subroutine rrtmg_lw::setcoef ( real (kind=kind_phys), dimension(nlay), intent(in)  pavel, real (kind=kind_phys), dimension(nlay), intent(in)  tavel, real (kind=kind_phys), dimension(0:nlay), intent(in)  tz, real (kind=kind_phys), intent(in)  stemp, real (kind=kind_phys), dimension(nlay), intent(in)  h2ovmr, real (kind=kind_phys), dimension(nlay,maxgas), intent(in)  colamt, real (kind=kind_phys), dimension(nlay), intent(in)  coldry, real (kind=kind_phys), dimension(nlay), intent(in)  colbrd, integer, intent(in)  nlay, integer, intent(in)  nlp1, integer, intent(out)  laytrop, real (kind=kind_phys), dimension(nbands,0:nlay), intent(out)  pklay, real (kind=kind_phys), dimension(nbands,0:nlay), intent(out)  pklev, integer, dimension(nlay), intent(out)  jp, integer, dimension(nlay), intent(out)  jt, integer, dimension(nlay), intent(out)  jt1, real (kind=kind_phys), dimension(nlay,nrates,2), intent(out)  rfrate, real (kind=kind_phys), dimension(nlay), intent(out)  fac00, real (kind=kind_phys), dimension(nlay), intent(out)  fac01, real (kind=kind_phys), dimension(nlay), intent(out)  fac10, real (kind=kind_phys), dimension(nlay), intent(out)  fac11, real (kind=kind_phys), dimension(nlay), intent(out)  selffac, real (kind=kind_phys), dimension(nlay), intent(out)  selffrac, integer, dimension(nlay), intent(out)  indself, real (kind=kind_phys), dimension(nlay), intent(out)  forfac, real (kind=kind_phys), dimension(nlay), intent(out)  forfrac, integer, dimension(nlay), intent(out)  indfor, real (kind=kind_phys), dimension(nlay), intent(out)  minorfrac, real (kind=kind_phys), dimension(nlay), intent(out)  scaleminor, real (kind=kind_phys), dimension(nlay), intent(out)  scaleminorn2, integer, dimension(nlay), intent(out)  indminor  )

private

Parameters

pavel	layer pressure (mb)
tavel	layer temperature (K)
tz	level(interface) temperatures (K)
stemp	surface ground temperature (K)
h2ovmr	layer w.v. volumn mixing ratio (kg/kg)
colamt	column amounts of absorbing gases. 2nd indices range: 1-maxgas, for watervapor,carbon dioxide, ozone, nitrous oxide, methane,oxigen, carbon monoxide,etc. \((mol/cm^2)\)
coldry	dry air column amount
colbrd	column amount of broadening gases
nlay	total number of vertical layers
nlp1	total number of vertical levels
laytrop	tropopause layer index (unitless)
pklay	integrated planck func at lay temp
pklev	integrated planck func at lev temp
jp	indices of lower reference pressure
jt,jt1	indices of lower reference temperatures
rfrate	ref ratios of binary species param (:,m,:)m=1-h2o/co2,2-h2o/o3,3-h2o/n2o, 4-h2o/ch4,5-n2o/co2,6-o3/co2 (:,:,n)n=1,2: the rates of ref press at the 2 sides of the layer
facij	factors multiply the reference ks, i,j=0/1 for lower/higher of the 2 appropriate temperatures and altitudes.
selffac	scale factor for w. v. self-continuum equals (w. v. density)/(atmospheric density at 296k and 1013 mb)
selffrac	factor for temperature interpolation of reference w. v. self-continuum data
indself	index of lower ref temp for selffac
forfac	scale factor for w. v. foreign-continuum
forfrac	factor for temperature interpolation of reference w.v. foreign-continuum data
indfor	index of lower ref temp for forfac
minorfrac	factor for minor gases
scaleminor,scaleminorn2	scale factors for minor gases
indminor	index of lower ref temp for minor gases

setcoef General Algorithm

1. Calculate information needed by the radiative transfer routine that is specific to this atmosphere, especially some of the coefficients and indices needed to compute the optical depths by interpolating data from stored reference atmospheres.
2. Calculate the integrated Planck functions for each band at the surface, level, and layer temperatures.
3. Find the two reference pressures on either side of the layer pressure. store them in jp and jp1. store in fp the fraction of the difference (in ln(pressure)) between these two values that the layer pressure lies.
4. Determine, for each reference pressure (jp and jp1), which reference temperature (these are different for each reference pressure) is nearest the layer temperature but does not exceed it. store these indices in jt and jt1, resp. store in ft (resp. ft1) the fraction of the way between jt (jt1) and the next highest reference temperature that the layer temperature falls.
5. We have now isolated the layer ln pressure and temperature, between two reference pressures and two reference temperatures (for each reference pressure). we multiply the pressure fraction fp with the appropriate temperature fractions to get the factors that will be needed for the interpolation that yields the optical depths (performed in routines taugbn for band n).
6. Set up factors needed to separately include the minor gases in the calculation of absorption coefficient.
7. If the pressure is less than ~100mb, perform a different set of species interpolations.
8. Set up factors needed to separately include the water vapor self-continuum in the calculation of absorption coefficient.
9. Setup reference ratio to be used in calculation of binary species parameter in lower atmosphere.
10. Setup reference ratio to be used in calculation of binary species parameter in upper atmosphere.
11. Rescale selffac and forfac for use in taumol.

Referenced by rrtmg_lw_run().