module_radsw_main

This module includes NCEP's modifications of the rrtmg-sw radiation code from AER. More...

Detailed Description

This module includes NCEP's modifications of the rrtmg-sw radiation code from AER.

The RRTM-SW package includes three files:

• radsw_param.f, which contains:
  • module_radsw_parameters: band parameters set up
• radsw_datatb.f, which contains:
  • module_radsw_ref: reference temperature and pressure
  • module_radsw_cldprtb: cloud property coefficients table
  • module_radsw_sflux: spectral distribution of solar flux
  • module_radsw_kgbnn: absorption coefficents for 14 bands, where nn = 16-29
• radsw_main.f, which contains:
  • module_radsw_main: the main SW radiation trnsfer, which contains two externally callable subroutines:
    • swrad(): the main radiation routine
    • rswinit(): the initialization routine

All the SW radiation subprograms become contained subprograms in module 'module_radsw_main' and many of them are not directly accessable from places outside the module.

Author

Eli J. Mlawer, emlaw.nosp@m.er@a.nosp@m.er.co.nosp@m.m

Jennifer S. Delamere, jdela.nosp@m.mer@.nosp@m.aer.c.nosp@m.om

Michael J. Iacono, miaco.nosp@m.no@a.nosp@m.er.co.nosp@m.m

Shepard A. Clough

Version

NCEP SW v5.1 Nov 2012 -RRTMG-SW v3.8

The authors wish to acknowledge the contributions of the following people: Steven J. Taubman, Karen Cady-Pereira, Patrick D. Brown, Ronald E. Farren, Luke Chen, Robert Bergstrom.

Copyright

2002-2007, Atmospheric & Environmental Research, Inc. (AER). This software may be used, copied, or redistributed as long as it is not sold and this copyright notice is reproduced on each copy made. This model is provided as is without any express or implied warranties. (http://www.rtweb.aer.com/)

Collaboration diagram for module_radsw_main:

Modules
	module_radsw_kgbnn

Modules
module	module_radsw_parameters
	This module contains SW band parameters set up.

Functions/Subroutines
subroutine, public	module_radsw_main::rswinit
	This subroutine initializes non-varying module variables, conversion factors, and look-up tables. More...
subroutine	module_radsw_main::mcica_subcol
	This subroutine computes the sub-colum cloud profile flag array. More...
subroutine	module_radsw_main::setcoef
	This subroutine computes various coefficients needed in radiative transfer calculation. More...
subroutine	module_radsw_main::spcvrtm
	This subroutine computes the shortwave radiative fluxes using two-stream method of h. barder and mcica,the monte-carlo independent column approximation, for the representation of sub-grid cloud variability (i.e. cloud overlap). More...

constant values
real(kind=kind_phys), parameter	module_radsw_main::eps = 1.0e-6
real(kind=kind_phys), parameter	module_radsw_main::oneminus = 1.0 - eps
real(kind=kind_phys), parameter	module_radsw_main::bpade = 1.0/0.278
	pade approx constant
real(kind=kind_phys), parameter	module_radsw_main::stpfac = 296.0/1013.0
real(kind=kind_phys), parameter	module_radsw_main::ftiny = 1.0e-12
real(kind=kind_phys), parameter	module_radsw_main::s0 = 1368.22
	internal solar constant
real(kind=kind_phys), parameter	module_radsw_main::f_zero = 0.0
real(kind=kind_phys), parameter	module_radsw_main::f_one = 1.0

atomic weights for conversion from mass to volume mixing ratios
real(kind=kind_phys), parameter	module_radsw_main::amdw = con_amd/con_amw
real(kind=kind_phys), parameter	module_radsw_main::amdo3 = con_amd/con_amo3

band indices
integer, dimension(nblow:nbhgh)	module_radsw_main::nspa
integer, dimension(nblow:nbhgh)	module_radsw_main::nspb
integer, dimension(nblow:nbhgh)	module_radsw_main::idxsfc
	band index for sfc flux
integer, dimension(nblow:nbhgh)	module_radsw_main::idxebc
	band index for cld prop
integer, parameter	module_radsw_main::nuvb = 27
	uv-b band index

logical flags for optional output fields
logical	module_radsw_main::lhswb = .false.
logical	module_radsw_main::lhsw0 = .false.
logical	module_radsw_main::lflxprf = .false.
logical	module_radsw_main::lfdncmp = .false.
real(kind=kind_phys), dimension(0:ntbmx)	module_radsw_main::exp_tbl
	those data will be set up only once by "rswinit"
real(kind=kind_phys)	module_radsw_main::heatfac
	the factor for heating rates (in k/day, or k/sec set by subroutine 'rswinit')
integer, parameter	module_radsw_main::ipsdsw0 = 1
	initial permutation seed used for sub-column cloud scheme
subroutine, public	module_radsw_main::swrad
	This subroutine is the main SW radiation routine. More...
subroutine	module_radsw_main::cldprop
	This subroutine computes the cloud optical properties for each cloudy layer and g-point interval. More...
subroutine	module_radsw_main::spcvrtc
	This subroutine computes the shortwave radiative fluxes using two-stream method. More...
subroutine	module_radsw_main::vrtqdr
	This subroutine is called by spcvrtc() and spcvrtm(), and computes the upward and downward radiation fluxes. More...
subroutine	module_radsw_main::taumol
	This subroutine calculates optical depths for gaseous absorption and rayleigh scattering subroutine called taumol## (## = 16-29) More...
subroutine	taumol16
	The subroutine computes the optical depth in band 16: 2600-3250 cm-1 (low - h2o,ch4; high - ch4)

Function/Subroutine Documentation

subroutine module_radsw_main::cldprop ( )

private

This subroutine computes the cloud optical properties for each cloudy layer and g-point interval.

Parameters

cfrac	layer cloud fraction for physparam::iswcliq > 0 (prognostic cloud scheme) - - -
cliqp	layer in-cloud liq water path ( \(g/m^2\))
reliq	mean eff radius for liq cloud (micron)
cicep	layer in-cloud ice water path ( \(g/m^2\))
reice	mean eff radius for ice cloud (micron)
cdat1	layer rain drop water path ( \(g/m^2\))
cdat2	effective radius for rain drop (micron)
cdat3	layer snow flake water path( \(g/m^2\))
cdat4	mean eff radius for snow flake(micron) for physparam::iswcliq = 0 (diagnostic cloud scheme) - - -
cliqp	not used
cicep	not used
reliq	not used
reice	not used
cdat1	layer cloud optical depth
cdat2	layer cloud single scattering albedo
cdat3	layer cloud asymmetry factor
cdat4	optional use
cf1	effective total cloud cover at surface
nlay	vertical layer number
ipseed	permutation seed for generating random numbers (isubcsw>0)
taucw	cloud optical depth, w/o delta scaled
ssacw	weighted cloud single scattering albedo (ssa = ssacw / taucw)
asycw	weighted cloud asymmetry factor (asy = asycw / ssacw)
cldfrc	cloud fraction of grid mean value
cldfmc	cloud fraction for each sub-column

General Algorithm

1. Compute cloud radiative properties for a cloudy column.
   • Compute optical properties for rain and snow.
     For rain: tauran/ssaran/asyran
     For snow: tausnw/ssasnw/asysnw
   • Calculation of absorption coefficients due to water clouds
     For water clouds: tauliq/ssaliq/asyliq
   • Calculation of absorption coefficients due to ice clouds
     For ice clouds: tauice/ssaice/asyice
   • For Prognostic cloud scheme: sum up the cloud optical property:
     \( taucw=tauliq+tauice+tauran+tausnw \)
     \( ssacw=ssaliq+ssaice+ssaran+ssasnw \)
     \( asycw=asyliq+asyice+asyran+asysnw \)
2. if physparam::isubcsw > 0, call mcica_subcol() to distribute cloud properties to each g-point.

Definition at line 1458 of file radsw_main.f.

References idxebc, physparam::isubcsw, physparam::iswcice, physparam::iswcliq, mcica_subcol(), module_radsw_parameters::nbhgh, module_radsw_parameters::nblow, and module_radsw_parameters::ngptsw.

Referenced by swrad().

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subroutine module_radsw_main::mcica_subcol ( )

private

This subroutine computes the sub-colum cloud profile flag array.

Parameters

cldf	layer cloud fraction
nlay	number of model vertical layers
ipseed	permute seed for random num generator
lcloudy	sub-colum cloud profile flag array

Definition at line 1819 of file radsw_main.f.

References physparam::iovrsw, and module_radsw_parameters::ngptsw.

Referenced by cldprop().

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subroutine, public module_radsw_main::rswinit

(

)

This subroutine initializes non-varying module variables, conversion factors, and look-up tables.

Parameters

me	print control for parallel process

Definition at line 1272 of file radsw_main.f.

References bpade, physcons::con_cp, physcons::con_g, exp_tbl, heatfac, physparam::icldflg, physparam::iovrsw, physparam::isubcsw, physparam::iswcliq, physparam::iswmode, physparam::iswrate, physparam::iswrgas, and module_radsw_parameters::ntbmx.

Referenced by module_radiation_driver::radinit().

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subroutine module_radsw_main::setcoef ( )

private

This subroutine computes various coefficients needed in radiative transfer calculation.

Parameters

pavel	layer pressure (mb)
tavel	layer temperature (k)
h2ovmr	layer w.v. volumn mixing ratio (kg/kg)
nlay	total number of vertical layers
nlp1	total number of vertical levels
laytrop	tropopause layer index (unitless)
jp	indices of lower reference pressure
jt,jt1	indices of lower reference temperatures at levels of jp and jp+1
facij	factors mltiply the reference ks,i,j=0/1 for lower/higher of the 2 appropriate temperature and altitudes.
selffac	scale factor for w. v. self-continuum equals (w.v. density)/(atmospheric density at 296k and 1013 mb)
seffrac	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

Definition at line 2001 of file radsw_main.f.

References module_radsw_ref::preflog.

Referenced by swrad().

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subroutine module_radsw_main::spcvrtc ( )

private

This subroutine computes the shortwave radiative fluxes using two-stream method.

Parameters

ssolar	incoming solar flux at top
cosz	cosine solar zenith angle
sntz	secant solar zenith angle
albbm	surface albedo for direct beam radiation
albdf	surface albedo for diffused radiation
sfluxzen	spectral distribution of incoming solar flux
cldfrc	layer cloud fraction
cf1	>0: cloudy sky, otherwise: clear sky
cf0	=1-cf1
taug	spectral optical depth for gases
taur	optical depth for rayleigh scattering
tauae	aerosols optical depth
ssaae	aerosols single scattering albedo
asyae	aerosols asymmetry factor
taucw	weighted cloud optical depth
ssacw	weighted cloud single scat albedo
asycw	weighted cloud asymmetry factor
nlay,nlp1	number of layers/levels
fxupc	tot sky upward flux
fxdnc	tot sky downward flux
fxup0	clr sky upward flux
fxdn0	clr sky downward flux
ftoauc	tot sky toa upwd flux
ftoau0	clr sky toa upwd flux
ftoadc	toa downward (incoming) solar flux
fsfcuc	tot sky sfc upwd flux
fsfcu0	clr sky sfc upwd flux
fsfcdc	tot sky sfc dnwd flux
fsfcd0	clr sky sfc dnwd flux
sfbmc	tot sky sfc dnwd beam flux (nir/uv+vis)
sfdfc	tot sky sfc dnwd diff flux (nir/uv+vis)
sfbm0	clr sky sfc dnwd beam flux (nir/uv+vis)
sfdf0	clr sky sfc dnwd diff flux (nir/uv+vis)
suvbfc	tot sky sfc dnwd uv-b flux
suvbf0	clr sky sfc dnwd uv-b flux

General Algorithm

1. Initialize output fluxes.
2. Compute clear-sky optical parameters, layer reflectance and transmittance.
   • Set up toa direct beam and surface values (beam and diff)
   • Delta scaling for clear-sky condition
   • General two-stream expressions for physparam::iswmode
   • Compute homogeneous reflectance and transmittance for both conservative and non-conservative scattering
   • Pre-delta-scaling clear and cloudy direct beam transmittance
   • Call swflux() to compute the upward and downward radiation fluxes
3. Compute total sky optical parameters, layer reflectance and transmittance.
   • Set up toa direct beam and surface values (beam and diff)
   • Delta scaling for total-sky condition
   • General two-stream expressions for physparam::iswmode
   • Compute homogeneous reflectance and transmittance for conservative scattering and non-conservative scattering
   • Pre-delta-scaling clear and cloudy direct beam transmittance
   • Call swflux() to compute the upward and downward radiation fluxes
4. Process and save outputs.

Definition at line 2191 of file radsw_main.f.

References bpade, exp_tbl, idxsfc, physparam::iswmode, module_radsw_parameters::nblow, module_radsw_parameters::ngb, module_radsw_parameters::ngptsw, module_radsw_parameters::ntbmx, nuvb, and vrtqdr().

Referenced by swrad().

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subroutine module_radsw_main::spcvrtm ( )

private

This subroutine computes the shortwave radiative fluxes using two-stream method of h. barder and mcica,the monte-carlo independent column approximation, for the representation of sub-grid cloud variability (i.e. cloud overlap).

Parameters

ssolar	incoming solar flux at top
cosz	cosine solar zenith angle
sntz	secant solar zenith angle
albbm	surface albedo for direct beam radiation
albdf	surface albedo for diffused radiation
sfluxzen	spectral distribution of incoming solar flux
cldfmc	layer cloud fraction for g-point
cf1	>0: cloudy sky, otherwise: clear sky
cf0	=1-cf1
taug	spectral optical depth for gases
taur	optical depth for rayleigh scattering
tauae	aerosols optical depth
ssaae	aerosols single scattering albedo
asyae	aerosols asymmetry factor
taucw	weighted cloud optical depth
ssacw	weighted cloud single scat albedo
asycw	weighted cloud asymmetry factor
nlay,nlp1	number of layers/levels
fxupc	tot sky upward flux
fxdnc	tot sky downward flux
fxup0	clr sky upward flux
fxdn0	clr sky downward flux
ftoauc	tot sky toa upwd flux
ftoau0	clr sky toa upwd flux
ftoadc	toa downward (incoming) solar flux
fsfcuc	tot sky sfc upwd flux
fsfcu0	clr sky sfc upwd flux
fsfcdc	tot sky sfc dnwd flux
fsfcd0	clr sky sfc dnwd flux
sfbmc	tot sky sfc dnwd beam flux (nir/uv+vis)
sfdfc	tot sky sfc dnwd diff flux (nir/uv+vis)
sfbm0	clr sky sfc dnwd beam flux (nir/uv+vis)
sfdf0	clr sky sfc dnwd diff flux (nir/uv+vis)
suvbfc	tot sky sfc dnwd uv-b flux
suvbf0	clr sky sfc dnwd uv-b flux

1. Initialize output fluxes.
2. Compute clear-sky optical parameters, layer reflectance and transmittance.
   • Set up toa direct beam and surface values (beam and diff)
   • Delta scaling for clear-sky condition
   • General two-stream expressions for physparam::iswmode
   • Compute homogeneous reflectance and transmittance for both conservative and non-conservative scattering
   • Pre-delta-scaling clear and cloudy direct beam transmittance
   • Call swflux() to compute the upward and downward radiation fluxes
3. Compute total sky optical parameters, layer reflectance and transmittance.
   • Set up toa direct beam and surface values (beam and diff)
   • Delta scaling for total-sky condition
   • General two-stream expressions for physparam::iswmode
   • Compute homogeneous reflectance and transmittance for conservative scattering and non-conservative scattering
   • Pre-delta-scaling clear and cloudy direct beam transmittance
   • Call swflux() to compute the upward and downward radiation fluxes
4. Process and save outputs.

Definition at line 2951 of file radsw_main.f.

References bpade, exp_tbl, idxsfc, physparam::iswmode, module_radsw_parameters::nblow, module_radsw_parameters::ngb, module_radsw_parameters::ngptsw, module_radsw_parameters::ntbmx, nuvb, and vrtqdr().

Referenced by swrad().

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subroutine, public module_radsw_main::swrad

(

)

This subroutine is the main SW radiation routine.

Parameters

plyr	model layer mean pressure in mb
plvl	model level pressure in mb
tlyr	model layer mean temperature in K
tlvl	model level temperature in K (not in use)
qlyr	layer specific humidity in gm/gm
olyr	layer ozone concentration in gm/gm
gasvmr	atmospheric constent gases (:,:,1) - co2 volume mixing ratio (:,:,2) - n2o volume mixing ratio (:,:,3) - ch4 volume mixing ratio (:,:,4) - o2 volume mixing ratio (:,:,5) - co volume mixing ratio (not used) (:,:,6) - cfc11 volume mixing ratio (not used) (:,:,7) - cfc12 volume mixing ratio (not used) (:,:,8) - cfc22 volume mixing ratio (not used) (:,:,9) - ccl4 volume mixing ratio (not used)
clouds	cloud profile (:,:,1) - layer total cloud fraction (:,:,2) - layer in-cloud liq water path ( \(g/m^2\)) (:,:,3) - mean eff radius for liq cloud (micron) (:,:,4) - layer in-cloud ice water path ( \(g/m^2\)) (:,:,5) - mean eff radius for ice cloud (micron) (:,:,6) - layer rain drop water path ( \(g/m^2\)) (:,:,7) - mean eff radius for rain drop (micron) (:,:,8) - layer snow flake water path ( \(g/m^2\)) (:,:,9) - mean eff radius for snow flake (micron)
icseed	auxiliary special cloud related array.
aerosols	aerosol optical properties (:,:,:,1) - optical depth (:,:,:,2) - single scattering albedo (:,:,:,3) - asymmetry parameter
sfcalb	surface albedo in fraction (:,1) - near ir direct beam albedo (:,2) - near ir diffused albedo (:,3) - uv+vis direct beam albedo (:,4) - uv+vis diffused albedo
cosz	cosine of solar zenith angle
solcon	solar constant ( \(W/m^2\))
NDAY	num of daytime points
idxday	index array for daytime points
npts	number of horizontal points
nlay,nlp1	vertical layer/lavel numbers
lprnt	logical check print flag
hswc	total sky heating rates (k/sec or k/day)
topflx	radiation fluxes at toa ( \(W/m^2\)), components: upfxc - total sky upward flux at toa dnflx - total sky downward flux at toa upfx0 - clear sky upward flux at toa
sfcflx	radiation fluxes at sfc ( \(W/m^2\)), components: upfxc - total sky upward flux at sfc dnfxc - total sky downward flux at sfc upfx0 - clear sky upward flux at sfc dnfx0 - clear sky downward flux at sfc
hswb	spectral band total sky heating rates
hsw0	clear sky heating rates (k/sec or k/day)
flxprf	level radiation fluxes ( \( W/m^2 \)), components: dnfxc - total sky downward flux at interface upfxc - total sky upward flux at interface dnfx0 - clear sky downward flux at interface upfx0 - clear sky upward flux at interface
fdncmp	surface downward fluxes ( \(W/m^2\)), components: uvbfc - total sky downward uv-b flux at sfc uvbf0 - clear sky downward uv-b flux at sfc nirbm - downward surface nir direct beam flux nirdf - downward surface nir diffused flux visbm - downward surface uv+vis direct beam flux visdf - downward surface uv+vis diffused flux

General Algorithm

1. Compute solar constant adjustment factor (s0fac) according to solcon.
2. Initial output arrays (and optional) as zero.
3. Change random number seed value for each radiation invocation (isubcsw =1 or 2).
4. Prepare surface albedo: bm,df - dir,dif; 1,2 - nir,uvv.
5. Prepare atmospheric profile for use in rrtm.
6. Set absorber and gas column amount, convert from volume mixing ratio to molec/cm2 based on coldry (scaled to 1.0e-20)
   • colamt(nlay,maxgas):column amounts of absorbing gases 1 to maxgas are for h2o,co2,o3,n2o,ch4,o2,co, respectively ( \( mol/cm^2 \))
7. Read aerosol optical properties from 'aerosols'.
8. Read cloud optical properties from 'clouds'.
9. Compute fractions of clear sky view:
   • random overlapping
   • max/ran overlapping
   • maximum overlapping
10. For cloudy sky column, call cldprop() to compute the cloud optical properties for each cloudy layer.
11. Call setcoef() to compute various coefficients needed in radiative transfer calculations.
12. Call taumol() to calculate optical depths for gaseous absorption and rayleigh scattering
13. Call the 2-stream radiation transfer model:
    • if physparam::isubcsw .le.0, using standard cloud scheme, call spcvrtc().
    • if physparam::isubcsw .gt.0, using mcica cloud scheme, call spcvrtm().
14. Save outputs.

Definition at line 483 of file radsw_main.f.

References cldprop(), physcons::con_amd, physcons::con_amw, physcons::con_avgd, physcons::con_g, heatfac, physparam::iovrsw, ipsdsw0, physparam::isubcsw, physparam::iswcliq, physparam::iswrgas, physparam::ivflip, s0, setcoef(), spcvrtc(), spcvrtm(), and taumol().

Referenced by module_radiation_driver::grrad().

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subroutine module_radsw_main::taumol ( )

private

This subroutine calculates optical depths for gaseous absorption and rayleigh scattering
subroutine called taumol## (## = 16-29)

Parameters

colamt	column amounts of absorbing gases the index are for h2o, co2, o3, n2o, ch4, and o2, respectively \((mol/cm^2)\)
colmol	total column amount (dry air+water vapor)
facij	for each layer, these are factors that are needed to compute the interpolation factors that multiply the appropriate reference k-values. a value of 0/1 for i,j indicates that the corresponding factor multiplies reference k-value for the lower/higher of the two appropriate temperatures, and altitudes, respectively.
jp	the index of the lower (in altitude) of the two appropriate ref pressure levels needed for interpolation.
jt,jt1	the indices of the lower of the two approp ref temperatures needed for interpolation (for pressure levels jp and jp+1, respectively)
laytrop	tropopause layer index
forfac	scale factor needed to foreign-continuum.
forfrac	factor needed for temperature interpolation
indfor	index of the lower of the two appropriate reference temperatures needed for foreign-continuum interpolation
selffac	scale factor needed to h2o self-continuum.
selffrac	factor needed for temperature interpolation of reference h2o self-continuum data
indself	index of the lower of the two appropriate reference temperatures needed for the self-continuum interpolation
nlay	number of vertical layers
sfluxzen	spectral distribution of incoming solar flux
taug	spectral optical depth for gases
taur	opt depth for rayleigh scattering

General Algorithm

• Call taumol## (##: 16-29) to calculate layer optical depth.
  • call taumol16()
  • call taumol17()
  • call taumol18()
  • call taumol19()
  • call taumol20()
  • call taumol21()
  • call taumol22()
  • call taumol23()
  • call taumol24()
  • call taumol25()
  • call taumol26()
  • call taumol27()
  • call taumol28()
  • call taumol29()

Definition at line 3792 of file radsw_main.f.

References module_radsw_parameters::nbhgh, module_radsw_parameters::nblow, taumol16(), taumol17(), taumol18(), taumol19(), taumol20(), taumol21(), taumol22(), taumol23(), taumol24(), taumol25(), taumol26(), taumol27(), taumol28(), and taumol29().

Referenced by swrad().

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subroutine module_radsw_main::vrtqdr ( )

private

This subroutine is called by spcvrtc() and spcvrtm(), and computes the upward and downward radiation fluxes.

Parameters

zrefb	layer direct beam reflectivity
zrefd	layer diffuse reflectivity
ztrab	layer direct beam transmissivity
ztrad	layer diffuse transmissivity
zldbt	layer mean beam transmittance
ztdbt	total beam transmittance at levels
NLAY,NLP1	number of layers/levels
zfu	upward flux at layer interface
zfd	downward flux at layer interface

General Algorithm

1. Link lowest layer with surface.
2. Pass from bottom to top.
3. Upper boundary conditions
4. Pass from top to bottom
5. Up and down-welling fluxes at levels.

Definition at line 3656 of file radsw_main.f.

Referenced by spcvrtc(), and spcvrtm().

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