Study on the Simulation of Atmospheric Infrared Spectra PDF Download

Author: Thomas von Clarmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 648

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Author: Dominik Marx
Publisher: Cambridge University Press
ISBN: 1139477196
Category : Science
Languages : en
Pages : 503

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Book Description
Ab initio molecular dynamics revolutionized the field of realistic computer simulation of complex molecular systems and processes, including chemical reactions, by unifying molecular dynamics and electronic structure theory. This book provides the first coherent presentation of this rapidly growing field, covering a vast range of methods and their applications, from basic theory to advanced methods. This fascinating text for graduate students and researchers contains systematic derivations of various ab initio molecular dynamics techniques to enable readers to understand and assess the merits and drawbacks of commonly used methods. It also discusses the special features of the widely used Car–Parrinello approach, correcting various misconceptions currently found in research literature. The book contains pseudo-code and program layout for typical plane wave electronic structure codes, allowing newcomers to the field to understand commonly used program packages and enabling developers to improve and add new features in their code.

Author: Alain Chedin
Publisher: Springer Science & Business Media
ISBN: 3642845991
Category : Science
Languages : en
Pages : 484

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Book Description
One of major challenges facing Earth's science in the next decade and beyondis the development of an accurate long term observational data set to study global change. To accomplish this, a wide range of observations will be required to provide both new measurements, not previously achievable and measurements with a greater degreee of accuracy and resolution than the ones which are presently and currently available. Among the parameters that are currently retrieved from satellite vertical sounding observations, temperature and moisture profiles are the most important for the description of the thermodynamic state of the medium. Other parameters, like those describing the cloud fields, the surface state or the conditions close to the surface are also key parameters for meteorology and climatology. A new generation of high spectral atmospheric sounders in the infrared has recently been designed to provide both new and more accurate data about the atmosphere, land and oceans for application to climate studies. Among the important observations that these instruments should contribute to the climate data set are day and night global measurements of: atmospheric temperature profiles; relative humidity profiles; cloud field parameters; total ozone burden of the atmosphere; distribution of minor atmospehric gases (methane, carbonmonoxide and nitrous oxide).

Author: C. H. Douglass
Publisher:
ISBN:
Category :
Languages : en
Pages : 88

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Programs have been developed to simulate absorption and emission spectra of atmospheric and combustion product species. The programs use tabulated constants of the molecules have been included. The calculated emission and absorption spectra can be compared to experimental spectra and can be used to predict spectral shifts due to isotopic substitution. Results for a variety of materials and conditions are presented. Keywords: Spectral simulation, Emission spectra, Absorption spectra.

Author: Aaron Goldman
Publisher: CRC Press
ISBN: 1351363050
Category : Science
Languages : en
Pages : 266

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Book Description
The handbook presents spectra to be utilized for the detection and measurement of new constituents in the earth's atmosphere and to obtain data for common minor species with large gas amounts in the absorption cell (such as CH/sub 4/ and N/sub 2/O). These results can be applied in the identification of absorption features in atmospheric spectra determined over long atmospheric paths. The spectra were recorded with Fourier Transform Spectrometers which are more precise than grating spectrometers. Each molecule spectrum was plotted on two scales: a condensed scale covering the range from 75 to 300/cm in one frame, and an expanded view covering 20 or 10/cm per frame. Each plot contains the name of the molecule, chemical formula, the gas pressure, cell length, and estimated resolution of the spectrum.

Author: Maziar Bani Shahabadi
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
"The thermal infrared radiation has rich information content about surface properties, atmospheric gas composition and temperature profiling. Meteorological satellites and ground instruments are used to monitor upwelling and downwelling radiances, respectively. This study provides new analysis methodologies in different applications of hyperspectral infrared data in climate and weather monitoring. In the first study, an airborne spectrometer flying at tropopause level is proposed for stratospheric H2O sounding derived from downwelling radiances. A motivation is that variations of stratospheric water vapor impact significantly on the surface radiation budget. The advantage of using an airborne spectrometer is its ability to capture the small-scale H2O variability. A Line-By-Line radiative transfer model (LBLRTM) and Gauss-Newton iterative techniques are used to construct the retrieval algorithm. Our simulation experiments show that a spectrometer with 700-2000 cm-1 spectral coverage, 1 cm-1 spectral resolution, 10 s observation time, 12 cm aperture diameter, and realistic noise levels across different bands can reach a retrieval accuracy of 0.5 ppmv and 1 K for simultaneous retrieval of H2O and temperature in the lower to middle stratosphere. We also find that far infrared ( 700 cm-1) spectral measurements, because of their significantly higher noise level, provide little additional benefit for this application. In the second study, application of hyper-spectral radiance data for climate feedback analysis is discussed. Using General Circulation Model (GCM) profiles as input to the Moderate resolution atmospheric Transmission (MODTRAN) radiation code, spectral water vapor sensitivity Jacobians are developed to study the impact of water vapor on the Outgoing Longwave Radiation (OLR). It is shown that OLR changes linearly with water vapor change in the atmospheric window (800-1250 cm-1) and logarithmically in the water vapor absorption bands (the rotational band: 0-560 cm-1 and the vibrational-rotational band 1250-1850 cm-1). Using a Line-By-Line Radiative Transfer Model, LBLRTM, we develop second order H2O Jacobians and show that these terms provide a more accurate estimate of the sensitivity of the absorption to H2O perturbations in a given atmospheric layer. Based on these findings, to diagnose the water vapor radiative effect, we propose to rely on hybrid H2O scaling, i.e. linearly in window, and logarithmically in water vapor bands. In the third study, observed infrared radiance data are used to validate forecasts in range 0-24 h in radiance space. We adapt for cloudy sky computations a fast radiative transfer model commonly used at weather centers, RTTOV (Radiative Transfer for Television Operational Vertical Sounder), to generate synthetic radiance spectra from the output of a weather forecast model: the Global Environmental Multiscale (GEM) model. Synthetic radiance spectra are compared against Atmospheric Infrared Sounder (AIRS) observed radiance data. Novel in this study, spectral Jacobians of surface temperature, atmospheric temperature, and water vapor, obtained by prescribing unperturbed and perturbed profiles, are used for diagnosing the biases in GEM. Clear-sky diagnosis provides a test of radiation closure, in which we find radiance biases of GEM can be well explained by geophysical variable biases, such as surface temperature, and temperature and water vapor profiles. Cloud-related radiance biases are then further determined in all-sky conditions. Based on this spectral analysis, the following prominent GEM biases were identified: 1) too low (often 5 K) surface temperature over land, notably in daytime; 2) too high upper tropospheric humidity in the subtropical region (equivalent to a negative bias of 3 K in brightness temperature units); 3) a deficit of high clouds in western Pacific ocean Intertropical Convective Zone." --

Author: Roger L. Weichel
Publisher:
ISBN:
Category : Atmospheric temperature
Languages : en
Pages : 76

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Book Description
This report describes implementation and characteristics of two software systems, the Statistical Method of Parameter Estimation (Environmental Research and Technology, Inc.) and the Minimum Information Method (Air Force Global Weather Central). These systems are designed for investigating the retrieval of atmospheric temperature profiles from remotely sensed radiometric data. Significant features of the programs are discussed and preliminary results for simulated infrared, microwave, and combined infrared-microwave measurements are presented for the statistical method. Further development is suggested and approaches to optimum use of combined infrared-microwave measurements are outlined. Additionally, two appendices are provided which summarize recent developments in a variational-iterative computation scheme for radiative transfer calculations which included scattering effects of clouds and precipitation, and the use of near IR measurements for cloud-snow discrimination. Both developments have great potential in investigating remote sensing techniques. (Author).

Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781724010292
Category : Science
Languages : en
Pages : 28

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The Langley-D.U. collaboration on the analysis of high resolution infrared atmospheric spectra covered a number of important studies of trace gases identification and quantification from field spectra, and spectral line parameters analysis. The collaborative work included: Quantification and monitoring of trace gases from ground-based spectra available from various locations and seasons and from balloon flights. Studies toward identification and quantification of isotopic species, mostly oxygen and Sulfur isotopes. Search for new species on the available spectra. Update of spectroscopic line parameters, by combining laboratory and atmospheric spectra with theoretical spectroscopy methods. Study of trends of atmosphere trace constituents. Algorithms developments, retrievals intercomparisons and automatization of the analysis of NDSC spectra, for both column amounts and vertical profiles. Goldman, Aaron Langley Research Center

Author: Clifford Dalton Kern
Publisher:
ISBN:
Category : Earth temperature
Languages : en
Pages : 118

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Book Description
Of prime interest are the radiation data from that portion of the infrared spectrum known as the atmospheric water-vapor window, ranging from about 8 to 12 microns. Infrared signals received by weather satellites and aircraft depend, in clear air, on surface temperature, atmospheric interference and surface emissivity. For the latter, very different data in literature are found for clouds, water, rocks, etc. In this report correct emissivity data were sought in three ways: (1) Reflectivity of polished rock samples was tested in an infrared spectrograph for 5-16 microns wavelength. Using Kirchhoff's law this method yielded emissivities for near normal incidence. (2) Using an 8-13 microns sensitive radiometer and an aggregate, called emissivity box, the emissivity of many surfaces was measured directly. (3) A summer noon time flight of Tiros over the Mediterranean and the Sahara was evaluated.

Author: Mark John William McPhail
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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