!> @file microphysics_mod.f90 !--------------------------------------------------------------------------------! ! 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 1997-2016 Leibniz Universitaet Hannover !--------------------------------------------------------------------------------! ! ! Current revisions: ! ------------------ ! ! ! Former revisions: ! ----------------- ! $Id: microphysics_mod.f90 1851 2016-04-08 13:32:50Z hoffmann $ ! ! 1850 2016-04-08 13:29:27Z maronga ! Module renamed ! Adapted for modularization of microphysics. ! ! 1845 2016-04-08 08:29:13Z raasch ! nzb_2d replaced by nzb_s_inner, Kessler precipitation is stored at surface ! point (instead of one point above surface) ! ! 1831 2016-04-07 13:15:51Z hoffmann ! turbulence renamed collision_turbulence, ! drizzle renamed cloud_water_sedimentation. cloud_water_sedimentation also ! avaialble for microphysics_kessler. ! ! 1822 2016-04-07 07:49:42Z hoffmann ! Unused variables removed. ! Kessler scheme integrated. ! ! 1691 2015-10-26 16:17:44Z maronga ! Added new routine calc_precipitation_amount. The routine now allows to account ! for precipitation due to sedimenation of cloud (fog) droplets ! ! 1682 2015-10-07 23:56:08Z knoop ! Code annotations made doxygen readable ! ! 1646 2015-09-02 16:00:10Z hoffmann ! Bugfix: Wrong computation of d_mean. ! ! 1361 2014-04-16 15:17:48Z hoffmann ! Bugfix in sedimentation_rain: Index corrected. ! Vectorized version of adjust_cloud added. ! Little reformatting of the code. ! ! 1353 2014-04-08 15:21:23Z heinze ! REAL constants provided with KIND-attribute ! ! 1346 2014-03-27 13:18:20Z heinze ! Bugfix: REAL constants provided with KIND-attribute especially in call of ! intrinsic function like MAX, MIN, SIGN ! ! 1334 2014-03-25 12:21:40Z heinze ! Bugfix: REAL constants provided with KIND-attribute ! ! 1322 2014-03-20 16:38:49Z raasch ! REAL constants defined as wp-kind ! ! 1320 2014-03-20 08:40:49Z raasch ! ONLY-attribute added to USE-statements, ! kind-parameters added to all INTEGER and REAL declaration statements, ! kinds are defined in new module kinds, ! comment fields (!:) to be used for variable explanations added to ! all variable declaration statements ! ! 1241 2013-10-30 11:36:58Z heinze ! hyp and rho have to be calculated at each time step if data from external ! file LSF_DATA are used ! ! 1115 2013-03-26 18:16:16Z hoffmann ! microphyical tendencies are calculated in microphysics_control in an optimized ! way; unrealistic values are prevented; bugfix in evaporation; some reformatting ! ! 1106 2013-03-04 05:31:38Z raasch ! small changes in code formatting ! ! 1092 2013-02-02 11:24:22Z raasch ! unused variables removed ! file put under GPL ! ! 1065 2012-11-22 17:42:36Z hoffmann ! Sedimentation process implemented according to Stevens and Seifert (2008). ! Turbulence effects on autoconversion and accretion added (Seifert, Nuijens ! and Stevens, 2010). ! ! 1053 2012-11-13 17:11:03Z hoffmann ! initial revision ! ! Description: ! ------------ !> Calculate bilk cloud microphysics. !------------------------------------------------------------------------------! MODULE microphysics_mod USE kinds IMPLICIT NONE LOGICAL :: cloud_water_sedimentation = .FALSE. !< cloud water sedimentation LOGICAL :: limiter_sedimentation = .TRUE. !< sedimentation limiter LOGICAL :: collision_turbulence = .FALSE. !< turbulence effects LOGICAL :: ventilation_effect = .TRUE. !< ventilation effect REAL(wp) :: a_1 = 8.69E-4_wp !< coef. in turb. parametrization (cm-2 s3) REAL(wp) :: a_2 = -7.38E-5_wp !< coef. in turb. parametrization (cm-2 s3) REAL(wp) :: a_3 = -1.40E-2_wp !< coef. in turb. parametrization REAL(wp) :: a_term = 9.65_wp !< coef. for terminal velocity (m s-1) REAL(wp) :: a_vent = 0.78_wp !< coef. for ventilation effect REAL(wp) :: b_1 = 11.45E-6_wp !< coef. in turb. parametrization (m) REAL(wp) :: b_2 = 9.68E-6_wp !< coef. in turb. parametrization (m) REAL(wp) :: b_3 = 0.62_wp !< coef. in turb. parametrization REAL(wp) :: b_term = 9.8_wp !< coef. for terminal velocity (m s-1) REAL(wp) :: b_vent = 0.308_wp !< coef. for ventilation effect REAL(wp) :: beta_cc = 3.09E-4_wp !< coef. in turb. parametrization (cm-2 s3) REAL(wp) :: c_1 = 4.82E-6_wp !< coef. in turb. parametrization (m) REAL(wp) :: c_2 = 4.8E-6_wp !< coef. in turb. parametrization (m) REAL(wp) :: c_3 = 0.76_wp !< coef. in turb. parametrization REAL(wp) :: c_const = 0.93_wp !< const. in Taylor-microscale Reynolds number REAL(wp) :: c_evap = 0.7_wp !< constant in evaporation REAL(wp) :: c_term = 600.0_wp !< coef. for terminal velocity (m-1) REAL(wp) :: diff_coeff_l = 0.23E-4_wp !< diffusivity of water vapor (m2 s-1) REAL(wp) :: eps_sb = 1.0E-20_wp !< threshold in two-moments scheme REAL(wp) :: k_cc = 9.44E09_wp !< const. cloud-cloud kernel (m3 kg-2 s-1) REAL(wp) :: k_cr0 = 4.33_wp !< const. cloud-rain kernel (m3 kg-1 s-1) REAL(wp) :: k_rr = 7.12_wp !< const. rain-rain kernel (m3 kg-1 s-1) REAL(wp) :: k_br = 1000.0_wp !< const. in breakup parametrization (m-1) REAL(wp) :: k_st = 1.2E8_wp !< const. in drizzle parametrization (m-1 s-1) REAL(wp) :: kappa_rr = 60.7_wp !< const. in collision kernel (kg-1/3) REAL(wp) :: kin_vis_air = 1.4086E-5_wp !< kin. viscosity of air (m2 s-1) REAL(wp) :: prec_time_const = 0.001_wp !< coef. in Kessler scheme (s-1) REAL(wp) :: ql_crit = 0.0005_wp !< coef. in Kessler scheme (kg kg-1) REAL(wp) :: schmidt_p_1d3=0.8921121_wp !< Schmidt number**0.33333, 0.71**0.33333 REAL(wp) :: sigma_gc = 1.3_wp !< geometric standard deviation cloud droplets REAL(wp) :: thermal_conductivity_l = 2.43E-2_wp !< therm. cond. air (J m-1 s-1 K-1) REAL(wp) :: w_precipitation = 9.65_wp !< maximum terminal velocity (m s-1) REAL(wp) :: x0 = 2.6E-10_wp !< separating drop mass (kg) REAL(wp) :: xrmin = 2.6E-10_wp !< minimum rain drop size (kg) REAL(wp) :: xrmax = 5.0E-6_wp !< maximum rain drop site (kg) REAL(wp) :: c_sedimentation = 2.0_wp !< Courant number of sedimentation process REAL(wp) :: dpirho_l !< 6.0 / ( pi * rho_l ) REAL(wp) :: dt_micro !< microphysics time step REAL(wp) :: nc_const = 70.0E6_wp !< cloud droplet concentration REAL(wp) :: dt_precipitation = 100.0_wp !< timestep precipitation (s) REAL(wp) :: sed_qc_const !< const. for sedimentation of cloud water REAL(wp) :: pirho_l !< pi * rho_l / 6.0; REAL(wp), DIMENSION(:), ALLOCATABLE :: nc_1d !< REAL(wp), DIMENSION(:), ALLOCATABLE :: nr_1d !< REAL(wp), DIMENSION(:), ALLOCATABLE :: pt_1d !< REAL(wp), DIMENSION(:), ALLOCATABLE :: qc_1d !< REAL(wp), DIMENSION(:), ALLOCATABLE :: qr_1d !< REAL(wp), DIMENSION(:), ALLOCATABLE :: q_1d !< SAVE PRIVATE PUBLIC microphysics_control, microphysics_init PUBLIC cloud_water_sedimentation, collision_turbulence, c_sedimentation, & dt_precipitation, limiter_sedimentation, nc_const, sigma_gc, & ventilation_effect INTERFACE microphysics_control MODULE PROCEDURE microphysics_control MODULE PROCEDURE microphysics_control_ij END INTERFACE microphysics_control INTERFACE adjust_cloud MODULE PROCEDURE adjust_cloud MODULE PROCEDURE adjust_cloud_ij END INTERFACE adjust_cloud INTERFACE autoconversion MODULE PROCEDURE autoconversion MODULE PROCEDURE autoconversion_ij END INTERFACE autoconversion INTERFACE autoconversion_kessler MODULE PROCEDURE autoconversion_kessler MODULE PROCEDURE autoconversion_kessler_ij END INTERFACE autoconversion_kessler INTERFACE accretion MODULE PROCEDURE accretion MODULE PROCEDURE accretion_ij END INTERFACE accretion INTERFACE selfcollection_breakup MODULE PROCEDURE selfcollection_breakup MODULE PROCEDURE selfcollection_breakup_ij END INTERFACE selfcollection_breakup INTERFACE evaporation_rain MODULE PROCEDURE evaporation_rain MODULE PROCEDURE evaporation_rain_ij END INTERFACE evaporation_rain INTERFACE sedimentation_cloud MODULE PROCEDURE sedimentation_cloud MODULE PROCEDURE sedimentation_cloud_ij END INTERFACE sedimentation_cloud INTERFACE sedimentation_rain MODULE PROCEDURE sedimentation_rain MODULE PROCEDURE sedimentation_rain_ij END INTERFACE sedimentation_rain INTERFACE calc_precipitation_amount MODULE PROCEDURE calc_precipitation_amount MODULE PROCEDURE calc_precipitation_amount_ij END INTERFACE calc_precipitation_amount CONTAINS !------------------------------------------------------------------------------! ! Description: ! ------------ !> Initialization of bulk microphysics !------------------------------------------------------------------------------! SUBROUTINE microphysics_init USE arrays_3d, & ONLY: dzu USE constants, & ONLY: pi USE cloud_parameters, & ONLY: rho_l USE control_parameters, & ONLY: microphysics_seifert USE indices, & ONLY: nzb, nzt IMPLICIT NONE ! !-- constant for the sedimentation of cloud water (2-moment cloud physics) sed_qc_const = k_st * ( 3.0_wp / ( 4.0_wp * pi * rho_l ) & )**( 2.0_wp / 3.0_wp ) * & EXP( 5.0_wp * LOG( sigma_gc )**2 ) ! !-- Calculate timestep according to precipitation IF ( microphysics_seifert ) THEN dt_precipitation = c_sedimentation * MINVAL( dzu(nzb+2:nzt) ) / & w_precipitation ENDIF ! !-- Pre-calculate frequently calculated fractions of pi and rho_l pirho_l = pi * rho_l / 6.0_wp dpirho_l = 1.0_wp / pirho_l ! !-- Allocate 1D microphysics arrays ALLOCATE ( nc_1d(nzb:nzt+1), pt_1d(nzb:nzt+1), q_1d(nzb:nzt+1), & qc_1d(nzb:nzt+1) ) IF ( microphysics_seifert ) THEN ALLOCATE ( nr_1d(nzb:nzt+1), qr_1d(nzb:nzt+1) ) ENDIF ! !-- Initialze nc_1d with nc_const nc_1d = nc_const END SUBROUTINE microphysics_init !------------------------------------------------------------------------------! ! Description: ! ------------ !> Control of microphysics for all grid points !------------------------------------------------------------------------------! SUBROUTINE microphysics_control USE arrays_3d, & ONLY: hyp, pt_init, prr, zu USE cloud_parameters, & ONLY: cp, hyrho, pt_d_t, r_d, t_d_pt USE control_parameters, & ONLY: call_microphysics_at_all_substeps, dt_3d, g, & intermediate_timestep_count, large_scale_forcing, & lsf_surf, microphysics_kessler, microphysics_seifert, & pt_surface, rho_surface,surface_pressure USE indices, & ONLY: nzb, nzt USE kinds USE statistics, & ONLY: weight_pres IMPLICIT NONE INTEGER(iwp) :: k !< REAL(wp) :: t_surface !< IF ( large_scale_forcing .AND. lsf_surf ) THEN ! !-- Calculate: !-- pt / t : ratio of potential and actual temperature (pt_d_t) !-- t / pt : ratio of actual and potential temperature (t_d_pt) !-- p_0(z) : vertical profile of the hydrostatic pressure (hyp) t_surface = pt_surface * ( surface_pressure / 1000.0_wp )**0.286_wp DO k = nzb, nzt+1 hyp(k) = surface_pressure * 100.0_wp * & ( ( t_surface - g / cp * zu(k) ) / & t_surface )**(1.0_wp / 0.286_wp) pt_d_t(k) = ( 100000.0_wp / hyp(k) )**0.286_wp t_d_pt(k) = 1.0_wp / pt_d_t(k) hyrho(k) = hyp(k) / ( r_d * t_d_pt(k) * pt_init(k) ) ENDDO ! !-- Compute reference density rho_surface = surface_pressure * 100.0_wp / ( r_d * t_surface ) ENDIF ! !-- Compute length of time step IF ( call_microphysics_at_all_substeps ) THEN dt_micro = dt_3d * weight_pres(intermediate_timestep_count) ELSE dt_micro = dt_3d ENDIF ! !-- Reset precipitation rate IF ( intermediate_timestep_count == 1 ) prr = 0.0_wp ! !-- Compute cloud physics IF ( microphysics_kessler ) THEN CALL autoconversion_kessler IF ( cloud_water_sedimentation ) CALL sedimentation_cloud ELSEIF ( microphysics_seifert ) THEN CALL adjust_cloud CALL autoconversion CALL accretion CALL selfcollection_breakup CALL evaporation_rain CALL sedimentation_rain IF ( cloud_water_sedimentation ) CALL sedimentation_cloud ENDIF CALL calc_precipitation_amount END SUBROUTINE microphysics_control !------------------------------------------------------------------------------! ! Description: ! ------------ !> Adjust number of raindrops to avoid nonlinear effects in sedimentation and !> evaporation of rain drops due to too small or too big weights !> of rain drops (Stevens and Seifert, 2008). !------------------------------------------------------------------------------! SUBROUTINE adjust_cloud USE arrays_3d, & ONLY: qr, nr USE cloud_parameters, & ONLY: hyrho USE cpulog, & ONLY: cpu_log, log_point_s USE indices, & ONLY: nxl, nxr, nys, nyn, nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< CALL cpu_log( log_point_s(54), 'adjust_cloud', 'start' ) DO i = nxl, nxr DO j = nys, nyn DO k = nzb_s_inner(j,i)+1, nzt IF ( qr(k,j,i) <= eps_sb ) THEN qr(k,j,i) = 0.0_wp nr(k,j,i) = 0.0_wp ELSE IF ( nr(k,j,i) * xrmin > qr(k,j,i) * hyrho(k) ) THEN nr(k,j,i) = qr(k,j,i) * hyrho(k) / xrmin ELSEIF ( nr(k,j,i) * xrmax < qr(k,j,i) * hyrho(k) ) THEN nr(k,j,i) = qr(k,j,i) * hyrho(k) / xrmax ENDIF ENDIF ENDDO ENDDO ENDDO CALL cpu_log( log_point_s(54), 'adjust_cloud', 'stop' ) END SUBROUTINE adjust_cloud !------------------------------------------------------------------------------! ! Description: ! ------------ !> Autoconversion rate (Seifert and Beheng, 2006). !------------------------------------------------------------------------------! SUBROUTINE autoconversion USE arrays_3d, & ONLY: diss, dzu, nr, qc, qr USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: rho_surface USE cpulog, & ONLY: cpu_log, log_point_s USE grid_variables, & ONLY: dx, dy USE indices, & ONLY: nxl, nxr, nys, nyn, nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: alpha_cc !< REAL(wp) :: autocon !< REAL(wp) :: dissipation !< REAL(wp) :: k_au !< REAL(wp) :: l_mix !< REAL(wp) :: nu_c !< REAL(wp) :: phi_au !< REAL(wp) :: r_cc !< REAL(wp) :: rc !< REAL(wp) :: re_lambda !< REAL(wp) :: sigma_cc !< REAL(wp) :: tau_cloud !< REAL(wp) :: xc !< CALL cpu_log( log_point_s(55), 'autoconversion', 'start' ) DO i = nxl, nxr DO j = nys, nyn DO k = nzb_s_inner(j,i)+1, nzt IF ( qc(k,j,i) > eps_sb ) THEN k_au = k_cc / ( 20.0_wp * x0 ) ! !-- Intern time scale of coagulation (Seifert and Beheng, 2006): !-- (1.0_wp - qc(k,j,i) / ( qc(k,j,i) + qr(k,j,i) )) tau_cloud = 1.0_wp - qc(k,j,i) / ( qr(k,j,i) + qc(k,j,i) ) ! !-- Universal function for autoconversion process !-- (Seifert and Beheng, 2006): phi_au = 600.0_wp * tau_cloud**0.68_wp * & ( 1.0_wp - tau_cloud**0.68_wp )**3 ! !-- Shape parameter of gamma distribution (Geoffroy et al., 2010): !-- (Use constant nu_c = 1.0_wp instead?) nu_c = 1.0_wp !MAX( 0.0_wp, 1580.0_wp * hyrho(k) * qc(k,j,i) - 0.28_wp ) ! !-- Mean weight of cloud droplets: xc = hyrho(k) * qc(k,j,i) / nc_const ! !-- Parameterized turbulence effects on autoconversion (Seifert, !-- Nuijens and Stevens, 2010) IF ( collision_turbulence ) THEN ! !-- Weight averaged radius of cloud droplets: rc = 0.5_wp * ( xc * dpirho_l )**( 1.0_wp / 3.0_wp ) alpha_cc = ( a_1 + a_2 * nu_c ) / ( 1.0_wp + a_3 * nu_c ) r_cc = ( b_1 + b_2 * nu_c ) / ( 1.0_wp + b_3 * nu_c ) sigma_cc = ( c_1 + c_2 * nu_c ) / ( 1.0_wp + c_3 * nu_c ) ! !-- Mixing length (neglecting distance to ground and !-- stratification) l_mix = ( dx * dy * dzu(k) )**( 1.0_wp / 3.0_wp ) ! !-- Limit dissipation rate according to Seifert, Nuijens and !-- Stevens (2010) dissipation = MIN( 0.06_wp, diss(k,j,i) ) ! !-- Compute Taylor-microscale Reynolds number: re_lambda = 6.0_wp / 11.0_wp * & ( l_mix / c_const )**( 2.0_wp / 3.0_wp ) * & SQRT( 15.0_wp / kin_vis_air ) * & dissipation**( 1.0_wp / 6.0_wp ) ! !-- The factor of 1.0E4 is needed to convert the dissipation !-- rate from m2 s-3 to cm2 s-3. k_au = k_au * ( 1.0_wp + & dissipation * 1.0E4_wp * & ( re_lambda * 1.0E-3_wp )**0.25_wp * & ( alpha_cc * EXP( -1.0_wp * ( ( rc - & r_cc ) / & sigma_cc )**2 & ) + beta_cc & ) & ) ENDIF ! !-- Autoconversion rate (Seifert and Beheng, 2006): autocon = k_au * ( nu_c + 2.0_wp ) * ( nu_c + 4.0_wp ) / & ( nu_c + 1.0_wp )**2 * qc(k,j,i)**2 * xc**2 * & ( 1.0_wp + phi_au / ( 1.0_wp - tau_cloud )**2 ) * & rho_surface autocon = MIN( autocon, qc(k,j,i) / dt_micro ) qr(k,j,i) = qr(k,j,i) + autocon * dt_micro qc(k,j,i) = qc(k,j,i) - autocon * dt_micro nr(k,j,i) = nr(k,j,i) + autocon / x0 * hyrho(k) * dt_micro ENDIF ENDDO ENDDO ENDDO CALL cpu_log( log_point_s(55), 'autoconversion', 'stop' ) END SUBROUTINE autoconversion !------------------------------------------------------------------------------! ! Description: ! ------------ !> Autoconversion process (Kessler, 1969). !------------------------------------------------------------------------------! SUBROUTINE autoconversion_kessler USE arrays_3d, & ONLY: dzw, pt, prr, q, qc USE cloud_parameters, & ONLY: l_d_cp, pt_d_t USE indices, & ONLY: nxl, nxr, nyn, nys, nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: dqdt_precip !< DO i = nxl, nxr DO j = nys, nyn DO k = nzb_s_inner(j,i)+1, nzt IF ( qc(k,j,i) > ql_crit ) THEN dqdt_precip = prec_time_const * ( qc(k,j,i) - ql_crit ) ELSE dqdt_precip = 0.0_wp ENDIF qc(k,j,i) = qc(k,j,i) - dqdt_precip * dt_micro q(k,j,i) = q(k,j,i) - dqdt_precip * dt_micro pt(k,j,i) = pt(k,j,i) + dqdt_precip * dt_micro * l_d_cp * & pt_d_t(k) ! !-- Compute the rain rate (stored on surface grid point) prr(nzb_s_inner(j,i),j,i) = prr(nzb_s_inner(j,i),j,i) + & dqdt_precip * dzw(k) ENDDO ENDDO ENDDO END SUBROUTINE autoconversion_kessler !------------------------------------------------------------------------------! ! Description: ! ------------ !> Accretion rate (Seifert and Beheng, 2006). !------------------------------------------------------------------------------! SUBROUTINE accretion USE arrays_3d, & ONLY: diss, qc, qr USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: rho_surface USE cpulog, & ONLY: cpu_log, log_point_s USE indices, & ONLY: nxl, nxr, nys, nyn, nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: accr !< REAL(wp) :: k_cr !< REAL(wp) :: phi_ac !< REAL(wp) :: tau_cloud !< CALL cpu_log( log_point_s(56), 'accretion', 'start' ) DO i = nxl, nxr DO j = nys, nyn DO k = nzb_s_inner(j,i)+1, nzt IF ( ( qc(k,j,i) > eps_sb ) .AND. ( qr(k,j,i) > eps_sb ) ) THEN ! !-- Intern time scale of coagulation (Seifert and Beheng, 2006): tau_cloud = 1.0_wp - qc(k,j,i) / ( qc(k,j,i) + qr(k,j,i) ) ! !-- Universal function for accretion process (Seifert and !-- Beheng, 2001): phi_ac = ( tau_cloud / ( tau_cloud + 5.0E-5_wp ) )**4 ! !-- Parameterized turbulence effects on autoconversion (Seifert, !-- Nuijens and Stevens, 2010). The factor of 1.0E4 is needed to !-- convert the dissipation rate (diss) from m2 s-3 to cm2 s-3. IF ( collision_turbulence ) THEN k_cr = k_cr0 * ( 1.0_wp + 0.05_wp * & MIN( 600.0_wp, & diss(k,j,i) * 1.0E4_wp )**0.25_wp & ) ELSE k_cr = k_cr0 ENDIF ! !-- Accretion rate (Seifert and Beheng, 2006): accr = k_cr * qc(k,j,i) * qr(k,j,i) * phi_ac * & SQRT( rho_surface * hyrho(k) ) accr = MIN( accr, qc(k,j,i) / dt_micro ) qr(k,j,i) = qr(k,j,i) + accr * dt_micro qc(k,j,i) = qc(k,j,i) - accr * dt_micro ENDIF ENDDO ENDDO ENDDO CALL cpu_log( log_point_s(56), 'accretion', 'stop' ) END SUBROUTINE accretion !------------------------------------------------------------------------------! ! Description: ! ------------ !> Collisional breakup rate (Seifert, 2008). !------------------------------------------------------------------------------! SUBROUTINE selfcollection_breakup USE arrays_3d, & ONLY: nr, qr USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: rho_surface USE cpulog, & ONLY: cpu_log, log_point_s USE indices, & ONLY: nxl, nxr, nys, nyn, nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: breakup !< REAL(wp) :: dr !< REAL(wp) :: phi_br !< REAL(wp) :: selfcoll !< CALL cpu_log( log_point_s(57), 'selfcollection', 'start' ) DO i = nxl, nxr DO j = nys, nyn DO k = nzb_s_inner(j,i)+1, nzt IF ( qr(k,j,i) > eps_sb ) THEN ! !-- Selfcollection rate (Seifert and Beheng, 2001): selfcoll = k_rr * nr(k,j,i) * qr(k,j,i) * & SQRT( hyrho(k) * rho_surface ) ! !-- Weight averaged diameter of rain drops: dr = ( hyrho(k) * qr(k,j,i) / & nr(k,j,i) * dpirho_l )**( 1.0_wp / 3.0_wp ) ! !-- Collisional breakup rate (Seifert, 2008): IF ( dr >= 0.3E-3_wp ) THEN phi_br = k_br * ( dr - 1.1E-3_wp ) breakup = selfcoll * ( phi_br + 1.0_wp ) ELSE breakup = 0.0_wp ENDIF selfcoll = MAX( breakup - selfcoll, -nr(k,j,i) / dt_micro ) nr(k,j,i) = nr(k,j,i) + selfcoll * dt_micro ENDIF ENDDO ENDDO ENDDO CALL cpu_log( log_point_s(57), 'selfcollection', 'stop' ) END SUBROUTINE selfcollection_breakup !------------------------------------------------------------------------------! ! Description: ! ------------ !> Evaporation of precipitable water. Condensation is neglected for !> precipitable water. !------------------------------------------------------------------------------! SUBROUTINE evaporation_rain USE arrays_3d, & ONLY: hyp, nr, pt, q, qc, qr USE cloud_parameters, & ONLY: hyrho, l_d_cp, l_d_r, l_v, r_v, t_d_pt USE constants, & ONLY: pi USE cpulog, & ONLY: cpu_log, log_point_s USE indices, & ONLY: nxl, nxr, nys, nyn, nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: alpha !< REAL(wp) :: dr !< REAL(wp) :: e_s !< REAL(wp) :: evap !< REAL(wp) :: evap_nr !< REAL(wp) :: f_vent !< REAL(wp) :: g_evap !< REAL(wp) :: lambda_r !< REAL(wp) :: mu_r !< REAL(wp) :: mu_r_2 !< REAL(wp) :: mu_r_5d2 !< REAL(wp) :: nr_0 !< REAL(wp) :: q_s !< REAL(wp) :: sat !< REAL(wp) :: t_l !< REAL(wp) :: temp !< REAL(wp) :: xr !< CALL cpu_log( log_point_s(58), 'evaporation', 'start' ) DO i = nxl, nxr DO j = nys, nyn DO k = nzb_s_inner(j,i)+1, nzt IF ( qr(k,j,i) > eps_sb ) THEN ! !-- Actual liquid water temperature: t_l = t_d_pt(k) * pt(k,j,i) ! !-- Saturation vapor pressure at t_l: e_s = 610.78_wp * EXP( 17.269_wp * ( t_l - 273.16_wp ) / & ( t_l - 35.86_wp ) & ) ! !-- Computation of saturation humidity: q_s = 0.622_wp * e_s / ( hyp(k) - 0.378_wp * e_s ) alpha = 0.622_wp * l_d_r * l_d_cp / ( t_l * t_l ) q_s = q_s * ( 1.0_wp + alpha * q(k,j,i) ) / & ( 1.0_wp + alpha * q_s ) ! !-- Supersaturation: sat = ( q(k,j,i) - qr(k,j,i) - qc(k,j,i) ) / q_s - 1.0_wp ! !-- Evaporation needs only to be calculated in subsaturated regions IF ( sat < 0.0_wp ) THEN ! !-- Actual temperature: temp = t_l + l_d_cp * ( qc(k,j,i) + qr(k,j,i) ) g_evap = 1.0_wp / ( ( l_v / ( r_v * temp ) - 1.0_wp ) * & l_v / ( thermal_conductivity_l * temp ) & + r_v * temp / ( diff_coeff_l * e_s ) & ) ! !-- Mean weight of rain drops xr = hyrho(k) * qr(k,j,i) / nr(k,j,i) ! !-- Weight averaged diameter of rain drops: dr = ( xr * dpirho_l )**( 1.0_wp / 3.0_wp ) ! !-- Compute ventilation factor and intercept parameter !-- (Seifert and Beheng, 2006; Seifert, 2008): IF ( ventilation_effect ) THEN ! !-- Shape parameter of gamma distribution (Milbrandt and Yau, !-- 2005; Stevens and Seifert, 2008): mu_r = 10.0_wp * ( 1.0_wp + TANH( 1.2E3_wp * & ( dr - 1.4E-3_wp ) ) ) ! !-- Slope parameter of gamma distribution (Seifert, 2008): lambda_r = ( ( mu_r + 3.0_wp ) * ( mu_r + 2.0_wp ) * & ( mu_r + 1.0_wp ) & )**( 1.0_wp / 3.0_wp ) / dr mu_r_2 = mu_r + 2.0_wp mu_r_5d2 = mu_r + 2.5_wp f_vent = a_vent * gamm( mu_r_2 ) * & lambda_r**( -mu_r_2 ) + b_vent * & schmidt_p_1d3 * SQRT( a_term / kin_vis_air ) *& gamm( mu_r_5d2 ) * lambda_r**( -mu_r_5d2 ) * & ( 1.0_wp - & 0.5_wp * ( b_term / a_term ) * & ( lambda_r / ( c_term + lambda_r ) & )**mu_r_5d2 - & 0.125_wp * ( b_term / a_term )**2 * & ( lambda_r / ( 2.0_wp * c_term + lambda_r ) & )**mu_r_5d2 - & 0.0625_wp * ( b_term / a_term )**3 * & ( lambda_r / ( 3.0_wp * c_term + lambda_r ) & )**mu_r_5d2 - & 0.0390625_wp * ( b_term / a_term )**4 * & ( lambda_r / ( 4.0_wp * c_term + lambda_r ) & )**mu_r_5d2 & ) nr_0 = nr(k,j,i) * lambda_r**( mu_r + 1.0_wp ) / & gamm( mu_r + 1.0_wp ) ELSE f_vent = 1.0_wp nr_0 = nr(k,j,i) * dr ENDIF ! !-- Evaporation rate of rain water content (Seifert and !-- Beheng, 2006): evap = 2.0_wp * pi * nr_0 * g_evap * f_vent * sat / & hyrho(k) evap = MAX( evap, -qr(k,j,i) / dt_micro ) evap_nr = MAX( c_evap * evap / xr * hyrho(k), & -nr(k,j,i) / dt_micro ) qr(k,j,i) = qr(k,j,i) + evap * dt_micro nr(k,j,i) = nr(k,j,i) + evap_nr * dt_micro ENDIF ENDIF ENDDO ENDDO ENDDO CALL cpu_log( log_point_s(58), 'evaporation', 'stop' ) END SUBROUTINE evaporation_rain !------------------------------------------------------------------------------! ! Description: ! ------------ !> Sedimentation of cloud droplets (Ackermann et al., 2009, MWR). !------------------------------------------------------------------------------! SUBROUTINE sedimentation_cloud USE arrays_3d, & ONLY: ddzu, dzu, pt, prr, q, qc USE cloud_parameters, & ONLY: hyrho, l_d_cp, pt_d_t USE control_parameters, & ONLY: call_microphysics_at_all_substeps, intermediate_timestep_count USE cpulog, & ONLY: cpu_log, log_point_s USE indices, & ONLY: nxl, nxr, nys, nyn, nzb, nzb_s_inner, nzt USE kinds USE statistics, & ONLY: weight_substep IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp), DIMENSION(nzb:nzt+1) :: sed_qc !< CALL cpu_log( log_point_s(59), 'sed_cloud', 'start' ) sed_qc(nzt+1) = 0.0_wp DO i = nxl, nxr DO j = nys, nyn DO k = nzt, nzb_s_inner(j,i)+1, -1 IF ( qc(k,j,i) > eps_sb ) THEN sed_qc(k) = sed_qc_const * nc_const**( -2.0_wp / 3.0_wp ) * & ( qc(k,j,i) * hyrho(k) )**( 5.0_wp / 3.0_wp ) ELSE sed_qc(k) = 0.0_wp ENDIF sed_qc(k) = MIN( sed_qc(k), hyrho(k) * dzu(k+1) * q(k,j,i) / & dt_micro + sed_qc(k+1) & ) q(k,j,i) = q(k,j,i) + ( sed_qc(k+1) - sed_qc(k) ) * & ddzu(k+1) / hyrho(k) * dt_micro qc(k,j,i) = qc(k,j,i) + ( sed_qc(k+1) - sed_qc(k) ) * & ddzu(k+1) / hyrho(k) * dt_micro pt(k,j,i) = pt(k,j,i) - ( sed_qc(k+1) - sed_qc(k) ) * & ddzu(k+1) / hyrho(k) * l_d_cp * & pt_d_t(k) * dt_micro ! !-- Compute the precipitation rate due to cloud (fog) droplets IF ( call_microphysics_at_all_substeps ) THEN prr(k,j,i) = prr(k,j,i) + sed_qc(k) / hyrho(k) & * weight_substep(intermediate_timestep_count) ELSE prr(k,j,i) = prr(k,j,i) + sed_qc(k) / hyrho(k) ENDIF ENDDO ENDDO ENDDO CALL cpu_log( log_point_s(59), 'sed_cloud', 'stop' ) END SUBROUTINE sedimentation_cloud !------------------------------------------------------------------------------! ! Description: ! ------------ !> Computation of sedimentation flux. Implementation according to Stevens !> and Seifert (2008). Code is based on UCLA-LES. !------------------------------------------------------------------------------! SUBROUTINE sedimentation_rain USE arrays_3d, & ONLY: ddzu, dzu, nr, pt, prr, q, qr USE cloud_parameters, & ONLY: hyrho, l_d_cp, pt_d_t USE control_parameters, & ONLY: call_microphysics_at_all_substeps, intermediate_timestep_count USE cpulog, & ONLY: cpu_log, log_point_s USE indices, & ONLY: nxl, nxr, nys, nyn, nzb, nzb_s_inner, nzt USE kinds USE statistics, & ONLY: weight_substep IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< INTEGER(iwp) :: k_run !< REAL(wp) :: c_run !< REAL(wp) :: d_max !< REAL(wp) :: d_mean !< REAL(wp) :: d_min !< REAL(wp) :: dr !< REAL(wp) :: flux !< REAL(wp) :: lambda_r !< REAL(wp) :: mu_r !< REAL(wp) :: z_run !< REAL(wp), DIMENSION(nzb:nzt+1) :: c_nr !< REAL(wp), DIMENSION(nzb:nzt+1) :: c_qr !< REAL(wp), DIMENSION(nzb:nzt+1) :: nr_slope !< REAL(wp), DIMENSION(nzb:nzt+1) :: qr_slope !< REAL(wp), DIMENSION(nzb:nzt+1) :: sed_nr !< REAL(wp), DIMENSION(nzb:nzt+1) :: sed_qr !< REAL(wp), DIMENSION(nzb:nzt+1) :: w_nr !< REAL(wp), DIMENSION(nzb:nzt+1) :: w_qr !< CALL cpu_log( log_point_s(60), 'sed_rain', 'start' ) ! !-- Compute velocities DO i = nxl, nxr DO j = nys, nyn DO k = nzb_s_inner(j,i)+1, nzt IF ( qr(k,j,i) > eps_sb ) THEN ! !-- Weight averaged diameter of rain drops: dr = ( hyrho(k) * qr(k,j,i) / & nr(k,j,i) * dpirho_l )**( 1.0_wp / 3.0_wp ) ! !-- Shape parameter of gamma distribution (Milbrandt and Yau, 2005; !-- Stevens and Seifert, 2008): mu_r = 10.0_wp * ( 1.0_wp + TANH( 1.2E3_wp * & ( dr - 1.4E-3_wp ) ) ) ! !-- Slope parameter of gamma distribution (Seifert, 2008): lambda_r = ( ( mu_r + 3.0_wp ) * ( mu_r + 2.0_wp ) * & ( mu_r + 1.0_wp ) )**( 1.0_wp / 3.0_wp ) / dr w_nr(k) = MAX( 0.1_wp, MIN( 20.0_wp, & a_term - b_term * ( 1.0_wp + & c_term / & lambda_r )**( -1.0_wp * & ( mu_r + 1.0_wp ) ) & ) & ) w_qr(k) = MAX( 0.1_wp, MIN( 20.0_wp, & a_term - b_term * ( 1.0_wp + & c_term / & lambda_r )**( -1.0_wp * & ( mu_r + 4.0_wp ) ) & ) & ) ELSE w_nr(k) = 0.0_wp w_qr(k) = 0.0_wp ENDIF ENDDO ! !-- Adjust boundary values w_nr(nzb_s_inner(j,i)) = w_nr(nzb_s_inner(j,i)+1) w_qr(nzb_s_inner(j,i)) = w_qr(nzb_s_inner(j,i)+1) w_nr(nzt+1) = 0.0_wp w_qr(nzt+1) = 0.0_wp ! !-- Compute Courant number DO k = nzb_s_inner(j,i)+1, nzt c_nr(k) = 0.25_wp * ( w_nr(k-1) + & 2.0_wp * w_nr(k) + w_nr(k+1) ) * & dt_micro * ddzu(k) c_qr(k) = 0.25_wp * ( w_qr(k-1) + & 2.0_wp * w_qr(k) + w_qr(k+1) ) * & dt_micro * ddzu(k) ENDDO ! !-- Limit slopes with monotonized centered (MC) limiter (van Leer, 1977): IF ( limiter_sedimentation ) THEN DO k = nzb_s_inner(j,i)+1, nzt d_mean = 0.5_wp * ( qr(k+1,j,i) - qr(k-1,j,i) ) d_min = qr(k,j,i) - MIN( qr(k+1,j,i), qr(k,j,i), qr(k-1,j,i) ) d_max = MAX( qr(k+1,j,i), qr(k,j,i), qr(k-1,j,i) ) - qr(k,j,i) qr_slope(k) = SIGN(1.0_wp, d_mean) * MIN ( 2.0_wp * d_min, & 2.0_wp * d_max, & ABS( d_mean ) ) d_mean = 0.5_wp * ( nr(k+1,j,i) - nr(k-1,j,i) ) d_min = nr(k,j,i) - MIN( nr(k+1,j,i), nr(k,j,i), nr(k-1,j,i) ) d_max = MAX( nr(k+1,j,i), nr(k,j,i), nr(k-1,j,i) ) - nr(k,j,i) nr_slope(k) = SIGN(1.0_wp, d_mean) * MIN ( 2.0_wp * d_min, & 2.0_wp * d_max, & ABS( d_mean ) ) ENDDO ELSE nr_slope = 0.0_wp qr_slope = 0.0_wp ENDIF sed_nr(nzt+1) = 0.0_wp sed_qr(nzt+1) = 0.0_wp ! !-- Compute sedimentation flux DO k = nzt, nzb_s_inner(j,i)+1, -1 ! !-- Sum up all rain drop number densities which contribute to the flux !-- through k-1/2 flux = 0.0_wp z_run = 0.0_wp ! height above z(k) k_run = k c_run = MIN( 1.0_wp, c_nr(k) ) DO WHILE ( c_run > 0.0_wp .AND. k_run <= nzt ) flux = flux + hyrho(k_run) * & ( nr(k_run,j,i) + nr_slope(k_run) * & ( 1.0_wp - c_run ) * 0.5_wp ) * c_run * dzu(k_run) z_run = z_run + dzu(k_run) k_run = k_run + 1 c_run = MIN( 1.0_wp, c_nr(k_run) - z_run * ddzu(k_run) ) ENDDO ! !-- It is not allowed to sediment more rain drop number density than !-- available flux = MIN( flux, & hyrho(k) * dzu(k+1) * nr(k,j,i) + sed_nr(k+1) * & dt_micro & ) sed_nr(k) = flux / dt_micro nr(k,j,i) = nr(k,j,i) + ( sed_nr(k+1) - sed_nr(k) ) * & ddzu(k+1) / hyrho(k) * dt_micro ! !-- Sum up all rain water content which contributes to the flux !-- through k-1/2 flux = 0.0_wp z_run = 0.0_wp ! height above z(k) k_run = k c_run = MIN( 1.0_wp, c_qr(k) ) DO WHILE ( c_run > 0.0_wp .AND. k_run <= nzt ) flux = flux + hyrho(k_run) * ( qr(k_run,j,i) + & qr_slope(k_run) * ( 1.0_wp - c_run ) * & 0.5_wp ) * c_run * dzu(k_run) z_run = z_run + dzu(k_run) k_run = k_run + 1 c_run = MIN( 1.0_wp, c_qr(k_run) - z_run * ddzu(k_run) ) ENDDO ! !-- It is not allowed to sediment more rain water content than !-- available flux = MIN( flux, & hyrho(k) * dzu(k) * qr(k,j,i) + sed_qr(k+1) * & dt_micro & ) sed_qr(k) = flux / dt_micro qr(k,j,i) = qr(k,j,i) + ( sed_qr(k+1) - sed_qr(k) ) * & ddzu(k+1) / hyrho(k) * dt_micro q(k,j,i) = q(k,j,i) + ( sed_qr(k+1) - sed_qr(k) ) * & ddzu(k+1) / hyrho(k) * dt_micro pt(k,j,i) = pt(k,j,i) - ( sed_qr(k+1) - sed_qr(k) ) * & ddzu(k+1) / hyrho(k) * l_d_cp * & pt_d_t(k) * dt_micro ! !-- Compute the rain rate IF ( call_microphysics_at_all_substeps ) THEN prr(k,j,i) = prr(k,j,i) + sed_qr(k) / hyrho(k) & * weight_substep(intermediate_timestep_count) ELSE prr(k,j,i) = prr(k,j,i) + sed_qr(k) / hyrho(k) ENDIF ENDDO ENDDO ENDDO CALL cpu_log( log_point_s(60), 'sed_rain', 'stop' ) END SUBROUTINE sedimentation_rain !------------------------------------------------------------------------------! ! Description: ! ------------ !> Computation of the precipitation amount due to gravitational settling of !> rain and cloud (fog) droplets !------------------------------------------------------------------------------! SUBROUTINE calc_precipitation_amount USE arrays_3d, & ONLY: precipitation_amount, prr USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: call_microphysics_at_all_substeps, dt_do2d_xy, dt_3d, & intermediate_timestep_count, intermediate_timestep_count_max,& precipitation_amount_interval, time_do2d_xy USE indices, & ONLY: nxl, nxr, nys, nyn, nzb_s_inner USE kinds IMPLICIT NONE INTEGER(iwp) :: i !: INTEGER(iwp) :: j !: IF ( ( dt_do2d_xy - time_do2d_xy ) < precipitation_amount_interval .AND.& ( .NOT. call_microphysics_at_all_substeps .OR. & intermediate_timestep_count == intermediate_timestep_count_max ) ) & THEN DO i = nxl, nxr DO j = nys, nyn precipitation_amount(j,i) = precipitation_amount(j,i) + & prr(nzb_s_inner(j,i)+1,j,i) * & hyrho(nzb_s_inner(j,i)+1) * dt_3d ENDDO ENDDO ENDIF END SUBROUTINE calc_precipitation_amount !------------------------------------------------------------------------------! ! Description: ! ------------ !> Control of microphysics for grid points i,j !------------------------------------------------------------------------------! SUBROUTINE microphysics_control_ij( i, j ) USE arrays_3d, & ONLY: hyp, nr, pt, pt_init, prr, q, qc, qr, zu USE cloud_parameters, & ONLY: cp, hyrho, pt_d_t, r_d, t_d_pt USE control_parameters, & ONLY: call_microphysics_at_all_substeps, dt_3d, g, & intermediate_timestep_count, large_scale_forcing, & lsf_surf, microphysics_seifert, microphysics_kessler, & pt_surface, rho_surface, surface_pressure USE indices, & ONLY: nzb, nzt USE kinds USE statistics, & ONLY: weight_pres IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: t_surface !< IF ( large_scale_forcing .AND. lsf_surf ) THEN ! !-- Calculate: !-- pt / t : ratio of potential and actual temperature (pt_d_t) !-- t / pt : ratio of actual and potential temperature (t_d_pt) !-- p_0(z) : vertical profile of the hydrostatic pressure (hyp) t_surface = pt_surface * ( surface_pressure / 1000.0_wp )**0.286_wp DO k = nzb, nzt+1 hyp(k) = surface_pressure * 100.0_wp * & ( ( t_surface - g / cp * zu(k) ) / t_surface )**(1.0_wp / 0.286_wp) pt_d_t(k) = ( 100000.0_wp / hyp(k) )**0.286_wp t_d_pt(k) = 1.0_wp / pt_d_t(k) hyrho(k) = hyp(k) / ( r_d * t_d_pt(k) * pt_init(k) ) ENDDO ! !-- Compute reference density rho_surface = surface_pressure * 100.0_wp / ( r_d * t_surface ) ENDIF ! !-- Compute length of time step IF ( call_microphysics_at_all_substeps ) THEN dt_micro = dt_3d * weight_pres(intermediate_timestep_count) ELSE dt_micro = dt_3d ENDIF ! !-- Use 1d arrays q_1d(:) = q(:,j,i) pt_1d(:) = pt(:,j,i) qc_1d(:) = qc(:,j,i) nc_1d(:) = nc_const IF ( microphysics_seifert ) THEN qr_1d(:) = qr(:,j,i) nr_1d(:) = nr(:,j,i) ENDIF ! !-- Reset precipitation rate IF ( intermediate_timestep_count == 1 ) prr(:,j,i) = 0.0_wp ! !-- Compute cloud physics IF( microphysics_kessler ) THEN CALL autoconversion_kessler( i,j ) IF ( cloud_water_sedimentation ) CALL sedimentation_cloud( i,j ) ELSEIF ( microphysics_seifert ) THEN CALL adjust_cloud( i,j ) CALL autoconversion( i,j ) CALL accretion( i,j ) CALL selfcollection_breakup( i,j ) CALL evaporation_rain( i,j ) CALL sedimentation_rain( i,j ) IF ( cloud_water_sedimentation ) CALL sedimentation_cloud( i,j ) ENDIF CALL calc_precipitation_amount( i,j ) ! !-- Store results on the 3d arrays q(:,j,i) = q_1d(:) pt(:,j,i) = pt_1d(:) IF ( microphysics_seifert ) THEN qr(:,j,i) = qr_1d(:) nr(:,j,i) = nr_1d(:) ENDIF END SUBROUTINE microphysics_control_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Adjust number of raindrops to avoid nonlinear effects in !> sedimentation and evaporation of rain drops due to too small or !> too big weights of rain drops (Stevens and Seifert, 2008). !> The same procedure is applied to cloud droplets if they are determined !> prognostically. Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE adjust_cloud_ij( i, j ) USE cloud_parameters, & ONLY: hyrho USE indices, & ONLY: nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< DO k = nzb_s_inner(j,i)+1, nzt IF ( qr_1d(k) <= eps_sb ) THEN qr_1d(k) = 0.0_wp nr_1d(k) = 0.0_wp ELSE ! !-- Adjust number of raindrops to avoid nonlinear effects in !-- sedimentation and evaporation of rain drops due to too small or !-- too big weights of rain drops (Stevens and Seifert, 2008). IF ( nr_1d(k) * xrmin > qr_1d(k) * hyrho(k) ) THEN nr_1d(k) = qr_1d(k) * hyrho(k) / xrmin ELSEIF ( nr_1d(k) * xrmax < qr_1d(k) * hyrho(k) ) THEN nr_1d(k) = qr_1d(k) * hyrho(k) / xrmax ENDIF ENDIF ENDDO END SUBROUTINE adjust_cloud_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Autoconversion rate (Seifert and Beheng, 2006). Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE autoconversion_ij( i, j ) USE arrays_3d, & ONLY: diss, dzu USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: rho_surface USE grid_variables, & ONLY: dx, dy USE indices, & ONLY: nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: alpha_cc !< REAL(wp) :: autocon !< REAL(wp) :: dissipation !< REAL(wp) :: k_au !< REAL(wp) :: l_mix !< REAL(wp) :: nu_c !< REAL(wp) :: phi_au !< REAL(wp) :: r_cc !< REAL(wp) :: rc !< REAL(wp) :: re_lambda !< REAL(wp) :: sigma_cc !< REAL(wp) :: tau_cloud !< REAL(wp) :: xc !< DO k = nzb_s_inner(j,i)+1, nzt IF ( qc_1d(k) > eps_sb ) THEN k_au = k_cc / ( 20.0_wp * x0 ) ! !-- Intern time scale of coagulation (Seifert and Beheng, 2006): !-- (1.0_wp - qc(k,j,i) / ( qc(k,j,i) + qr_1d(k) )) tau_cloud = 1.0_wp - qc_1d(k) / ( qr_1d(k) + qc_1d(k) ) ! !-- Universal function for autoconversion process !-- (Seifert and Beheng, 2006): phi_au = 600.0_wp * tau_cloud**0.68_wp * ( 1.0_wp - tau_cloud**0.68_wp )**3 ! !-- Shape parameter of gamma distribution (Geoffroy et al., 2010): !-- (Use constant nu_c = 1.0_wp instead?) nu_c = 1.0_wp !MAX( 0.0_wp, 1580.0_wp * hyrho(k) * qc_1d(k) - 0.28_wp ) ! !-- Mean weight of cloud droplets: xc = hyrho(k) * qc_1d(k) / nc_1d(k) ! !-- Parameterized turbulence effects on autoconversion (Seifert, !-- Nuijens and Stevens, 2010) IF ( collision_turbulence ) THEN ! !-- Weight averaged radius of cloud droplets: rc = 0.5_wp * ( xc * dpirho_l )**( 1.0_wp / 3.0_wp ) alpha_cc = ( a_1 + a_2 * nu_c ) / ( 1.0_wp + a_3 * nu_c ) r_cc = ( b_1 + b_2 * nu_c ) / ( 1.0_wp + b_3 * nu_c ) sigma_cc = ( c_1 + c_2 * nu_c ) / ( 1.0_wp + c_3 * nu_c ) ! !-- Mixing length (neglecting distance to ground and stratification) l_mix = ( dx * dy * dzu(k) )**( 1.0_wp / 3.0_wp ) ! !-- Limit dissipation rate according to Seifert, Nuijens and !-- Stevens (2010) dissipation = MIN( 0.06_wp, diss(k,j,i) ) ! !-- Compute Taylor-microscale Reynolds number: re_lambda = 6.0_wp / 11.0_wp * & ( l_mix / c_const )**( 2.0_wp / 3.0_wp ) * & SQRT( 15.0_wp / kin_vis_air ) * & dissipation**( 1.0_wp / 6.0_wp ) ! !-- The factor of 1.0E4 is needed to convert the dissipation rate !-- from m2 s-3 to cm2 s-3. k_au = k_au * ( 1.0_wp + & dissipation * 1.0E4_wp * & ( re_lambda * 1.0E-3_wp )**0.25_wp * & ( alpha_cc * EXP( -1.0_wp * ( ( rc - r_cc ) / & sigma_cc )**2 & ) + beta_cc & ) & ) ENDIF ! !-- Autoconversion rate (Seifert and Beheng, 2006): autocon = k_au * ( nu_c + 2.0_wp ) * ( nu_c + 4.0_wp ) / & ( nu_c + 1.0_wp )**2 * qc_1d(k)**2 * xc**2 * & ( 1.0_wp + phi_au / ( 1.0_wp - tau_cloud )**2 ) * & rho_surface autocon = MIN( autocon, qc_1d(k) / dt_micro ) qr_1d(k) = qr_1d(k) + autocon * dt_micro qc_1d(k) = qc_1d(k) - autocon * dt_micro nr_1d(k) = nr_1d(k) + autocon / x0 * hyrho(k) * dt_micro ENDIF ENDDO END SUBROUTINE autoconversion_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Autoconversion process (Kessler, 1969). !------------------------------------------------------------------------------! SUBROUTINE autoconversion_kessler_ij( i, j ) USE arrays_3d, & ONLY: dzw, prr USE cloud_parameters, & ONLY: l_d_cp, pt_d_t USE indices, & ONLY: nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: dqdt_precip !< DO k = nzb_s_inner(j,i)+1, nzt IF ( qc_1d(k) > ql_crit ) THEN dqdt_precip = prec_time_const * ( qc_1d(k) - ql_crit ) ELSE dqdt_precip = 0.0_wp ENDIF qc_1d(k) = qc_1d(k) - dqdt_precip * dt_micro q_1d(k) = q_1d(k) - dqdt_precip * dt_micro pt_1d(k) = pt_1d(k) + dqdt_precip * dt_micro * l_d_cp * pt_d_t(k) ! !-- Compute the rain rate (stored on surface grid point) prr(nzb_s_inner(j,i),j,i) = prr(nzb_s_inner(j,i),j,i) + & dqdt_precip * dzw(k) ENDDO END SUBROUTINE autoconversion_kessler_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Accretion rate (Seifert and Beheng, 2006). Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE accretion_ij( i, j ) USE arrays_3d, & ONLY: diss USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: rho_surface USE indices, & ONLY: nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: accr !< REAL(wp) :: k_cr !< REAL(wp) :: phi_ac !< REAL(wp) :: tau_cloud !< DO k = nzb_s_inner(j,i)+1, nzt IF ( ( qc_1d(k) > eps_sb ) .AND. ( qr_1d(k) > eps_sb ) ) THEN ! !-- Intern time scale of coagulation (Seifert and Beheng, 2006): tau_cloud = 1.0_wp - qc_1d(k) / ( qc_1d(k) + qr_1d(k) ) ! !-- Universal function for accretion process !-- (Seifert and Beheng, 2001): phi_ac = ( tau_cloud / ( tau_cloud + 5.0E-5_wp ) )**4 ! !-- Parameterized turbulence effects on autoconversion (Seifert, !-- Nuijens and Stevens, 2010). The factor of 1.0E4 is needed to !-- convert the dissipation rate (diss) from m2 s-3 to cm2 s-3. IF ( collision_turbulence ) THEN k_cr = k_cr0 * ( 1.0_wp + 0.05_wp * & MIN( 600.0_wp, & diss(k,j,i) * 1.0E4_wp )**0.25_wp & ) ELSE k_cr = k_cr0 ENDIF ! !-- Accretion rate (Seifert and Beheng, 2006): accr = k_cr * qc_1d(k) * qr_1d(k) * phi_ac * SQRT( rho_surface * hyrho(k) ) accr = MIN( accr, qc_1d(k) / dt_micro ) qr_1d(k) = qr_1d(k) + accr * dt_micro qc_1d(k) = qc_1d(k) - accr * dt_micro ENDIF ENDDO END SUBROUTINE accretion_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Collisional breakup rate (Seifert, 2008). Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE selfcollection_breakup_ij( i, j ) USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: rho_surface USE indices, & ONLY: nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: breakup !< REAL(wp) :: dr !< REAL(wp) :: phi_br !< REAL(wp) :: selfcoll !< DO k = nzb_s_inner(j,i)+1, nzt IF ( qr_1d(k) > eps_sb ) THEN ! !-- Selfcollection rate (Seifert and Beheng, 2001): selfcoll = k_rr * nr_1d(k) * qr_1d(k) * SQRT( hyrho(k) * rho_surface ) ! !-- Weight averaged diameter of rain drops: dr = ( hyrho(k) * qr_1d(k) / nr_1d(k) * dpirho_l )**( 1.0_wp / 3.0_wp ) ! !-- Collisional breakup rate (Seifert, 2008): IF ( dr >= 0.3E-3_wp ) THEN phi_br = k_br * ( dr - 1.1E-3_wp ) breakup = selfcoll * ( phi_br + 1.0_wp ) ELSE breakup = 0.0_wp ENDIF selfcoll = MAX( breakup - selfcoll, -nr_1d(k) / dt_micro ) nr_1d(k) = nr_1d(k) + selfcoll * dt_micro ENDIF ENDDO END SUBROUTINE selfcollection_breakup_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Evaporation of precipitable water. Condensation is neglected for !> precipitable water. Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE evaporation_rain_ij( i, j ) USE arrays_3d, & ONLY: hyp USE cloud_parameters, & ONLY: hyrho, l_d_cp, l_d_r, l_v, r_v, t_d_pt USE constants, & ONLY: pi USE indices, & ONLY: nzb_s_inner, nzt USE kinds IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp) :: alpha !< REAL(wp) :: dr !< REAL(wp) :: e_s !< REAL(wp) :: evap !< REAL(wp) :: evap_nr !< REAL(wp) :: f_vent !< REAL(wp) :: g_evap !< REAL(wp) :: lambda_r !< REAL(wp) :: mu_r !< REAL(wp) :: mu_r_2 !< REAL(wp) :: mu_r_5d2 !< REAL(wp) :: nr_0 !< REAL(wp) :: q_s !< REAL(wp) :: sat !< REAL(wp) :: t_l !< REAL(wp) :: temp !< REAL(wp) :: xr !< DO k = nzb_s_inner(j,i)+1, nzt IF ( qr_1d(k) > eps_sb ) THEN ! !-- Actual liquid water temperature: t_l = t_d_pt(k) * pt_1d(k) ! !-- Saturation vapor pressure at t_l: e_s = 610.78_wp * EXP( 17.269_wp * ( t_l - 273.16_wp ) / & ( t_l - 35.86_wp ) & ) ! !-- Computation of saturation humidity: q_s = 0.622_wp * e_s / ( hyp(k) - 0.378_wp * e_s ) alpha = 0.622_wp * l_d_r * l_d_cp / ( t_l * t_l ) q_s = q_s * ( 1.0_wp + alpha * q_1d(k) ) / ( 1.0_wp + alpha * q_s ) ! !-- Supersaturation: sat = ( q_1d(k) - qr_1d(k) - qc_1d(k) ) / q_s - 1.0_wp ! !-- Evaporation needs only to be calculated in subsaturated regions IF ( sat < 0.0_wp ) THEN ! !-- Actual temperature: temp = t_l + l_d_cp * ( qc_1d(k) + qr_1d(k) ) g_evap = 1.0_wp / ( ( l_v / ( r_v * temp ) - 1.0_wp ) * l_v / & ( thermal_conductivity_l * temp ) + & r_v * temp / ( diff_coeff_l * e_s ) & ) ! !-- Mean weight of rain drops xr = hyrho(k) * qr_1d(k) / nr_1d(k) ! !-- Weight averaged diameter of rain drops: dr = ( xr * dpirho_l )**( 1.0_wp / 3.0_wp ) ! !-- Compute ventilation factor and intercept parameter !-- (Seifert and Beheng, 2006; Seifert, 2008): IF ( ventilation_effect ) THEN ! !-- Shape parameter of gamma distribution (Milbrandt and Yau, 2005; !-- Stevens and Seifert, 2008): mu_r = 10.0_wp * ( 1.0_wp + TANH( 1.2E3_wp * ( dr - 1.4E-3_wp ) ) ) ! !-- Slope parameter of gamma distribution (Seifert, 2008): lambda_r = ( ( mu_r + 3.0_wp ) * ( mu_r + 2.0_wp ) * & ( mu_r + 1.0_wp ) & )**( 1.0_wp / 3.0_wp ) / dr mu_r_2 = mu_r + 2.0_wp mu_r_5d2 = mu_r + 2.5_wp f_vent = a_vent * gamm( mu_r_2 ) * lambda_r**( -mu_r_2 ) + & b_vent * schmidt_p_1d3 * & SQRT( a_term / kin_vis_air ) * gamm( mu_r_5d2 ) * & lambda_r**( -mu_r_5d2 ) * & ( 1.0_wp - & 0.5_wp * ( b_term / a_term ) * & ( lambda_r / ( c_term + lambda_r ) & )**mu_r_5d2 - & 0.125_wp * ( b_term / a_term )**2 * & ( lambda_r / ( 2.0_wp * c_term + lambda_r ) & )**mu_r_5d2 - & 0.0625_wp * ( b_term / a_term )**3 * & ( lambda_r / ( 3.0_wp * c_term + lambda_r ) & )**mu_r_5d2 - & 0.0390625_wp * ( b_term / a_term )**4 * & ( lambda_r / ( 4.0_wp * c_term + lambda_r ) & )**mu_r_5d2 & ) nr_0 = nr_1d(k) * lambda_r**( mu_r + 1.0_wp ) / & gamm( mu_r + 1.0_wp ) ELSE f_vent = 1.0_wp nr_0 = nr_1d(k) * dr ENDIF ! !-- Evaporation rate of rain water content (Seifert and Beheng, 2006): evap = 2.0_wp * pi * nr_0 * g_evap * f_vent * sat / hyrho(k) evap = MAX( evap, -qr_1d(k) / dt_micro ) evap_nr = MAX( c_evap * evap / xr * hyrho(k), & -nr_1d(k) / dt_micro ) qr_1d(k) = qr_1d(k) + evap * dt_micro nr_1d(k) = nr_1d(k) + evap_nr * dt_micro ENDIF ENDIF ENDDO END SUBROUTINE evaporation_rain_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Sedimentation of cloud droplets (Ackermann et al., 2009, MWR). !> Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE sedimentation_cloud_ij( i, j ) USE arrays_3d, & ONLY: ddzu, dzu, prr USE cloud_parameters, & ONLY: hyrho, l_d_cp, pt_d_t USE control_parameters, & ONLY: call_microphysics_at_all_substeps, intermediate_timestep_count USE indices, & ONLY: nzb, nzb_s_inner, nzt USE kinds USE statistics, & ONLY: weight_substep IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< REAL(wp), DIMENSION(nzb:nzt+1) :: sed_qc !< sed_qc(nzt+1) = 0.0_wp DO k = nzt, nzb_s_inner(j,i)+1, -1 IF ( qc_1d(k) > eps_sb ) THEN sed_qc(k) = sed_qc_const * nc_1d(k)**( -2.0_wp / 3.0_wp ) * & ( qc_1d(k) * hyrho(k) )**( 5.0_wp / 3.0_wp ) ELSE sed_qc(k) = 0.0_wp ENDIF sed_qc(k) = MIN( sed_qc(k), hyrho(k) * dzu(k+1) * q_1d(k) / & dt_micro + sed_qc(k+1) & ) q_1d(k) = q_1d(k) + ( sed_qc(k+1) - sed_qc(k) ) * ddzu(k+1) / & hyrho(k) * dt_micro qc_1d(k) = qc_1d(k) + ( sed_qc(k+1) - sed_qc(k) ) * ddzu(k+1) / & hyrho(k) * dt_micro pt_1d(k) = pt_1d(k) - ( sed_qc(k+1) - sed_qc(k) ) * ddzu(k+1) / & hyrho(k) * l_d_cp * pt_d_t(k) * dt_micro ! !-- Compute the precipitation rate of cloud (fog) droplets IF ( call_microphysics_at_all_substeps ) THEN prr(k,j,i) = prr(k,j,i) + sed_qc(k) / hyrho(k) * & weight_substep(intermediate_timestep_count) ELSE prr(k,j,i) = prr(k,j,i) + sed_qc(k) / hyrho(k) ENDIF ENDDO END SUBROUTINE sedimentation_cloud_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> Computation of sedimentation flux. Implementation according to Stevens !> and Seifert (2008). Code is based on UCLA-LES. Call for grid point i,j !------------------------------------------------------------------------------! SUBROUTINE sedimentation_rain_ij( i, j ) USE arrays_3d, & ONLY: ddzu, dzu, prr USE cloud_parameters, & ONLY: hyrho, l_d_cp, pt_d_t USE control_parameters, & ONLY: call_microphysics_at_all_substeps, intermediate_timestep_count USE indices, & ONLY: nzb, nzb_s_inner, nzt USE kinds USE statistics, & ONLY: weight_substep IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< INTEGER(iwp) :: k_run !< REAL(wp) :: c_run !< REAL(wp) :: d_max !< REAL(wp) :: d_mean !< REAL(wp) :: d_min !< REAL(wp) :: dr !< REAL(wp) :: flux !< REAL(wp) :: lambda_r !< REAL(wp) :: mu_r !< REAL(wp) :: z_run !< REAL(wp), DIMENSION(nzb:nzt+1) :: c_nr !< REAL(wp), DIMENSION(nzb:nzt+1) :: c_qr !< REAL(wp), DIMENSION(nzb:nzt+1) :: nr_slope !< REAL(wp), DIMENSION(nzb:nzt+1) :: qr_slope !< REAL(wp), DIMENSION(nzb:nzt+1) :: sed_nr !< REAL(wp), DIMENSION(nzb:nzt+1) :: sed_qr !< REAL(wp), DIMENSION(nzb:nzt+1) :: w_nr !< REAL(wp), DIMENSION(nzb:nzt+1) :: w_qr !< ! !-- Compute velocities DO k = nzb_s_inner(j,i)+1, nzt IF ( qr_1d(k) > eps_sb ) THEN ! !-- Weight averaged diameter of rain drops: dr = ( hyrho(k) * qr_1d(k) / nr_1d(k) * dpirho_l )**( 1.0_wp / 3.0_wp ) ! !-- Shape parameter of gamma distribution (Milbrandt and Yau, 2005; !-- Stevens and Seifert, 2008): mu_r = 10.0_wp * ( 1.0_wp + TANH( 1.2E3_wp * ( dr - 1.4E-3_wp ) ) ) ! !-- Slope parameter of gamma distribution (Seifert, 2008): lambda_r = ( ( mu_r + 3.0_wp ) * ( mu_r + 2.0_wp ) * & ( mu_r + 1.0_wp ) )**( 1.0_wp / 3.0_wp ) / dr w_nr(k) = MAX( 0.1_wp, MIN( 20.0_wp, & a_term - b_term * ( 1.0_wp + & c_term / lambda_r )**( -1.0_wp * & ( mu_r + 1.0_wp ) ) & ) & ) w_qr(k) = MAX( 0.1_wp, MIN( 20.0_wp, & a_term - b_term * ( 1.0_wp + & c_term / lambda_r )**( -1.0_wp * & ( mu_r + 4.0_wp ) ) & ) & ) ELSE w_nr(k) = 0.0_wp w_qr(k) = 0.0_wp ENDIF ENDDO ! !-- Adjust boundary values w_nr(nzb_s_inner(j,i)) = w_nr(nzb_s_inner(j,i)+1) w_qr(nzb_s_inner(j,i)) = w_qr(nzb_s_inner(j,i)+1) w_nr(nzt+1) = 0.0_wp w_qr(nzt+1) = 0.0_wp ! !-- Compute Courant number DO k = nzb_s_inner(j,i)+1, nzt c_nr(k) = 0.25_wp * ( w_nr(k-1) + 2.0_wp * w_nr(k) + w_nr(k+1) ) * & dt_micro * ddzu(k) c_qr(k) = 0.25_wp * ( w_qr(k-1) + 2.0_wp * w_qr(k) + w_qr(k+1) ) * & dt_micro * ddzu(k) ENDDO ! !-- Limit slopes with monotonized centered (MC) limiter (van Leer, 1977): IF ( limiter_sedimentation ) THEN DO k = nzb_s_inner(j,i)+1, nzt d_mean = 0.5_wp * ( qr_1d(k+1) - qr_1d(k-1) ) d_min = qr_1d(k) - MIN( qr_1d(k+1), qr_1d(k), qr_1d(k-1) ) d_max = MAX( qr_1d(k+1), qr_1d(k), qr_1d(k-1) ) - qr_1d(k) qr_slope(k) = SIGN(1.0_wp, d_mean) * MIN ( 2.0_wp * d_min, & 2.0_wp * d_max, & ABS( d_mean ) ) d_mean = 0.5_wp * ( nr_1d(k+1) - nr_1d(k-1) ) d_min = nr_1d(k) - MIN( nr_1d(k+1), nr_1d(k), nr_1d(k-1) ) d_max = MAX( nr_1d(k+1), nr_1d(k), nr_1d(k-1) ) - nr_1d(k) nr_slope(k) = SIGN(1.0_wp, d_mean) * MIN ( 2.0_wp * d_min, & 2.0_wp * d_max, & ABS( d_mean ) ) ENDDO ELSE nr_slope = 0.0_wp qr_slope = 0.0_wp ENDIF sed_nr(nzt+1) = 0.0_wp sed_qr(nzt+1) = 0.0_wp ! !-- Compute sedimentation flux DO k = nzt, nzb_s_inner(j,i)+1, -1 ! !-- Sum up all rain drop number densities which contribute to the flux !-- through k-1/2 flux = 0.0_wp z_run = 0.0_wp ! height above z(k) k_run = k c_run = MIN( 1.0_wp, c_nr(k) ) DO WHILE ( c_run > 0.0_wp .AND. k_run <= nzt ) flux = flux + hyrho(k_run) * & ( nr_1d(k_run) + nr_slope(k_run) * ( 1.0_wp - c_run ) * & 0.5_wp ) * c_run * dzu(k_run) z_run = z_run + dzu(k_run) k_run = k_run + 1 c_run = MIN( 1.0_wp, c_nr(k_run) - z_run * ddzu(k_run) ) ENDDO ! !-- It is not allowed to sediment more rain drop number density than !-- available flux = MIN( flux, & hyrho(k) * dzu(k+1) * nr_1d(k) + sed_nr(k+1) * dt_micro ) sed_nr(k) = flux / dt_micro nr_1d(k) = nr_1d(k) + ( sed_nr(k+1) - sed_nr(k) ) * ddzu(k+1) / & hyrho(k) * dt_micro ! !-- Sum up all rain water content which contributes to the flux !-- through k-1/2 flux = 0.0_wp z_run = 0.0_wp ! height above z(k) k_run = k c_run = MIN( 1.0_wp, c_qr(k) ) DO WHILE ( c_run > 0.0_wp .AND. k_run <= nzt ) flux = flux + hyrho(k_run) * & ( qr_1d(k_run) + qr_slope(k_run) * ( 1.0_wp - c_run ) * & 0.5_wp ) * c_run * dzu(k_run) z_run = z_run + dzu(k_run) k_run = k_run + 1 c_run = MIN( 1.0_wp, c_qr(k_run) - z_run * ddzu(k_run) ) ENDDO ! !-- It is not allowed to sediment more rain water content than available flux = MIN( flux, & hyrho(k) * dzu(k) * qr_1d(k) + sed_qr(k+1) * dt_micro ) sed_qr(k) = flux / dt_micro qr_1d(k) = qr_1d(k) + ( sed_qr(k+1) - sed_qr(k) ) * ddzu(k+1) / & hyrho(k) * dt_micro q_1d(k) = q_1d(k) + ( sed_qr(k+1) - sed_qr(k) ) * ddzu(k+1) / & hyrho(k) * dt_micro pt_1d(k) = pt_1d(k) - ( sed_qr(k+1) - sed_qr(k) ) * ddzu(k+1) / & hyrho(k) * l_d_cp * pt_d_t(k) * dt_micro ! !-- Compute the rain rate IF ( call_microphysics_at_all_substeps ) THEN prr(k,j,i) = prr(k,j,i) + sed_qr(k) / hyrho(k) & * weight_substep(intermediate_timestep_count) ELSE prr(k,j,i) = prr(k,j,i) + sed_qr(k) / hyrho(k) ENDIF ENDDO END SUBROUTINE sedimentation_rain_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> This subroutine computes the precipitation amount due to gravitational !> settling of rain and cloud (fog) droplets !------------------------------------------------------------------------------! SUBROUTINE calc_precipitation_amount_ij( i, j ) USE arrays_3d, & ONLY: precipitation_amount, prr USE cloud_parameters, & ONLY: hyrho USE control_parameters, & ONLY: call_microphysics_at_all_substeps, dt_do2d_xy, dt_3d, & intermediate_timestep_count, intermediate_timestep_count_max,& precipitation_amount_interval, time_do2d_xy USE indices, & ONLY: nzb_s_inner USE kinds IMPLICIT NONE INTEGER(iwp) :: i !: INTEGER(iwp) :: j !: IF ( ( dt_do2d_xy - time_do2d_xy ) < precipitation_amount_interval .AND.& ( .NOT. call_microphysics_at_all_substeps .OR. & intermediate_timestep_count == intermediate_timestep_count_max ) ) & THEN precipitation_amount(j,i) = precipitation_amount(j,i) + & prr(nzb_s_inner(j,i)+1,j,i) * & hyrho(nzb_s_inner(j,i)+1) * dt_3d ENDIF END SUBROUTINE calc_precipitation_amount_ij !------------------------------------------------------------------------------! ! Description: ! ------------ !> This function computes the gamma function (Press et al., 1992). !> The gamma function is needed for the calculation of the evaporation !> of rain drops. !------------------------------------------------------------------------------! FUNCTION gamm( xx ) USE kinds IMPLICIT NONE INTEGER(iwp) :: j !< REAL(wp) :: gamm !< REAL(wp) :: ser !< REAL(wp) :: tmp !< REAL(wp) :: x_gamm !< REAL(wp) :: xx !< REAL(wp) :: y_gamm !< REAL(wp), PARAMETER :: stp = 2.5066282746310005_wp !< REAL(wp), PARAMETER :: cof(6) = (/ 76.18009172947146_wp, & -86.50532032941677_wp, & 24.01409824083091_wp, & -1.231739572450155_wp, & 0.1208650973866179E-2_wp, & -0.5395239384953E-5_wp /) !< x_gamm = xx y_gamm = x_gamm tmp = x_gamm + 5.5_wp tmp = ( x_gamm + 0.5_wp ) * LOG( tmp ) - tmp ser = 1.000000000190015_wp DO j = 1, 6 y_gamm = y_gamm + 1.0_wp ser = ser + cof( j ) / y_gamm ENDDO ! !-- Until this point the algorithm computes the logarithm of the gamma !-- function. Hence, the exponential function is used. ! gamm = EXP( tmp + LOG( stp * ser / x_gamm ) ) gamm = EXP( tmp ) * stp * ser / x_gamm RETURN END FUNCTION gamm END MODULE microphysics_mod