[3908] | 1 | ! radiation_ice_optics_yi.F90 - Yi et al. (2013) ice optical properties |
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| 2 | ! |
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| 3 | ! (C) Copyright 2017- ECMWF. |
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| 4 | ! |
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| 5 | ! This software is licensed under the terms of the Apache Licence Version 2.0 |
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| 6 | ! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. |
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| 7 | ! |
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| 8 | ! In applying this licence, ECMWF does not waive the privileges and immunities |
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| 9 | ! granted to it by virtue of its status as an intergovernmental organisation |
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| 10 | ! nor does it submit to any jurisdiction. |
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| 11 | ! |
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| 12 | ! Authors: Mark Fielding and Robin Hogan |
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| 13 | ! Email: r.j.hogan@ecmwf.int |
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| 14 | ! |
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| 15 | ! The reference for this ice optics parameterization is Yi, B., |
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| 16 | ! P. Yang, B.A. Baum, T. L'Ecuyer, L. Oreopoulos, E.J. Mlawer, |
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| 17 | ! A.J. Heymsfield, and K. Liou, 2013: Influence of Ice Particle |
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| 18 | ! Surface Roughening on the Global Cloud Radiative |
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| 19 | ! Effect. J. Atmos. Sci., 70, 2794–2807, |
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| 20 | ! https://doi.org/10.1175/JAS-D-13-020.1 |
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| 21 | |
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| 22 | module radiation_ice_optics_yi |
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| 23 | |
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| 24 | implicit none |
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| 25 | public |
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| 26 | |
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| 27 | ! The number of ice coefficients depends on the parameterization |
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| 28 | integer, parameter :: NIceOpticsCoeffsYiSW = 69 |
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| 29 | integer, parameter :: NIceOpticsCoeffsYiLW = 69 |
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| 30 | |
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| 31 | integer, parameter :: NSingleCoeffs = 23 |
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| 32 | |
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| 33 | contains |
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| 34 | |
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| 35 | !--------------------------------------------------------------------- |
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| 36 | ! Compute shortwave ice-particle scattering properties using Yi et |
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| 37 | ! al. (2013) parameterization |
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| 38 | subroutine calc_ice_optics_yi_sw(nb, coeff, ice_wp, & |
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| 39 | & re, od, scat_od, g) |
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| 40 | |
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| 41 | use parkind1, only : jprb, jpim |
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| 42 | !use yomhook, only : lhook, dr_hook |
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| 43 | |
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| 44 | ! Number of bands |
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| 45 | integer, intent(in) :: nb |
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| 46 | ! Coefficients read from a data file |
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| 47 | real(jprb), intent(in) :: coeff(:,:) |
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| 48 | ! Ice water path (kg m-2) |
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| 49 | real(jprb), intent(in) :: ice_wp |
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| 50 | ! Effective radius (m) |
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| 51 | real(jprb), intent(in) :: re |
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| 52 | ! Total optical depth, scattering optical depth and asymmetry factor |
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| 53 | real(jprb), intent(out) :: od(nb), scat_od(nb), g(nb) |
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| 54 | |
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| 55 | ! Yi's effective diameter (microns) |
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| 56 | real(jprb) :: de_um |
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| 57 | ! Ice water path in g m-2 |
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| 58 | real (jprb) :: iwp_gm_2 |
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| 59 | ! LUT temp variables |
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| 60 | real(jprb) :: wts_1, wts_2 |
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| 61 | integer(jpim) :: lu_idx |
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| 62 | real(kind=jprb), parameter :: lu_scale = 0.2_jprb |
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| 63 | real(kind=jprb), parameter :: lu_offset = 1.0_jprb |
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| 64 | !real(jprb) :: hook_handle |
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| 65 | |
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| 66 | !if (lhook) call dr_hook('radiation_ice_optics:calc_ice_optics_yi_sw',0,hook_handle) |
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| 67 | |
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| 68 | ! Convert to effective diameter using the relationship in the IFS |
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| 69 | !de_um = re * (1.0e6_jprb / 0.64952_jprb) |
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| 70 | de_um = re * 2.0e6_jprb |
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| 71 | |
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| 72 | ! limit de_um to validity of LUT |
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| 73 | de_um = max(de_um,10.0_jprb) |
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| 74 | de_um = min(de_um,119.99_jprb) !avoid greater than or equal to 120 um |
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| 75 | |
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| 76 | iwp_gm_2 = ice_wp * 1000.0_jprb |
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| 77 | |
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| 78 | lu_idx = floor(de_um * lu_scale - lu_offset) |
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| 79 | wts_2 = (de_um * lu_scale - lu_offset) - lu_idx |
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| 80 | wts_1 = 1.0_jprb - wts_2 |
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| 81 | od = 0.001_jprb * iwp_gm_2 * & |
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| 82 | & ( wts_1 * coeff(1:nb,lu_idx) + wts_2 * coeff(1:nb,lu_idx+1) ) |
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| 83 | scat_od = od * & |
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| 84 | & ( wts_1 * coeff(1:nb,lu_idx+NSingleCoeffs) + wts_2 * coeff(1:nb,lu_idx+NSingleCoeffs+1) ) |
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| 85 | g = wts_1 * coeff(1:nb,lu_idx+2*NSingleCoeffs) + wts_2 * coeff(1:nb,lu_idx+2*NSingleCoeffs+1) |
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| 86 | |
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| 87 | !if (lhook) call dr_hook('radiation_ice_optics:calc_ice_optics_yi_sw',1,hook_handle) |
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| 88 | |
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| 89 | end subroutine calc_ice_optics_yi_sw |
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| 90 | |
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| 91 | |
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| 92 | !--------------------------------------------------------------------- |
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| 93 | ! Compute longwave ice-particle scattering properties using Yi et |
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| 94 | ! al. (2013) parameterization |
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| 95 | subroutine calc_ice_optics_yi_lw(nb, coeff, ice_wp, & |
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| 96 | & re, od, scat_od, g) |
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| 97 | |
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| 98 | use parkind1, only : jprb, jpim |
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| 99 | !use yomhook, only : lhook, dr_hook |
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| 100 | |
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| 101 | ! Number of bands |
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| 102 | integer, intent(in) :: nb |
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| 103 | ! Coefficients read from a data file |
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| 104 | real(jprb), intent(in) :: coeff(:,:) |
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| 105 | ! Ice water path (kg m-2) |
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| 106 | real(jprb), intent(in) :: ice_wp |
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| 107 | ! Effective radius (m) |
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| 108 | real(jprb), intent(in) :: re |
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| 109 | ! Total optical depth, scattering optical depth and asymmetry factor |
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| 110 | real(jprb), intent(out) :: od(nb), scat_od(nb), g(nb) |
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| 111 | |
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| 112 | ! Yi's effective diameter (microns) |
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| 113 | real(jprb) :: de_um |
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| 114 | ! Ice water path in g m-2 |
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| 115 | real (jprb) :: iwp_gm_2 |
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| 116 | ! LUT temp variables |
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| 117 | real(jprb) :: wts_1, wts_2 |
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| 118 | integer(jpim) :: lu_idx |
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| 119 | real(kind=jprb), parameter :: lu_scale = 0.2_jprb |
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| 120 | real(kind=jprb), parameter :: lu_offset = 1.0_jprb |
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| 121 | !real(jprb) :: hook_handle |
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| 122 | |
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| 123 | !if (lhook) call dr_hook('radiation_ice_optics:calc_ice_optics_yi_sw',0,hook_handle) |
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| 124 | |
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| 125 | ! Convert to effective diameter using the relationship in the IFS |
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| 126 | !de_um = re * (1.0e6_jprb / 0.64952_jprb) |
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| 127 | de_um = re * 2.0e6_jprb |
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| 128 | |
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| 129 | ! limit de_um to validity of LUT |
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| 130 | de_um = max(de_um,10.0_jprb) |
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| 131 | de_um = min(de_um,119.99_jprb) !avoid greater than or equal to 120 um |
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| 132 | |
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| 133 | iwp_gm_2 = ice_wp * 1000.0_jprb |
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| 134 | |
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| 135 | lu_idx = floor(de_um * lu_scale - lu_offset) |
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| 136 | wts_2 = (de_um * lu_scale - lu_offset) - lu_idx |
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| 137 | wts_1 = 1.0_jprb - wts_2 |
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| 138 | od = 0.001_jprb * iwp_gm_2 * & |
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| 139 | & ( wts_1 * coeff(1:nb,lu_idx) + wts_2 * coeff(1:nb,lu_idx+1) ) |
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| 140 | scat_od = od * & |
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| 141 | & ( wts_1 * coeff(1:nb,lu_idx+NSingleCoeffs) + wts_2 * coeff(1:nb,lu_idx+NSingleCoeffs+1) ) |
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| 142 | g = wts_1 * coeff(1:nb,lu_idx+2*NSingleCoeffs) + wts_2 * coeff(1:nb,lu_idx+2*NSingleCoeffs+1) |
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| 143 | |
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| 144 | !if (lhook) call dr_hook('radiation_ice_optics:calc_ice_optics_yi_lw',1,hook_handle) |
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| 145 | |
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| 146 | end subroutine calc_ice_optics_yi_lw |
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| 147 | |
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| 148 | end module radiation_ice_optics_yi |
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