1 | ! |
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2 | ! $Id: aer_sedimnt.F90 4950 2024-05-22 13:16:36Z abarral $ |
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3 | ! |
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4 | SUBROUTINE AER_SEDIMNT(pdtphys, t_seri, pplay, paprs, tr_seri, dens_aer) |
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5 | |
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6 | !**** *AER_SEDIMNT* - ROUTINE FOR PARAMETRIZATION OF AEROSOL SEDIMENTATION |
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7 | |
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8 | ! Christoph Kleinschmitt |
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9 | ! based on the sedimentation scheme of |
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10 | ! Olivier Boucher & Jean-Jacques Morcrette |
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11 | ! (following the ice sedimentation scheme of Adrian Tompkins) |
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12 | |
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13 | !** INTERFACE. |
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14 | ! ---------- |
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15 | ! *AER_SEDIMNT* IS CALLED FROM *traccoag_mod*. |
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16 | |
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17 | !----------------------------------------------------------------------- |
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18 | |
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19 | USE phys_local_var_mod, ONLY: mdw, budg_sed_part, DENSO4, DENSO4B, f_r_wet, f_r_wetB, vsed_aer |
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20 | USE strataer_local_var_mod, ONLY: flag_new_strat_compo |
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21 | USE dimphy, ONLY : klon,klev |
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22 | USE infotrac_phy |
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23 | USE aerophys |
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24 | USE YOMCST |
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25 | |
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26 | IMPLICIT NONE |
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27 | |
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28 | !----------------------------------------------------------------------- |
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29 | |
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30 | ! transfer variables when calling this routine |
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31 | REAL,INTENT(IN) :: pdtphys ! Pas d'integration pour la physique (seconde) |
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32 | REAL,DIMENSION(klon,klev),INTENT(IN) :: t_seri ! Temperature |
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33 | REAL,DIMENSION(klon,klev),INTENT(IN) :: pplay ! pression pour le mileu de chaque couche (en Pa) |
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34 | REAL,DIMENSION(klon,klev+1),INTENT(IN) :: paprs ! pression pour chaque inter-couche (en Pa) |
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35 | REAL,DIMENSION(klon,klev,nbtr),INTENT(INOUT):: tr_seri ! Concentration Traceur [U/KgA] |
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36 | REAL,DIMENSION(klon,klev) :: dens_aer! density of aerosol particles [kg/m3 aerosol] with default H2SO4 mass |
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37 | |
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38 | ! local variables in sedimentation routine |
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39 | INTEGER :: JL,JK,nb |
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40 | REAL,DIMENSION(klon,klev) :: zvis ! dynamic viscosity of air [kg/(m*s)] |
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41 | REAL,DIMENSION(klon,klev) :: zlair ! mean free path of air [m] |
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42 | REAL :: ZRHO ! air density [kg/m^3] |
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43 | REAL :: ZGDP ! =g/dp=1/(rho*dz) |
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44 | REAL :: ZDTGDP ! =dt/(rho*dz) |
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45 | REAL,DIMENSION(klon,nbtr_bin) :: ZSEDFLX ! sedimentation flux of tracer [U/(m^2*s)] |
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46 | REAL,DIMENSION(nbtr_bin) :: ZAERONW ! tracer concentration at current time step [U/KgA] |
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47 | REAL,DIMENSION(klon,nbtr_bin) :: ZAERONWM1! tracer concentration at preceding time step [U/KgA] |
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48 | REAL,DIMENSION(klon,klev,nbtr_bin) :: ZVAER ! sedimentation velocity [m/s] |
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49 | REAL,DIMENSION(nbtr_bin) :: ZSOLAERS ! sedimentation flux arriving from above [U/(m^2*s)] |
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50 | REAL,DIMENSION(nbtr_bin) :: ZSOLAERB ! sedimentation flux leaving gridbox [U/(m^2*s)] |
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51 | REAL,DIMENSION(klon,klev) :: m_sulf |
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52 | |
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53 | ! dynamic viscosity of air (Pruppacher and Klett, 1978) [kg/(m*s)] |
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54 | WHERE (t_seri.GE.273.15) |
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55 | zvis=(1.718 + 0.0049*(t_seri-273.15))*1.E-5 |
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56 | ELSEWHERE |
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57 | zvis=(1.718 + 0.0049*(t_seri-273.15)-1.2E-05*(t_seri-273.15)**2)*1.E-5 |
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58 | END WHERE |
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59 | |
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60 | ! mean free path of air (Prupp. Klett) [m] |
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61 | zlair(:,:) = 0.066 *(1.01325E+5/pplay(:,:))*(t_seri(:,:)/293.15)*1.E-06 |
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62 | |
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63 | !--initialisations of variables carried out from one layer to the next layer |
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64 | !--actually not needed if (JK>1) test is on |
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65 | DO JL=1,klon |
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66 | DO nb=1,nbtr_bin |
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67 | ZSEDFLX(JL,nb)=0.0 |
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68 | ZAERONWM1(JL,nb)=0.0 |
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69 | ENDDO |
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70 | ENDDO |
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71 | |
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72 | !--from top to bottom (!) |
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73 | DO JK=klev,1,-1 |
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74 | DO JL=1,klon |
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75 | DO nb=1,nbtr_bin |
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76 | !--initialisations |
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77 | ZSOLAERS(nb)=0.0 |
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78 | ZSOLAERB(nb)=0.0 |
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79 | ZGDP=RG/(paprs(JL,JK)-paprs(JL,JK+1)) |
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80 | ZDTGDP=pdtphys*ZGDP |
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81 | |
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82 | ! source from above |
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83 | IF (JK<klev) THEN |
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84 | ZSEDFLX(JL,nb)=ZSEDFLX(JL,nb)*ZAERONWM1(JL,nb) |
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85 | ZSOLAERS(nb)=ZSOLAERS(nb)+ZSEDFLX(JL,nb)*ZDTGDP |
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86 | ENDIF |
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87 | |
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88 | ! sink to next layer |
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89 | ZRHO=pplay(JL,JK)/(RD*t_seri(JL,JK)) |
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90 | |
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91 | ! stokes-velocity with cunnigham slip- flow correction |
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92 | IF(flag_new_strat_compo) THEN |
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93 | ! stokes-velocity with cunnigham slip- flow correction |
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94 | ZVAER(JL,JK,nb) = 2./9.*(DENSO4B(JL,JK,nb)*1000.-ZRHO)*RG/zvis(JL,JK)*(f_r_wetB(JL,JK,nb)*mdw(nb)/2.)**2.* & |
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95 | (1.+ 2.*zlair(JL,JK)/(f_r_wetB(JL,JK,nb)*mdw(nb))*(1.257+0.4*EXP(-0.55*f_r_wetB(JL,JK,nb)*mdw(nb)/zlair(JL,JK)))) |
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96 | ELSE |
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97 | ZVAER(JL,JK,nb) = 2./9.*(DENSO4(JL,JK)*1000.-ZRHO)*RG/zvis(JL,JK)*(f_r_wet(JL,JK)*mdw(nb)/2.)**2.* & |
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98 | (1.+ 2.*zlair(JL,JK)/(f_r_wet(JL,JK)*mdw(nb))*(1.257+0.4*EXP(-0.55*f_r_wet(JL,JK)*mdw(nb)/zlair(JL,JK)))) |
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99 | ENDIF |
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100 | |
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101 | ZSEDFLX(JL,nb)=ZVAER(JL,JK,nb)*ZRHO |
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102 | ZSOLAERB(nb)=ZSOLAERB(nb)+ZDTGDP*ZSEDFLX(JL,nb) |
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103 | |
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104 | !---implicit solver |
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105 | ZAERONW(nb)=(tr_seri(JL,JK,nb+nbtr_sulgas)+ZSOLAERS(nb))/(1.0+ZSOLAERB(nb)) |
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106 | |
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107 | !---new time-step AER variable needed for next layer |
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108 | ZAERONWM1(JL,nb)=ZAERONW(nb) |
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109 | |
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110 | tr_seri(JL,JK,nb+nbtr_sulgas)=ZAERONWM1(JL,nb) |
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111 | ENDDO |
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112 | ENDDO |
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113 | ENDDO |
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114 | |
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115 | !---sedimentation flux to the surface |
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116 | !---ZAERONWM1 now contains the surface concentration at the new timestep |
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117 | !---PFLUXAER in unit of xx m-2 s-1 |
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118 | budg_sed_part(:)=0.0 |
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119 | DO JL=1,klon |
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120 | ZRHO=pplay(JL,1)/(RD*t_seri(JL,1)) |
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121 | DO nb=1,nbtr_bin |
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122 | !compute budg_sed_part as sum over bins in kg(S)/m2/s |
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123 | budg_sed_part(JL)=budg_sed_part(JL)+ZRHO*ZAERONWM1(JL,nb)*ZVAER(JL,1,nb)*(mSatom/mH2SO4mol) & |
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124 | & *dens_aer_dry*4./3.*RPI*(mdw(nb)/2.)**3 |
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125 | ENDDO |
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126 | ENDDO |
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127 | |
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128 | vsed_aer(:,:)=0.0 |
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129 | m_sulf(:,:)=0.0 |
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130 | |
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131 | DO nb=1,nbtr_bin |
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132 | !compute mass-weighted mean of sedimentation velocity |
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133 | vsed_aer(:,:)=vsed_aer(:,:)+ZVAER(:,:,nb)*(mdw(nb)/2.)**3*MAX(1.e-30, tr_seri(:,:,nb+nbtr_sulgas)) |
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134 | m_sulf(:,:)=m_sulf(:,:)+(mdw(nb)/2.)**3*MAX(1.e-30, tr_seri(:,:,nb+nbtr_sulgas)) |
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135 | ENDDO |
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136 | |
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137 | !divide by total aerosol mass in grid cell |
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138 | vsed_aer(:,:)=vsed_aer(:,:)/m_sulf(:,:) |
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139 | |
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140 | END SUBROUTINE AER_SEDIMNT |
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