MODULE calc_radiation_mod !--------------------------------------------------------------------------------! ! This file is part of PALM. ! ! PALM is free software: you can redistribute it and/or modify it under the terms ! of the GNU General Public License as published by the Free Software Foundation, ! either version 3 of the License, or (at your option) any later version. ! ! PALM is distributed in the hope that it will be useful, but WITHOUT ANY ! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR ! A PARTICULAR PURPOSE. See the GNU General Public License for more details. ! ! You should have received a copy of the GNU General Public License along with ! PALM. If not, see . ! ! Copyright 1997-2012 Leibniz University Hannover !--------------------------------------------------------------------------------! ! ! Current revisions: ! ----------------- ! ! ! Former revisions: ! ----------------- ! $Id: calc_radiation.f90 1037 2012-10-22 14:10:22Z witha $ ! ! 1036 2012-10-22 13:43:42Z raasch ! code put under GPL (PALM 3.9) ! ! RCS Log replace by Id keyword, revision history cleaned up ! ! Revision 1.6 2004/01/30 10:17:03 raasch ! Scalar lower k index nzb replaced by 2d-array nzb_2d ! ! Revision 1.1 2000/04/13 14:42:45 schroeter ! Initial revision ! ! ! Description: ! ------------- ! Calculation of the vertical divergences of the long-wave radiation-fluxes ! based on the parameterization of the cloud effective emissivity !------------------------------------------------------------------------------! PRIVATE PUBLIC calc_radiation LOGICAL, SAVE :: first_call = .TRUE. REAL, SAVE :: sigma = 5.67E-08 REAL, DIMENSION(:), ALLOCATABLE, SAVE :: lwp_ground, lwp_top, & blackbody_emission INTERFACE calc_radiation MODULE PROCEDURE calc_radiation MODULE PROCEDURE calc_radiation_ij END INTERFACE calc_radiation CONTAINS !------------------------------------------------------------------------------! ! Call for all grid points !------------------------------------------------------------------------------! SUBROUTINE calc_radiation USE arrays_3d USE cloud_parameters USE control_parameters USE indices USE pegrid IMPLICIT NONE INTEGER :: i, j, k, k_help REAL :: df_p, df_m , effective_emission_up_m, effective_emission_up_p, & effective_emission_down_m, effective_emission_down_p, & f_up_m, f_up_p, f_down_m, f_down_p, impinging_flux_at_top, & temperature ! !-- On first call, allocate temporary arrays IF ( first_call ) THEN ALLOCATE( blackbody_emission(nzb:nzt+1), lwp_ground(nzb:nzt+1), & lwp_top(nzb:nzt+1) ) first_call = .FALSE. ENDIF DO i = nxl, nxr DO j = nys, nyn ! !-- Compute the liquid water path (LWP) and blackbody_emission !-- at all vertical levels lwp_ground(nzb) = 0.0 lwp_top(nzt+1) = rho_surface * ql(nzt+1,j,i) * dzw(nzt+1) temperature = pt(nzb,j,i) * t_d_pt(nzb) + l_d_cp * ql(nzb,j,i) blackbody_emission(nzb) = sigma * temperature**4.0 DO k = nzb_2d(j,i)+1, nzt k_help = ( nzt+nzb+1 ) - k lwp_ground(k) = lwp_ground(k-1) + rho_surface * ql(k,j,i) * & dzw(k) lwp_top(k_help) = lwp_top(k_help+1) + & rho_surface * ql(k_help,j,i) * dzw(k_help) temperature = pt(k,j,i) * t_d_pt(k) + l_d_cp * ql(k,j,i) blackbody_emission(k) = sigma * temperature**4.0 ENDDO lwp_ground(nzt+1) = lwp_ground(nzt) + & rho_surface * ql(nzt+1,j,i) * dzw(nzt+1) lwp_top(nzb) = lwp_top(nzb+1) temperature = pt(nzt+1,j,i) * t_d_pt(nzt+1) + l_d_cp * & ql(nzt+1,j,i) blackbody_emission(nzt+1) = sigma * temperature**4.0 ! !-- See Chlond '92, this is just a first guess impinging_flux_at_top = blackbody_emission(nzb) - 100.0 DO k = nzb_2d(j,i)+1, nzt ! !-- Save some computational time, but this may cause load !-- imbalances if ql is not distributed uniformly IF ( ql(k,j,i) /= 0.0 ) THEN ! !-- Compute effective emissivities effective_emission_up_p = 1.0 - & EXP( -130.0 * lwp_ground(k+1) ) effective_emission_up_m = 1.0 - & EXP( -130.0 * lwp_ground(k-1) ) effective_emission_down_p = 1.0 - & EXP( -158.0 * lwp_top(k+1) ) effective_emission_down_m = 1.0 - & EXP( -158.0 * lwp_top(k-1) ) ! !-- Compute vertical long wave radiation fluxes f_up_p = blackbody_emission(nzb) + & effective_emission_up_p * & ( blackbody_emission(k) - blackbody_emission(nzb) ) f_up_m = blackbody_emission(nzb) + & effective_emission_up_m * & ( blackbody_emission(k-1) - blackbody_emission(nzb) ) f_down_p = impinging_flux_at_top + & effective_emission_down_p * & ( blackbody_emission(k) - impinging_flux_at_top ) f_down_m = impinging_flux_at_top + & effective_emission_down_m * & ( blackbody_emission(k-1) - impinging_flux_at_top ) ! !-- Divergence of vertical long wave radiation fluxes df_p = f_up_p - f_down_p df_m = f_up_m - f_down_m ! !-- Compute tendency term tend(k,j,i) = tend(k,j,i) - & ( pt_d_t(k) / ( rho_surface * cp ) * & ( df_p - df_m ) / dzw(k) ) ENDIF ENDDO ENDDO ENDDO END SUBROUTINE calc_radiation !------------------------------------------------------------------------------! ! Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE calc_radiation_ij( i, j ) USE arrays_3d USE cloud_parameters USE control_parameters USE indices USE pegrid IMPLICIT NONE INTEGER :: i, j, k, k_help REAL :: df_p, df_m , effective_emission_up_m, effective_emission_up_p, & effective_emission_down_m, effective_emission_down_p, & f_up_m, f_up_p, f_down_m, f_down_p, impinging_flux_at_top, & temperature ! !-- On first call, allocate temporary arrays IF ( first_call ) THEN ALLOCATE( blackbody_emission(nzb:nzt+1), lwp_ground(nzb:nzt+1), & lwp_top(nzb:nzt+1) ) first_call = .FALSE. ENDIF ! !-- Compute the liquid water path (LWP) and blackbody_emission !-- at all vertical levels lwp_ground(nzb) = 0.0 lwp_top(nzt+1) = rho_surface * ql(nzt+1,j,i) * dzw(nzt+1) temperature = pt(nzb,j,i) * t_d_pt(nzb) + l_d_cp * ql(nzb,j,i) blackbody_emission(nzb) = sigma * temperature**4.0 DO k = nzb_2d(j,i)+1, nzt k_help = ( nzt+nzb+1 ) - k lwp_ground(k) = lwp_ground(k-1) + rho_surface * ql(k,j,i) * dzw(k) lwp_top(k_help) = lwp_top(k_help+1) + & rho_surface * ql(k_help,j,i) * dzw(k_help) temperature = pt(k,j,i) * t_d_pt(k) + l_d_cp * ql(k,j,i) blackbody_emission(k) = sigma * temperature**4.0 ENDDO lwp_ground(nzt+1) = lwp_ground(nzt) + & rho_surface * ql(nzt+1,j,i) * dzw(nzt+1) lwp_top(nzb) = lwp_top(nzb+1) temperature = pt(nzt+1,j,i) * t_d_pt(nzt+1) + l_d_cp * & ql(nzt+1,j,i) blackbody_emission(nzt+1) = sigma * temperature**4.0 ! !-- See Chlond '92, this is just a first guess impinging_flux_at_top = blackbody_emission(nzb) - 100.0 DO k = nzb_2d(j,i)+1, nzt ! !-- Store some computational time, !-- this may cause load imbalances if ql is not distributed uniformly IF ( ql(k,j,i) /= 0.0 ) THEN ! !-- Compute effective emissivities effective_emission_up_p = 1.0 - & EXP( -130.0 * lwp_ground(k+1) ) effective_emission_up_m = 1.0 - & EXP( -130.0 * lwp_ground(k-1) ) effective_emission_down_p = 1.0 - & EXP( -158.0 * lwp_top(k+1) ) effective_emission_down_m = 1.0 - & EXP( -158.0 * lwp_top(k-1) ) ! !-- Compute vertical long wave radiation fluxes f_up_p = blackbody_emission(nzb) + effective_emission_up_p * & ( blackbody_emission(k) - blackbody_emission(nzb) ) f_up_m = blackbody_emission(nzb) + effective_emission_up_m * & ( blackbody_emission(k-1) - blackbody_emission(nzb) ) f_down_p = impinging_flux_at_top + effective_emission_down_p * & ( blackbody_emission(k) - impinging_flux_at_top ) f_down_m = impinging_flux_at_top + effective_emission_down_m * & ( blackbody_emission(k-1) - impinging_flux_at_top ) ! !- Divergence of vertical long wave radiation fluxes df_p = f_up_p - f_down_p df_m = f_up_m - f_down_m ! !-- Compute tendency term tend(k,j,i) = tend(k,j,i) - ( pt_d_t(k) / ( rho_surface * cp ) * & ( df_p - df_m ) / dzw(k) ) ENDIF ENDDO END SUBROUTINE calc_radiation_ij END MODULE calc_radiation_mod