GFS RRTMG-LW Main Module

This module includes NCEP's modifications of the RRTMG-LW radiation code from AER.The RRTMG-LW package includes three files: More...

Modules
module	module_radlw_avplank
	This module contains plank flux data.
module	module_radlw_ref
	This module contains reference temperature and pressure.
module	module_radlw_cldprlw
	This module contains cloud property coefficients.
module	module_radlw_kgb01
	This module sets up absorption coefficients for band 01: 10-350 cm-1 (low - h2o; high - h2o)
module	module_radlw_kgb02
	This module sets up absorption coefficients for band 02: 350-500 cm-1 (low - h2o; high - h2o)
module	module_radlw_kgb03
	This module sets up absorption coefficients for band 03: 500-630 cm-1 (low - h2o, co2; high - h2o, co2)
module	module_radlw_kgb04
	This module sets up absorption coefficients for band 04: 630-700 cm-1 (low - h2o, co2; high - co2, o3)
module	module_radlw_kgb05
	This module sets up absorption coefficients for band 05: 700-820 cm-1 (low - h2o, co2; high - co2, o3)
module	module_radlw_kgb06
	This module sets up absorption coefficients for band 06: 820-980 cm-1 (low - h2o; high - /)
module	module_radlw_kgb07
	This module sets up absorption coefficients for band 07: 980-1080 cm-1 (low - h2o, o3; high - o3)
module	module_radlw_kgb08
	This module sets up absorption coefficients for band 08: 1080-1180 cm-1 (low - h2o; high - o3)
module	module_radlw_kgb09
	This module sets up absorption coefficients for band 09: 1180-1390 cm-1 (low - h2o, ch4; high - ch4)
module	module_radlw_kgb10
	This module sets up absorption coefficients for band 10: 1390-1480 cm-1 (low - h2o; high - h2o)
module	module_radlw_kgb11
	This module sets up absorption coefficients for band 11: 1480-1800 cm-1 (low - h2o; high - h2o)
module	module_radlw_kgb12
	This module sets up absorption coefficients for band 12: 1800-2080 cm-1 (low - h2o, co2; high - /)
module	module_radlw_kgb13
	This module sets up absorption coefficients for band 13: 2080-2250 cm-1 (low - h2o, n2o; high - /)
module	module_radlw_kgb14
	This module sets up absorption coefficients for band 14: 2250-2380 cm-1 (low - co2; high - co2)
module	module_radlw_kgb15
	This module sets up absorption coefficients for band 15: 2380-2600 cm-1 (low - n2o, co2; high - /)
module	module_radlw_kgb16
	This module sets up absorption coefficients for band 16: 2600-3000 cm-1 (low - h2o, ch4; high - /)
module	module_radlw_parameters
	This module contains LW band parameters set up.

Functions/Subroutines
subroutine, public	rrtmg_lw::rrtmg_lw_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, sfemis, sfgtmp, dzlyr, delpin, de_lgth, alpha, npts, nlay, nlp1, lprnt, cld_cf, lslwr, top_at_1, iovr, iovr_rand, iovr_maxrand, iovr_max, iovr_dcorr, iovr_exp, iovr_exprand, inc_minor_gas, ilwcliq, ilwcice, isubclw, hlwc, topflx, sfcflx, cldtau, hlw0, hlwb, flxprf, cld_lwp, cld_ref_liq, cld_iwp, cld_ref_ice, cld_rwp, cld_ref_rain, cld_swp, cld_ref_snow, cld_od, errmsg, errflg)
subroutine, public	rrtmg_lw::rlwinit (me, rad_hr_units, inc_minor_gas, ilwcliq, isubclw, iovr, iovr_rand, iovr_maxrand, iovr_max, iovr_dcorr, iovr_exp, iovr_exprand, errflg, errmsg)
	This subroutine performs calculations necessary for the initialization of the longwave model, which includes non-varying model variables, conversion factors, and look-up tables

Detailed Description

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

The RRTMG-LW package includes three files:

• radlw_param.f, which contains:
  • module_radlw_parameters: band parameters set up
• radlw_datatb.f, which contains modules:
  • module_radlw_avplank: plank flux data
  • module_radlw_ref: reference temperature and pressure
  • module_radlw_cldprlw: cloud property coefficients
  • module_radlw_kgbnn: absorption coeffients for 16 bands, where nn = 01-16
• radlw_main.f, which contains:
  • rrtmg_lw_run(): the main LW radiation routine
  • rlwinit(): the initialization routine

Version

NCEP LW v5.1 Nov 2012 -RRTMG-LW v4.82

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/)

Argument Table

RRTMG Longwave Radiation Scheme General Algorithm

Function/Subroutine Documentation

rlwinit()

subroutine, public rrtmg_lw::rlwinit	(	integer, intent(in)	me,
		integer, intent(in)	rad_hr_units,
		logical, intent(in)	inc_minor_gas,
		integer, intent(in)	ilwcliq,
		integer, intent(in)	isubclw,
		integer, intent(in)	iovr,
		integer, intent(in)	iovr_rand,
		integer, intent(in)	iovr_maxrand,
		integer, intent(in)	iovr_max,
		integer, intent(in)	iovr_dcorr,
		integer, intent(in)	iovr_exp,
		integer, intent(in)	iovr_exprand,
		integer, intent(out)	errflg,
		character(len=*), intent(out)	errmsg
	)

This subroutine performs calculations necessary for the initialization of the longwave model, which includes non-varying model variables, conversion factors, and look-up tables

Lookup tables are computed for use in the lw radiative transfer, and input absorption coefficient data for each spectral band are reduced from 256 g-point intervals to 140.

Parameters

me	print control for parallel process

rlwinit General Algorithm

• Setup default surface emissivity for each band.

• Setup constant factors for flux and heating rate the 1.0e-2 is to convert pressure from mb to \(N/m^2\).

• Compute lookup tables for transmittance, tau transition function, and clear sky tau (for the cloudy sky radiative transfer). tau is computed as a function of the tau transition function, transmittance is calculated as a function of tau, and the tau transition function is calculated using the linear in tau formulation at values of tau above 0.01. tf is approximated as tau/6 for tau < 0.01. all tables are computed at intervals of 0.001. the inverse of the constant used in the pade approximation to the tau transition function is set to b.

Definition at line 1323 of file radlw_main.F90.

rrtmg_lw_run()

subroutine, public rrtmg_lw::rrtmg_lw_run	(	real (kind=kind_phys), dimension(:,:), intent(in)	plyr,
		real (kind=kind_phys), dimension(:,:), intent(in)	plvl,
		real (kind=kind_phys), dimension(:,:), intent(in)	tlyr,
		real (kind=kind_phys), dimension(:,:), intent(in)	tlvl,
		real (kind=kind_phys), dimension(:,:), intent(in)	qlyr,
		real (kind=kind_phys), dimension(:,:), intent(in)	olyr,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_co2,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_n2o,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_ch4,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_o2,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_co,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_cfc11,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_cfc12,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_cfc22,
		real (kind=kind_phys), dimension(:,:), intent(in)	gasvmr_ccl4,
		integer, dimension(npts), intent(in)	icseed,
		real (kind=kind_phys), dimension(:,:,:), intent(in)	aeraod,
		real (kind=kind_phys), dimension(:,:,:), intent(in)	aerssa,
		real (kind=kind_phys), dimension(:), intent(in)	sfemis,
		real (kind=kind_phys), dimension(:), intent(in)	sfgtmp,
		real (kind=kind_phys), dimension(:,:), intent(in)	dzlyr,
		real (kind=kind_phys), dimension(:,:), intent(in)	delpin,
		real (kind=kind_phys), dimension(:), intent(in)	de_lgth,
		real (kind=kind_phys), dimension(npts,nlay), intent(in)	alpha,
		integer, intent(in)	npts,
		integer, intent(in)	nlay,
		integer, intent(in)	nlp1,
		logical, intent(in)	lprnt,
		real (kind=kind_phys), dimension(:,:), intent(in)	cld_cf,
		logical, intent(in)	lslwr,
		logical, intent(in)	top_at_1,
		integer, intent(in)	iovr,
		integer, intent(in)	iovr_rand,
		integer, intent(in)	iovr_maxrand,
		integer, intent(in)	iovr_max,
		integer, intent(in)	iovr_dcorr,
		integer, intent(in)	iovr_exp,
		integer, intent(in)	iovr_exprand,
		logical, intent(in)	inc_minor_gas,
		integer, intent(in)	ilwcliq,
		integer, intent(in)	ilwcice,
		integer, intent(in)	isubclw,
		real (kind=kind_phys), dimension(:,:), intent(inout)	hlwc,
		type (topflw_type), dimension(:), intent(inout)	topflx,
		type (sfcflw_type), dimension(:), intent(inout)	sfcflx,
		real (kind=kind_phys), dimension(:,:), intent(inout)	cldtau,
		real (kind=kind_phys), dimension(:,:), intent(inout), optional	hlw0,
		real (kind=kind_phys), dimension(:,:,:), intent(inout), optional	hlwb,
		type (proflw_type), dimension(:,:), intent(inout), optional	flxprf,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_lwp,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_ref_liq,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_iwp,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_ref_ice,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_rwp,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_ref_rain,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_swp,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_ref_snow,
		real (kind=kind_phys), dimension(:,:), intent(in), optional	cld_od,
		character(len=*), intent(out)	errmsg,
		integer, intent(out)	errflg
	)

• Change random number seed value for each radiation invocation (isubclw =1 or 2).

• Read surface emissivity.

• Prepare atmospheric profile for use in rrtm.

• Set absorber amount for h2o, co2, and o3.

• Set up column amount for rare gases n2o,ch4,o2,co,ccl4,cf11,cf12, cf22, convert from volume mixing ratio to molec/cm2 based on coldry (scaled to 1.0e-20).

• Set aerosol optical properties.

• Read cloud optical properties.

• Compute precipitable water vapor for diffusivity angle adjustments.

• Compute column amount for broadening gases.

• Compute diffusivity angle adjustments.

• For cloudy atmosphere, call cldprop() to set cloud optical properties.

• Calling setcoef() to compute various coefficients needed in radiative transfer calculations.

• Call taumol() to calculte the gaseous optical depths and Plank fractions for each longwave spectral band.

• Call the radiative transfer routine based on cloud scheme selection. Compute the upward/downward radiative fluxes, and heating rates for both clear or cloudy atmosphere.
  - call rtrn(): clouds are assumed as randomly overlaping in a vertical column
  - call rtrnmr(): clouds are assumed as in maximum-randomly overlaping in a vertical column;
  - call rtrnmc(): clouds are treated with the mcica stochastic approach.

• Save outputs.

Definition at line 419 of file radlw_main.F90.