Fast Thermal Radiative Transfer Model Distribution
RTSPEC is a rapid plane-parallel unpolarized radiative transfer model
for calculating upwelling radiance spectra from a thermally emitting
atmosphere. It implements the Deeter and Evans (1998) hybrid Eddington
approximation/single scattering approximate radiative transfer solution.
It assumes that the only scattering portion of the atmosphere is a
multiple layer cloud. The calculated spectrum is averaged with a
rectangular or triangular bandpass or convolved using a rectangular,
triangular, or sinc^2 FFT window, to produce the output spectrum.
Multiple spectral segments or channels may be output.
The model is written in a variant of Fortran77 and comes with a Unix
example script and sample input files.
Download the compressed tar
The README file shows the contents of the
The RTSPEC source file contains
documentation of the model.
February 5, 2001
Bug fix: Very rarely the Eddington and Hybrid single layer solution
routines (EDDSCATRT and SEDDSCATRT) would give bad (e.g. negative
radiances) due to the Planck slope parameter (beta) being close to the
Eddington eigenvalue (lambda). The check for this was not implemented
Changes were also made to the spectrum convolution routine.
December 15, 1999
Significant bug fix: downwelling radiances for mu<1 were in error due to
incorrect linear Planck function integration across a layer. This could
even affect upwelling radiances slightly by reflection of downwelling
June 1, 1999
Major upgrade by Aaron Evans, including:
- Upward viewing geometry
- Added surface reflection
- Double sideband simulation
- Convolution with sinc or sinc squared
- More modular code
A paper describing the Eddington, single scattering, and hybrid methods
has been published in the Journal of Quantitative Spectroscopy and
Deeter, M. N. and K. F. Evans, 1998: A hybrid Eddington-single
scattering radiative transfer model for computing radiances from
thermally emitting atmospheres. J. Quant. Spectosc. Radiat. Transfer,
It is available here as a
compressed Postscript file.
Last modified: July 9, 2001
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