Common Community Physics Package (CCPP) Scientific Documentation  Version 2.0
GFS radsw Main

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

Detailed Description

The SW radiation model in the current NOAA Environmental Modeling System (NEMS) was adapted from the RRTM radiation model developed by AER Inc. ([19]; [80]). It contains 14 spectral bands spanning a spectral wavenumber range of \(50000-820 cm^{-1}\) (corresponding to a wavelength range \(0.2-12.2\mu m\)), each spectral band focuses on a specific set of atmospheric absorbing species as shown in Table 1. To achieve great computation efficiency while at the same time to maintain a high degree of accuracy, the RRTM radiation model employs a corrected-k distribution method (i.e. mapping the highly spectral changing absorption coefficient, k, into a monotonic and smooth varying cumulative probability function, g). In the RRTM-SW, there are 16 unevenly distributed g points for each of the 14 bands for a total of 224 g points. The GCM version of the code (RRTMG-SW) uses a reduced number (various between 2 to 16) of g points for each of the bands that totals to 112 instead of the full set of 224. To get high quality for the scheme, many advanced techniques are used in RRTM such as carefully selecting the band structure to handle various major (key-species) and minor absorbers; deriving a binary parameter for a paired key molecular species in the same domain; and using two pressure regions (dividing level is at about 96mb) for optimal treatment of various species, etc.

Table 1. RRTMG-SW spectral bands and the corresponding absorbing species

Band #Wavenumber Range Lower Atm (Key)Lower Atm (Minor)Mid/Up Atm (Key)Mid/Up Atm (Minor)
16 2600-3250 H2O,CH4 CH4
17 3250-4000 H2O,CO2 H2O,CO2
18 4000-4650 H2O,CH4 CH4
19 4650-5150 H2O,CO2 CO2
20 5150-6150 H2O CH4 H2O CH4
21 6150-7700 H2O,CO2 H2O,CO2
22 7700-8050 H2O,O2 O2
23 8050-12850 H2O
24 12850-16000 H2O,O2 O3 O2 O3
25 16000-22650 H2O O3 O3
26 22650-29000
27 29000-38000 O3 O3
28 38000-50000 O3,O2 O3,O2
29 820-2600 H2O CO2 CO2 H2O

The RRTM-SW package includes three files:

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.

Argument Table

local_name standard_name long_name units rank type kind intent optional
plyr air_pressure_at_layer_for_radiation_in_hPa air pressure layer hPa 2 real kind_phys in F
plvl air_pressure_at_interface_for_radiation_in_hPa air pressure level hPa 2 real kind_phys in F
tlyr air_temperature_at_layer_for_radiation air temperature layer K 2 real kind_phys in F
tlvl air_temperature_at_interface_for_radiation air temperature level K 2 real kind_phys in F
qlyr water_vapor_specific_humidity_at_layer_for_radiation specific humidity layer kg kg-1 2 real kind_phys in F
olyr ozone_concentration_at_layer_for_radiation ozone concentration layer kg kg-1 2 real kind_phys in F
gasvmr_co2 volume_mixing_ratio_co2 volume mixing ratio co2 kg kg-1 2 real kind_phys in F
gasvmr_n2o volume_mixing_ratio_n2o volume mixing ratio no2 kg kg-1 2 real kind_phys in F
gasvmr_ch4 volume_mixing_ratio_ch4 volume mixing ratio ch4 kg kg-1 2 real kind_phys in F
gasvmr_o2 volume_mixing_ratio_o2 volume mixing ratio o2 kg kg-1 2 real kind_phys in F
gasvmr_co volume_mixing_ratio_co volume mixing ratio co kg kg-1 2 real kind_phys in F
gasvmr_cfc11 volume_mixing_ratio_cfc11 volume mixing ratio cfc11 kg kg-1 2 real kind_phys in F
gasvmr_cfc12 volume_mixing_ratio_cfc12 volume mixing ratio cfc12 kg kg-1 2 real kind_phys in F
gasvmr_cfc22 volume_mixing_ratio_cfc22 volume mixing ratio cfc22 kg kg-1 2 real kind_phys in F
gasvmr_ccl4 volume_mixing_ratio_ccl4 volume mixing ratio ccl4 kg kg-1 2 real kind_phys in F
icseed seed_random_numbers_sw seed for random number generation for shortwave radiation none 1 integer in F
aeraod aerosol_optical_depth_for_shortwave_bands_01-16 aerosol optical depth for shortwave bands 01-16 none 3 real kind_phys in F
aerssa aerosol_single_scattering_albedo_for_shortwave_bands_01-16 aerosol single scattering albedo for shortwave bands 01-16 frac 3 real kind_phys in F
aerasy aerosol_asymmetry_parameter_for_shortwave_bands_01-16 aerosol asymmetry paramter for shortwave bands 01-16 none 3 real kind_phys in F
sfcalb_nir_dir surface_albedo_due_to_near_IR_direct surface albedo due to near IR direct beam frac 1 real kind_phys in F
sfcalb_nir_dif surface_albedo_due_to_near_IR_diffused surface albedo due to near IR diffused beam frac 1 real kind_phys in F
sfcalb_uvis_dir surface_albedo_due_to_UV_and_VIS_direct surface albedo due to UV+VIS direct beam frac 1 real kind_phys in F
sfcalb_uvis_dif surface_albedo_due_to_UV_and_VIS_diffused surface albedo due to UV+VIS diffused beam frac 1 real kind_phys in F
cosz cosine_of_zenith_angle cosine of the solar zenit angle none 1 real kind_phys in F
solcon solar_constant solar constant W m-2 0 real kind_phys in F
nday daytime_points_dimension daytime points dimension count 0 integer in F
idxday daytime_points daytime points index 1 integer in F
npts horizontal_loop_extent horizontal dimension count 0 integer in F
nlay adjusted_vertical_layer_dimension_for_radiation number of vertical layers for radiation count 0 integer in F
nlp1 adjusted_vertical_level_dimension_for_radiation number of vertical levels for radiation count 0 integer in F
lprnt flag_print flag to print flag 0 logical in F
cld_cf total_cloud_fraction total cloud fraction frac 2 real kind_phys in F
lsswr flag_to_calc_sw flag to calculate SW irradiances flag 0 logical in F
hswc tendency_of_air_temperature_due_to_shortwave_heating_on_radiation_time_step shortwave total sky heating rate K s-1 2 real kind_phys inout F
topflx sw_fluxes_top_atmosphere shortwave total sky fluxes at the top of the atm W m-2 1 topfsw_type inout F
sfcflx sw_fluxes_sfc shortwave total sky fluxes at the Earth surface W m-2 1 sfcfsw_type inout F
hsw0 tendency_of_air_temperature_due_to_shortwave_heating_assuming_clear_sky_on_radiation_time_step shortwave clear sky heating rate K s-1 2 real kind_phys inout T
hswb sw_heating_rate_spectral shortwave total sky heating rate (spectral) K s-1 3 real kind_phys inout T
flxprf sw_fluxes sw fluxes total sky / csk and up / down at levels W m-2 2 profsw_type inout T
fdncmp components_of_surface_downward_shortwave_fluxes derived type for special components of surface downward shortwave fluxes W m-2 1 cmpfsw_type inout T
cld_lwp cloud_liquid_water_path cloud liquid water path g m-2 2 real kind_phys in T
cld_ref_liq mean_effective_radius_for_liquid_cloud mean effective radius for liquid cloud micron 2 real kind_phys in T
cld_iwp cloud_ice_water_path cloud ice water path g m-2 2 real kind_phys in T
cld_ref_ice mean_effective_radius_for_ice_cloud mean effective radius for ice cloud micron 2 real kind_phys in T
cld_rwp cloud_rain_water_path cloud rain water path g m-2 2 real kind_phys in T
cld_ref_rain mean_effective_radius_for_rain_drop mean effective radius for rain drop micron 2 real kind_phys in T
cld_swp cloud_snow_water_path cloud snow water path g m-2 2 real kind_phys in T
cld_ref_snow mean_effective_radius_for_snow_flake mean effective radius for snow flake micron 2 real kind_phys in T
cld_od_total cloud_optical_depth_weighted cloud optical depth, weighted none 2 real kind_phys out T
cld_od_layer cloud_optical_depth_layers_678 cloud optical depth, from bands 6,7,8 none 2 real kind_phys in T
cld_od cloud_optical_depth cloud optical depth none 2 real kind_phys in T
cld_ssa cloud_single_scattering_albedo cloud single scattering albedo frac 2 real kind_phys in T
cld_asy cloud_asymmetry_parameter cloud asymmetry parameter none 2 real kind_phys in T
errmsg ccpp_error_message error message for error handling in CCPP none 0 character len=* out F
errflg ccpp_error_flag error flag for error handling in CCPP flag 0 integer out F

RRTMG Shortwave Radiation Scheme General Algorithm

Modules

module  module_radsw_parameters
 This module is for specifying the band structures and program parameters used by the RRTMG-SW scheme.
 
module  module_radsw_ref
 This module contains the reference pressures (in logarithm form) at 59 vertical levels (TOA is omitted), and the mid-latitude summer (MLS) standard temperature profile for the 59 pressure layers that are used to establish pre calculated transmission tables.
 
module  module_radsw_cldprtb
 This module contains cloud radiative property coefficients.
 
module  module_radsw_sflux
 This module contains various indexes and coefficients for SW spectral bands, as well as the spectral distribution of solar flux. The values of spectral solar flux are derived based on a prescribed solar constant ( \(1368.22 W/m^2\)). Scaling will be applied for the actual inputted solar constant value.
 
module  module_radsw_kgb16
 This module sets up absorption coefficients for band 16: 2600-3250 cm-1 (low - h2o, ch4; high - ch4)
 
module  module_radsw_kgb17
 This module sets up absorption coeffients for band 17: 3250-4000 cm-1 (low - h2o,co2; high - h2o,co2)
 
module  module_radsw_kgb18
 This module sets up absorption coeffients for band 18: 4000-4650 cm-1 (low - h2o,ch4; high - ch4)
 
module  module_radsw_kgb19
 This module sets up absorption coeffients for band 19: 4650-5150 cm-1 (low - h2o,co2; high - co2)
 
module  module_radsw_kgb20
 This module sets up absorption coeffients for band 20: 5150-6150 cm-1 (low - h2o; high - h2o)
 
module  module_radsw_kgb21
 This module sets up absorption coeffients for band 21: 6150-7700 cm-1 (low - h2o,co2; high - h2o,co2)
 
module  module_radsw_kgb22
 This module sets up absorption coeffients for band 22: 7700-8050 cm-1 (low - h2o, o2; high - o2)
 
module  module_radsw_kgb23
 This module sets up absorption coeffients for band 23: 8050-12850 cm-1 (low - h2o; high - nothing)
 
module  module_radsw_kgb24
 This module sets up absorption coeffients for band 24: 12850-16000 cm-1 (low - h2o, o2; high - o2)
 
module  module_radsw_kgb25
 This module sets up absorption coeffients for band 25: 16000-22650 cm-1 (low - h2o; high - nothing)
 
module  module_radsw_kgb26
 This module sets up absorption coeffients for band 26: 22650-29000 cm-1 (low - nothing; high - nothing)
 
module  module_radsw_kgb27
 This module sets up absorption coeffients for band 27: 29000-38000 cm-1 (low - o3; high - o3)
 
module  module_radsw_kgb28
 This module sets up absorption coeffients for band 28: 38000-50000 cm-1 (low - o3,o2; high - o3,o2)
 
module  module_radsw_kgb29
 This module sets up absorption coeffients for band 29: 820-2600 cm-1 (low - h2o; high - co2)
 

Functions/Subroutines

subroutine, public rrtmg_sw::rrtmg_sw_run (plyr, plvl, tlyr, tlvl, qlyr, olyr, gasvmr_co2, gasvmr_n2o, gasvmr_ch4, gasvmr_o2, gasvmr_co, gasvmr_cfc11, gasvmr_cfc12, gasvmr_cfc22, gasvmr_ccl4, icseed, aeraod, aerssa, aerasy, sfcalb_nir_dir, sfcalb_nir_dif, sfcalb_uvis_dir, sfcalb_uvis_dif, cosz, solcon, NDAY, idxday, npts, nlay, nlp1, lprnt, cld_cf, lsswr, hswc, topflx, sfcflx, HSW0, HSWB, FLXPRF, FDNCMP, cld_lwp, cld_ref_liq, cld_iwp, cld_ref_ice, cld_rwp, cld_ref_rain, cld_swp, cld_ref_snow, cld_od_total, cld_od_layer, cld_od, cld_ssa, cld_asy, errmsg, errflg
 
subroutine taumol17
 The subroutine computes the optical depth in band 17: 3250-4000 cm-1 (low - h2o,co2; high - h2o,co2) More...
 
subroutine taumol18
 The subroutine computes the optical depth in band 18: 4000-4650 cm-1 (low - h2o,ch4; high - ch4) More...
 
subroutine taumol19
 The subroutine computes the optical depth in band 19: 4650-5150 cm-1 (low - h2o,co2; high - co2) More...
 
subroutine taumol20
 The subroutine computes the optical depth in band 20: 5150-6150 cm-1 (low - h2o; high - h2o) More...
 
subroutine taumol21
 The subroutine computes the optical depth in band 21: 6150-7700 cm-1 (low - h2o,co2; high - h2o,co2) More...
 
subroutine taumol22
 The subroutine computes the optical depth in band 22: 7700-8050 cm-1 (low - h2o,o2; high - o2) More...
 
subroutine taumol23
 The subroutine computes the optical depth in band 23: 8050-12850 cm-1 (low - h2o; high - nothing) More...
 
subroutine taumol24
 The subroutine computes the optical depth in band 24: 12850-16000 cm-1 (low - h2o,o2; high - o2) More...
 
subroutine taumol25
 The subroutine computes the optical depth in band 25: 16000-22650 cm-1 (low - h2o; high - nothing) More...
 
subroutine taumol26
 The subroutine computes the optical depth in band 26: 22650-29000 cm-1 (low - nothing; high - nothing) More...
 
subroutine taumol27
 The subroutine computes the optical depth in band 27: 29000-38000 cm-1 (low - o3; high - o3) More...
 
subroutine taumol28
 The subroutine computes the optical depth in band 28: 38000-50000 cm-1 (low - o3,o2; high - o3,o2) More...
 
subroutine taumol29
 The subroutine computes the optical depth in band 29: 820-2600 cm-1 (low - h2o; high - co2) More...
 
subroutine, public rrtmg_sw::rswinit (me)
 This subroutine initializes non-varying module variables, conversion factors, and look-up tables. More...
 
subroutine rrtmg_sw::cldprop (cfrac, cliqp, reliq, cicep, reice, cdat1, cdat2, cdat3, cdat4, cf1, nlay, ipseed, taucw, ssacw, asycw, cldfrc, cldfmc )
 This subroutine computes the cloud optical properties for each cloudy layer and g-point interval. More...
 
subroutine rrtmg_sw::mcica_subcol (cldf, nlay, ipseed, lcloudy )
 This subroutine computes the sub-colum cloud profile flag array. More...
 
subroutine rrtmg_sw::setcoef (pavel, tavel, h2ovmr, nlay, nlp1, laytrop, jp, jt, jt1, fac00, fac01, fac10, fac11, selffac, selffrac, indself, forfac, forfrac, indfor )
 This subroutine computes various coefficients needed in radiative transfer calculation. More...
 
subroutine rrtmg_sw::spcvrtc (ssolar, cosz, sntz, albbm, albdf, sfluxzen, cldfrc, cf1, cf0, taug, taur, tauae, ssaae, asyae, taucw, ssacw, asycw, nlay, nlp1, fxupc, fxdnc, fxup0, fxdn0, ftoauc, ftoau0, ftoadc, fsfcuc, fsfcu0, fsfcdc, fsfcd0, sfbmc, sfdfc, sfbm0, sfdf0, suvbfc, suvbf0 )
 This subroutine computes the shortwave radiative fluxes using two-stream method. More...
 
subroutine rrtmg_sw::spcvrtm (ssolar, cosz, sntz, albbm, albdf, sfluxzen, cldfmc, cf1, cf0, taug, taur, tauae, ssaae, asyae, taucw, ssacw, asycw, nlay, nlp1, fxupc, fxdnc, fxup0, fxdn0, ftoauc, ftoau0, ftoadc, fsfcuc, fsfcu0, fsfcdc, fsfcd0, sfbmc, sfdfc, sfbm0, sfdf0, suvbfc, suvbf0 )
 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...
 
subroutine rrtmg_sw::vrtqdr (zrefb, zrefd, ztrab, ztrad, zldbt, ztdbt, NLAY, NLP1, zfu, zfd )
 This subroutine is called by spcvrtc() and spcvrtm(), and computes the upward and downward radiation fluxes. More...
 
subroutine rrtmg_sw::taumol (colamt, colmol, fac00, fac01, fac10, fac11, jp, jt, jt1, laytrop, forfac, forfrac, indfor, selffac, selffrac, indself, nlay, sfluxzen, taug, taur )
 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) More...