! radiation_liquid_optics_slingo.F90 - Slingo SW & Lindner-Li LW parameterization of liquid droplet optics ! ! (C) Copyright 2016- ECMWF. ! ! This software is licensed under the terms of the Apache Licence Version 2.0 ! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. ! ! In applying this licence, ECMWF does not waive the privileges and immunities ! granted to it by virtue of its status as an intergovernmental organisation ! nor does it submit to any jurisdiction. ! ! Author: Robin Hogan ! Email: r.j.hogan@ecmwf.int ! module radiation_liquid_optics_slingo implicit none public integer, parameter :: NLiqOpticsCoeffsSlingoSW = 6 integer, parameter :: NLiqOpticsCoeffsLindnerLiLW = 13 contains !--------------------------------------------------------------------- ! Compute liquid-droplet scattering properties in the shortwave from ! Slingo (1989). WARNING: this parameterization is known not to be ! very accurate: see Nielsen et al. (GMD 2014). subroutine calc_liq_optics_slingo(nb, coeff, lwp, re, od, scat_od, g) use parkind1, only : jprb !use yomhook, only : lhook, dr_hook ! Number of bands integer, intent(in) :: nb ! Coefficients read from a data file real(jprb), intent(in) :: coeff(:,:) ! Liquid water path (kg m-2) and effective radius (m) real(jprb), intent(in) :: lwp, re ! Total optical depth, scattering optical depth and asymmetry factor real(jprb), intent(out) :: od(nb), scat_od(nb), g(nb) ! Liquid water path in g m-2 real(jprb) :: lwp_gm_2 ! Effective radius in microns, and its inverse real(jprb) :: re_um, inv_re_um !real(jprb) :: hook_handle !if (lhook) call dr_hook('radiation_liquid_optics_slingo:calc_liq_optics_slingo',0,hook_handle) lwp_gm_2 = lwp * 1000.0_jprb ! Range of validity reported by Slingo (1989): 4.2-16.6 microns re_um = min(max(4.2_jprb, re * 1.0e6_jprb), 16.6_jprb) inv_re_um = 1.0_jprb / re_um od = lwp_gm_2 * (coeff(1:nb,1) + inv_re_um*coeff(1:nb,2)) scat_od = od * (1.0_jprb - coeff(1:nb,3) - re_um*coeff(1:nb,4)) g = coeff(1:nb,5) + re_um*coeff(1:nb,6) !if (lhook) call dr_hook('radiation_liquid_optics_slingo:calc_liq_optics_slingo',1,hook_handle) end subroutine calc_liq_optics_slingo !--------------------------------------------------------------------- ! Compute liquid-droplet scattering properties in the longwave from ! Lindner & Li (2000) subroutine calc_liq_optics_lindner_li(nb, coeff, lwp, re, od, scat_od, g) use parkind1, only : jprb use yomhook, only : lhook, dr_hook ! Number of bands integer, intent(in) :: nb ! Coefficients read from a data file real(jprb), intent(in) :: coeff(:,:) ! Liquid water path (kg m-2) and effective radius (m) real(jprb), intent(in) :: lwp, re ! Total optical depth, scattering optical depth and asymmetry factor real(jprb), intent(out) :: od(nb), scat_od(nb), g(nb) ! Liquid water path in g m-2 real(jprb) :: lwp_gm_2 ! Effective radius in microns, and its inverse real(jprb) :: re_um, inv_re_um real(jprb) :: hook_handle if (lhook) call dr_hook('radiation_liquid_optics_slingo:calc_liq_optics_lindner_li',0,hook_handle) lwp_gm_2 = lwp * 1000.0_jprb ! Range of validity reported by Lindner and Li (2000): 2-40 microns re_um = min(max(2.0_jprb, re * 1.0e6_jprb), 40.0_jprb) inv_re_um = 1.0_jprb / re_um od = lwp_gm_2 * (coeff(1:nb,1) + re_um*coeff(1:nb,2) + inv_re_um*(coeff(1:nb,3) & & + inv_re_um*(coeff(1:nb,4) + inv_re_um*coeff(1:nb,5)))) scat_od = od * (1.0_jprb - (coeff(1:nb,6) + inv_re_um*coeff(1:nb,7) & & + re_um*(coeff(1:nb,8) + re_um*coeff(1:nb,9)))) g = coeff(1:nb,10) + inv_re_um*coeff(1:nb,11) & & + re_um*(coeff(1:nb,12) + re_um*coeff(1:nb,13)) if (lhook) call dr_hook('radiation_liquid_optics_slingo:calc_liq_optics_lindner_li',1,hook_handle) end subroutine calc_liq_optics_lindner_li end module radiation_liquid_optics_slingo