Atmospheric radiative transfer codes

About: Atmospheric radiative transfer codes is a research topic. Over the lifetime, 6011 publications have been published within this topic receiving 176317 citations.

Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave

Abstract: A rapid and accurate radiative transfer model (RRTM) for climate applications has been developed and the results extensively evaluated. The current version of RRTM calculates fluxes and cooling rates for the longwave spectral region (10–3000 cm−1) for an arbitrary clear atmosphere. The molecular species treated in the model are water vapor, carbon dioxide, ozone, methane, nitrous oxide, and the common halocarbons. The radiative transfer in RRTM is performed using the correlated-k method: the k distributions are attained directly from the LBLRTM line-by-line model, which connects the absorption coefficients used by RRTM to high-resolution radiance validations done with observations. Refined methods have been developed for treating bands containing gases with overlapping absorption, for the determination of values of the Planck function appropriate for use in the correlated-k approach, and for the inclusion of minor absorbing species in a band. The flux and cooling rate results of RRTM are linked to measurement through the use of LBLRTM, which has been substantially validated with observations. Validations of RRTM using LBLRTM have been performed for the midlatitude summer, tropical, midlatitude winter, subarctic winter, and four atmospheres from the Spectral Radiance Experiment campaign. On the basis of these validations the longwave accuracy of RRTM for any atmosphere is as follows: 0.6 W m−2 (relative to LBLRTM) for net flux in each band at all altitudes, with a total (10–3000 cm−1) error of less than 1.0 W m−2 at any altitude; 0.07 K d−1 for total cooling rate error in the troposphere and lower stratosphere, and 0.75 K d−1 in the upper stratosphere and above. Other comparisons have been performed on RRTM using LBLRTM to gauge its sensitivity to changes in the abundance of specific species, including the halocarbons and carbon dioxide. The radiative forcing due to doubling the concentration of carbon dioxide is attained with an accuracy of 0.24 W m−2, an error of less than 5%. The speed of execution of RRTM compares favorably with that of other rapid radiation models, indicating that the model is suitable for use in general circulation models.

Thermal Radiation Heat Transfer

Abstract: A comprehensive discussion of heat transfer by thermal radiation is presented, including the radiative behavior of materials, radiation between surfaces, and gas radiation. Among the topics considered are property prediction by electromagnetic theory, the observed properties of solid materials, radiation in the presence of other modes of energy transfer, the equations of transfer for an absorbing-emitting gas, and radiative transfer in scattering and absorbing media. Also considered are radiation exchange between black isothermal surfaces, radiation exchange in enclosures composed of diffuse gray surfaces and in enclosures having some specularly reflecting surfaces, and radiation exchange between nondiffuse nongray surfaces. The use of the Monte Carlo technique in solving radiant-exchange problems and problems of radiative transfer through absorbing-emitting media is explained.

Radiative heat transfer

Abstract: 1. Fundamentals of Thermal Radiation 2. Radiative Property Predictions from Electromagnetic Wave Theory 3. Radiative Properties of Real Surfaces 4. View Factors 5. Radiative Exchange Between Gray, Diffuse Surfaces 6. Radiative Exchange Between Partially-Specular Gray Surfaces 7. Radiative Exchange Between Nonideal Surfaces 8. Surface Radiative Exchange in the Presence of Conduction and Convection 9. The Equation of Radiative Transfer in Participating Media 10. Radiative Properties of Molecular Gases 11. Radiative Properties of Particulate Media 12. Radiative Properties of Semitransparent Media 13. Exact Solutions for One-Dimensional Gray Media 14. Approximate Solution Methods for One-Dimensional Media 15. The Method of Spherical Harmonics (PN-Approximation) 16. The Method of Discrete Ordinates (SN-Approximation) 17. The Zonal Method 18. The Treatment of Collimated Irradiation 19. The Treatment of Nongray Extinction Coefficients 20. The Monte Carlo Method for Thermal Radiation 21. Radiation Combined with Conduction and Convection 22. Inverse Radiative Heat Transfer A. Constants and Conversion Factors B. Tables for Radiative Properties of Opaque Surfaces C. Blackbody Emissive Power Table D. View Factor Catalogue E. Exponential Integral Functions F. Computer Codes Author Index Subject Index

Radiative forcing by long‐lived greenhouse gases: Calculations with the AER radiative transfer models

Abstract: A primary component of the observed, recent climate change is the radiative forcing from increased concentrations of long-lived greenhouse gases (LLGHGs). Effective simulation of anthropogenic climate change by general circulation models (GCMs) is strongly dependent on the accurate representation of radiative processes associated with water vapor, ozone and LLGHGs. In the context of the increasing application of the Atmospheric and Environmental Research, Inc. (AER) radiation models within the GCM community, their capability to calculate longwave and shortwave radiative forcing for clear sky scenarios previously examined by the radiative transfer model intercomparison project (RTMIP) is presented. Forcing calculations with the AER line-by-line (LBL) models are very consistent with the RTMIP line-by-line results in the longwave and shortwave. The AER broadband models, in all but one case, calculate longwave forcings within a range of -0.20 to 0.23 W m{sup -2} of LBL calculations and shortwave forcings within a range of -0.16 to 0.38 W m{sup -2} of LBL results. These models also perform well at the surface, which RTMIP identified as a level at which GCM radiation models have particular difficulty reproducing LBL fluxes. Heating profile perturbations calculated by the broadband models generally reproduce high-resolution calculations within a few hundredths K d{sup -1} in the troposphere and within 0.15 K d{sup -1} in the peak stratospheric heating near 1 hPa. In most cases, the AER broadband models provide radiative forcing results that are in closer agreement with high 20 resolution calculations than the GCM radiation codes examined by RTMIP, which supports the application of the AER models to climate change research.

Light and Water: Radiative Transfer in Natural Waters

Abstract: Fundamentals: Radiometry. Photometry. Optical Properties of Water. Radiative Transfer: Across the Surface. Within the Water. Solutions Methods: Monte Carlo Methods. Invariant Imbedding Methods: Introduction. Invariant Imbedding Methods: Solving the RTE. Eigenmatrix Methods. Inverse Methods. Solutions: Underwater Light Fields. Epilogue. Chapter Problems. References.