterizing H2O continuum absorption. A total line shape for water vapor-nitrogen interactions valid under tropospheric conditions is derived. The model is tested using a set of experimental room temperature H2O continuum measurements of high quality. Using this data base parameters of the far wing component of the total line shape are determined.

Author: Robert Paul D'Entremont
Publisher:
ISBN:
Category : Attenuation (Physics)
Languages : en
Pages : 50

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The Real-Time Nephanalysis (RTNE PH) generates real-time global analysis of cloud extent, base, height, and type. The RTNE PH makes extensive use of satellite data that are measured in the 10-12 micron infrared (IR) window for thermal mapping of clouds and the earth's surface both day and night. Water vapor absorption effects are significant in such data, especially for high viewing angles and tropical atmospheres where water vapor concentrations are generally high. Water vapor attenuates the emitted ground radiance, reducing its magnitude and with it the apparent temperature of the surface being viewed. Currently, the RTNEPH takes into account such attenuation losses using lookup tables that are functions of viewing geometry, time of day, type of background, and the like. However, these corrections have limited value and leave room for significant improvement. This report outlines and presents two new techniques that are expected to enhance the attenuation correction capabilities of the RTNEPH, multivariate polynomial regression (the Weinreb technique) and the correlated K method.

Author: Adarsh Deepak
Publisher: Elsevier
ISBN: 1483273342
Category : Science
Languages : en
Pages : 712

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Book Description
Atmospheric Water Vapor contains the technical proceedings of the International Workshop on Atmospheric Water Vapor held in Vail, Colorado, on September 11-13, 1979. The papers assess the state-of-the-art in measurement, modeling, and application of atmospheric water vapor properties and highlight important problems that require further effort in order to better understand the atmosphere itself as well as the electromagnetic propagation through the atmosphere. Comprised of 39 chapters, this book begins with a discussion on the optics and spectroscopy of water vapor. Some actual spectra showing the problems specific to the water molecule are described, along with the method used to calculate precise vibration-rotation energy levels and wave functions. Atmospheric infrared transmission measurements in maritime locations are also presented. Subsequent sections explore microwave and millimeter wave phenomena; geoastrophysical applications; and in situ measurements, remote sensing, and meteorology of water vapor. The final chapters deal with the microphysics and atmospheric chemistry of water vapor. This monograph will be of interest to scientists from universities, government agencies, research laboratories, and industry.

Author: Hugh R. Carlon
Publisher:
ISBN:
Category :
Languages : en
Pages : 45

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This report summarizes the results of a two-year study of atmospheric infrared 'continuum' absorption attributed to intermolecularly bonded clusters in water vapor. Spectral data are reviewed for water vapor, steam and liquid water. The infrared continuum absorption is discussed in detail and is shown to be explicable on the basis of homogeneous or ion-induced cluster distributions in water vapor, where the cluster population is approximately proportional to the square of the partial water vapor pressure. Thermodynamic consistency between the vapor and liquid phases is discussed for temperatures including the critical (374 C) where the phases become one. Simple oscillator models are shown to give agreement with observed spectral lines, suggesting certain cluster configurations. The ion concentration of moist air versus temperature is discussed, and measurements of ion cluster distributions are considered. Cluster absorption at longer wavelengths including the microwave region is discussed. Conclusions are presented.

Author: John Gerald Cormier
Publisher: National Library of Canada = Bibliothèque nationale du Canada
ISBN: 9780612690691
Category :
Languages : en
Pages : 226

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Author: R. F. Calfee
Publisher:
ISBN:
Category : Absorption spectra
Languages : en
Pages : 32

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Book Description
We report the quantitative absorption coefficients of water vapor in a format suitable for calculation of water vapor absorption spectra characterized by instrumental bandpasses of 1 cm−1 or greater in the 670 to 1450 cm−1 region. The coefficients are derived from individual line parameters of H2O and represent a useful way of reducing line parameter data to a practical volume of information for 1 cm−1 resolution spectra of the troposphere. Transmission spectra for three water vapor concentrations show typical applications of the absorption coefficient tables. The application of the data is restricted to conditions within 10% of 1 atmosphere pressure and a temperature of 296 K if a transmission accuracy of 2% is to be maintained.