subroutine rrtmg_lw::rtrnmr ( real (kind=kind_phys), dimension(nbands), intent(in)  semiss, real (kind=kind_phys), dimension(nlay), intent(in)  delp, real (kind=kind_phys), dimension(0:nlp1), intent(in)  cldfrc, real (kind=kind_phys), dimension(nbands,nlay), intent(in)  taucld, real (kind=kind_phys), dimension(ngptlw,nlay), intent(in)  tautot, real (kind=kind_phys), dimension(nbands,0:nlay), intent(in)  pklay, real (kind=kind_phys), dimension(nbands,0:nlay), intent(in)  pklev, real (kind=kind_phys), dimension(ngptlw,nlay), intent(in)  fracs, real (kind=kind_phys), dimension(nbands), intent(in)  secdif, integer, intent(in)  nlay, integer, intent(in)  nlp1, real (kind=kind_phys), dimension(0:nlay), intent(out)  totuflux, real (kind=kind_phys), dimension(0:nlay), intent(out)  totdflux, real (kind=kind_phys), dimension(nlay), intent(out)  htr, real (kind=kind_phys), dimension(0:nlay), intent(out)  totuclfl, real (kind=kind_phys), dimension(0:nlay), intent(out)  totdclfl, real (kind=kind_phys), dimension(nlay), intent(out)  htrcl, real (kind=kind_phys), dimension(nlay,nbands), intent(out)  htrb  )

private

Parameters

semiss	lw surface emissivity
delp	layer pressure thickness (mb)
cldfrc	layer cloud fraction
taucld	layer cloud opt depth
tautot	total optical depth (gas+aerosols)
pklay	integrated planck func at lay temp
pklev	integrated planck func at lev temp
fracs	planck fractions
secdif	secant of diffusivity angle
nlay	number of vertical layers
nlp1	number of vertical levels (interfaces)
totuflux	total sky upward flux ( \(w/m^2\))
totdflux	total sky downward flux ( \(w/m^2\))
htr	total sky heating rate (k/sec or k/day)
totuclfl	clear sky upward flux ( \(w/m^2\))
totdclfl	clear sky downward flux ( \(w/m^2\))
htrcl	clear sky heating rate (k/sec or k/day)
htrb	spectral band lw heating rate (k/day)

rtrnmr General Algorithm

1. Setup maximum/random cloud overlap.
2. Initialize for radiative transfer
3. Downward radiative transfer loop:
   • cloudy layer
   • total sky radiance
   • clear sky radiance
4. Compute spectral emissivity & reflectance, include the contribution of spectrally varying longwave emissivity and reflection from the surface to the upward radiative transfer.
5. Compute total sky radiance.
6. Compute clear sky radiance.
7. Upward radiative transfer loop:
   • cloudy layer radiance
   • total sky radiance
   • clear sky radiance
8. Process longwave output from band for total and clear streams. calculate upward, downward, and net flux.

Referenced by rrtmg_lw_run().