NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Three Dimensional Atmospheric Radiative Transfer-Applications and Methods ComparisonWe review applications of 3D radiative transfer in the atmosphere, emphasizing the wide spectrum of scales important to remote sensing and modeling of cloud fields, and the characteristic scales introduced into observed radiances and fluxes by the distribution of photon pathlengths at conservative and absorbing wavelengths. We define the "plane-parallel bias", which is a measure of the importance of 3D cloud structure in large-scale models, and the "independent pixel errors" that quantify the significance of 3D effects in remote sensing, and emphasize their relative magnitude and scale dependence. A variety of approaches in current use in 3D radiative transfer, and issues of speed, accuracy, and flexibility are summarized. We also describe a recently initiated "International Intercomparison of 3-Dimensional Radiation Codes", or I3RC. I3RC is a 3-phase effort that has as its goals to: (1) understand the errors and limits of 3D methods; (2) provide "baseline" cases for future 3D code development; (3) promote sharing of 3D tools; (4) derive guidelines for 3D tool selection; and (5) improve atmospheric science education in 3D radiative transfer. Selected results from Phases 1 and 2 of I3RC are discussed. These are taken from five cloud fields: a 1D field of bar clouds, a 2D radar-derived field, a 3D Landsat-derived field, a stratiform cloud from the model of C. Moeng, and a convective cloud from the model of B. Stevens. Computations have been carried out for three monochromatic wavelengths (one conservative, one absorptive, and one thermal) and two solar zenith angles (0, 60 degrees).
Document ID
20020009012
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Cahalan, Robert F.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Einaudi, Franco
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Meteorology And Climatology
Meeting Information
Meeting: European Geophysical Society XXVI General Assembly
Location: Nice
Country: France
Start Date: March 25, 2001
End Date: March 30, 2001
Sponsors: European Geophysical Society
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available