!VERSION NUMBER: ! $Name: tikal $ ! $Id: wet_deposition_0D.F90,v 19.0 2012/01/06 20:09:12 fms Exp $ ! ! subroutine wet_deposition_0D( Henry_constant, Henry_variable, & frac_in_cloud, alpha_r, alpha_s, & T, p0, p1, rho_air, & cloud, rain, snow, & tracer, Lgas, Laerosol, Lice, & delta_tracer ) implicit none ! ! ! Routine to calculate the fraction of tracer removed by wet deposition ! ! ! ! Temperature (K) ! ! ! Pressure (Pa) at layer closer to surface ! ! ! Pressure (Pa) at layer farther from surface ! ! ! Air density (kg/m3) ! ! ! Cloud amount (liquid+ice) (kg/kg) ! ! ! Precipitation increment (rain) (kg/m3) ! ! ! Precipitation increment (snow) (kg/m3) ! ! ! The tracer field (tracer units) ! ! ! Is tracer a gas? ! ! ! Is tracer an aerosol? ! ! ! Is tracer removed by snow (or only by rain)? ! ! ! The change (increment) of the tracer field due to wet deposition (tracer units) !/OUT> ! ! Schemes allowed here are: ! ! 1) Removal according to Henry's Law. This law states that the ratio of the concentation in ! cloud water and the partial pressure in the interstitial air is a constant. In this ! instance, the units for Henry's constant are kg/L/Pa (normally it is M/L/Pa) ! Parameters for a large number of species can be found at ! http://www.mpch-mainz.mpg.de/~sander/res/henry.html ! ! 2) Aerosol removal, using specified in-cloud tracer fraction ! To utilize this section of code add one of the following lines as ! a method for the tracer of interest in the field table. !
! "wet_deposition","henry","henry=XXX, dependence=YYY"
! "wet_deposition","henry_below","henry=XXX, dependence=YYY"
!     where XXX is the Henry's constant for the tracer in question
!       and YYY is the temperature dependence of the Henry's Law constant.
!
! "wet_deposition","aerosol","frac_incloud=XXX"
! "wet_deposition","aerosol_below","frac_incloud=XXX"
!     where XXX is the in-cloud fraction of the aerosol tracer
!
! !----------------------------------------------------------------------- ! ... dummy arguments !----------------------------------------------------------------------- real, intent(in) :: Henry_constant, Henry_variable, & frac_in_cloud, alpha_r, alpha_s real, intent(in) :: T, p0, p1, rho_air real, intent(in) :: cloud, rain, snow real, intent(in) :: tracer logical, intent(in) :: Lgas, Laerosol, Lice real, intent(out) :: delta_tracer !----------------------------------------------------------------------- ! ... local variables !----------------------------------------------------------------------- real :: & Htemp, xliq, n_air, pwt, pmid, precip real :: & temp_factor, scav_factor, & w_h2o, beta, f_a, in_temp real, parameter :: & GRAV = 9.80, & ! acceleration due to gravity [m/s2] RDGAS = 287.04, & ! gas constant for dry air [J/kg/deg] AVOGNO = 6.023000E+23, & ! Avogadro's number inv298p15 = 1./298.15, & ! 1/K cm3_2_m3 = 1.e-6 ! m3/cm3 real, parameter :: mw_air = 28.96440E-03 ! molar mass of air (kg/mole) real, parameter :: mw_h2o = 18.0E-03 ! molar mass of H2O (kg/mole) !----------------------------------------------------------------------- delta_tracer = 0. pmid = 0.5 * (p0+p1) ! Pa pwt = ( p0 - p1 )/GRAV ! kg/m2 if( Lgas .or. Laerosol ) then !++lwh ! units = VMR ! ! Henry_constant (mole/L/Pa) = [X](aq) / Px(g) ! where [X](aq) is the concentration of tracer X in precipitation (mole/L) ! Px(g) is the partial pressure of the tracer in the air (Pa) ! ! VMR (total) = VMR (gas) + VMR (aq) ! = VMR (gas) + [X] * L ! ! where L = cloud liquid amount (kg H2O/mole air) ! ! Using Henry's Law, [X] = H * Px = H * VMR(gas) * Pfull ! ! So, VMR (total) = VMR(gas) * [ 1 + H * Pfull * L ] ! ! VMR(gas) = VMR(total) / [1 + H * Pfull * L] ! ! [X] = H * Pfull * VMR(total) / [ 1 + H * Pfull * L] ! ! Following Giorgi and Chameides, JGR, 90(D5), 1985, the first-order loss ! rate constant (s^-1) of X due to wet deposition equals: ! ! k = W_X / n_X ! ! where W_x = the loss rate (molec/cm3/s), and n_X = the number density (molec/cm3) ! ! W_X = [X] * W_H2O / (55 mole/L) ! n_x = VMR(total) * n_air (molec/cm3) = VMR(total) * P/(kT) * 1E-6 m3/cm3 ! ! where P = atmospheric pressure (Pa) ! k = Boltzmann's constant = 1.38E-23 J/K ! T = temperature (K) ! W_H2O = removal increment of water (molec/cm3) ! ! [X] * W_H2O / 55 ! So, k = ------------------------------ ! VMR(total) * P/(kT) * 1E-6 ! ! W_H2O H * VMR(total) * P / [ 1 + H * P *L ] ! = ----- * --------------------------------------- ! 55 VMR(total) * P/(kT) * 1E-6 ! ! W_H2O H * kT * 1E6 ! = ----- * ------------- ! 55 1 + H * P * L ! ! W_H2O 1 1 H * P * L ! = ----- * ----- * - * ------------- ! 55 n_air L 1 + H * P * L ! ! where W_H2O = precip (kg/m3) * (AVOGNO/mw_h2o) (molec/kg) * 1E-6 m3/cm3 ! if( (Lgas .and. Henry_constant > 0.) .or. Laerosol ) then if (Lice) then precip = rain+snow else precip = rain end if in_temp = 0. scav_factor = 0.0 xliq = MAX( cloud * mw_air, 0. ) ! (kg H2O)/(mole air) n_air = rho_air * (AVOGNO/mw_air) * cm3_2_m3 ! molec/cm3 if (Lgas) then ! Calculate the temperature dependent Henry's Law constant temp_factor = 1/T-inv298p15 Htemp = Henry_constant * exp( Henry_variable*temp_factor ) f_a = Htemp * pmid * xliq scav_factor = f_a / ( 1.+f_a ) else if (Laerosol) then scav_factor = frac_in_cloud end if if (precip > 0. .and. xliq > 0.) then w_h2o = precip * (AVOGNO/mw_h2o) * cm3_2_m3 ! molec/cm3 beta = w_h2o * mw_h2o / (n_air * xliq) ! fraction of condensed water removed beta = MAX(MIN(beta,1.),0.) in_temp = beta * scav_factor ! fraction of tracer removed end if ! wdep_in = - in_temp*tracer*pwt ! dt_temp = 1. - exp( -in_temp*dt ) ! fractional loss/timestep ! tracer_dt = dt_temp / dt !+ve loss frequency (1/sec) delta_tracer = in_temp ! fraction of tracer removed !--lwh endif end if ! Now multiply by the tracer mixing ratio to get the actual tendency. ! tracer_dt = MIN( MAX(tracer_dt, 0.0E+00), 0.5/dt) if (tracer > 0.) then delta_tracer = delta_tracer*tracer else delta_tracer = 0. end if ! Output diagnostics in kg/m2/s (if MMR) or mole/m2/s (if VMR) ! if(trim(units) .eq. 'mmr') then ! diag_scale = 1. ! else if(trim(units) .eq. 'vmr') then ! diag_scale = mw_air ! kg/mole ! else ! write(*,*) ' Tracer number =',n,' tracer_name=',tracer_name ! write(*,*) ' scheme=',text_in_scheme ! write(*,*) ' control=',control ! write(*,*) ' scheme=',scheme ! write(*,*) 'Please check field table' ! write(*,*) 'tracers units =',trim(units),'it should be either mmr or vmr!' ! ! Tracer units must be either VMR or MMR ! ! call error_mesg('wet_deposition', 'Unsupported tracer units.', FATAL ) ! end if ! if(trim(cloud_param) == 'donner') then ! if (id_tracer_wdep_donin(n) > 0 ) then ! used = send_data ( id_tracer_wdep_donin(n), wdep_in/diag_scale, Time, is_in=is, js_in=js) ! endif ! if(id_tracer_wdep_donin_dt(n) > 0) then ! used = send_data ( id_tracer_wdep_donin_dt(n), in_temp, Time, is_in=is, js_in=js, ks_in=1) ! endif ! if(id_tracer_wdep_don_dt(n) > 0) then ! used = send_data ( id_tracer_wdep_don_dt(n), dt_temp/dt, Time, is_in=is, js_in=js, ks_in=1) ! endif ! endif end subroutine wet_deposition_0D !