Changeset 5041 for LMDZ6/branches/cirrus

Timestamp:

Jul 10, 2024, 2:57:53 PM (4 months ago)

Author:

aborella

Message:

Added capa_cond_cirrus tuning parameter

Location:

LMDZ6/branches/cirrus/libf/phylmd

Files:

• lmdz_lscp_condensation.F90 (modified) (4 diffs)
• lmdz_lscp_ini.F90 (modified) (3 diffs)

LMDZ6/branches/cirrus/libf/phylmd/lmdz_lscp_condensation.F90

@@ -121 +121 @@
 USE lmdz_lscp_ini,        ONLY: lunout
 
-USE lmdz_lscp_ini,        ONLY: mu_subl_pdf_lscp, beta_pdf_lscp, temp_thresh_pdf_lscp, &
+USE lmdz_lscp_ini,        ONLY: capa_cond_cirrus, mu_subl_pdf_lscp, beta_pdf_lscp, temp_thresh_pdf_lscp, &
                                 rhlmid_pdf_lscp, k0_pdf_lscp, kappa_pdf_lscp, rhl0_pdf_lscp, &
                                 cond_thresh_pdf_lscp, coef_mixing_lscp, coef_shear_lscp, & 
@@ -384 +384 @@
         !
         !--The deposition equation is
-        !-- dmi/dt = alpha*4pi*C*Svi / ( R*T/esi/Mw/Dv + Ls/ka/T * (Ls*Mw/R/T - 1) )
-        !--from Pruppacher and Klett (2010), where
+        !-- dmi/dt = alpha*4pi*C*Svi / ( R_v*T/esi/Dv + Ls/ka/T * (Ls/R_v/T - 1) )
+        !--from Lohmann et al. (2016), where
+        !--alpha is the deposition coefficient [-]
         !--mi is the mass of one ice crystal [kg]
         !--C is the capacitance of an ice crystal [m]
         !--Svi is the supersaturation ratio equal to (qvc - qsat)/qsat [-]
-        !--R is the perfect gas constant [J/mol/K]
+        !--R_v is the specific gas constant for humid air [J/kg/K]
         !--T is the temperature [K]
         !--esi is the saturation pressure w.r.t. ice [Pa]
-        !--Mw is the molar mass of water [kg/mol]
         !--Dv is the diffusivity of water vapor [m2/s]
         !--Ls is the specific latent heat of sublimation [J/kg/K]
         !--ka is the thermal conductivity of dry air [J/m/s/K]
         !
+        !--We fix alpha = 0.5 following Lohmann et al. (2016)
+        !--The capacitance of the ice crystals is proportional to a parameter capa_cond_cirrus
+        !-- C = capa_cond_cirrus * r_ice
+        !
         !--We have qice = Nice * mi, where Nice is the ice crystal
         !--number concentration per kg of moist air
         !--HYPOTHESIS 1: the ice crystals are spherical, therefore
-        !-- C = r_ice
         !-- mi = 4/3 * pi * r_ice**3 * rho_ice
         !--HYPOTHESIS 2: the ice crystals are monodisperse with the
@@ -416 +419 @@
         !
         !--The deposition equation then reads:
-        !-- dqi/dt = alpha*4pi*r_ice*(qvc-qsat)/qsat / ( R*T/esi/Mw/Dv + Ls/ka/T * (Ls*Mw/R/T - 1) ) * Nice
-        !-- dqi/dt = alpha*4pi* (qi / qi_0)**(1/3) *r_ice_0*(qvc-qsat)/qsat &
+        !-- dqi/dt = alpha*4pi*capa_cond_cirrus*r_ice*(qvc-qsat)/qsat / ( R_v*T/esi/Dv + Ls/ka/T * (Ls/R_v/T - 1) ) * Nice
+        !-- dqi/dt = alpha*4pi*capa_cond_cirrus* (qi / qi_0)**(1/3) *r_ice_0*(qvc-qsat)/qsat &
         !--             / ( R_v*T/esi/Dv + Ls/ka/T * (Ls*R_v/T - 1) ) &
         !--                         * qi_0 / ( 4/3 RPI r_ice_0**3 rho_ice )
         !-- dqi/dt = qi**(1/3) * (qvc - qsat) * qi_0**(2/3) &
-        !--  *alpha/qsat/ (R_v*T/esi/Dv + Ls/ka/T*(Ls*R_v/T - 1)) / ( 1/3 r_ice_0**2 rho_ice )
+        !--  *alpha/qsat*capa_cond_cirrus/ (R_v*T/esi/Dv + Ls/ka/T*(Ls*R_v/T - 1)) / ( 1/3 r_ice_0**2 rho_ice )
         !--and we have
         !-- dqvc/dt = - qi**(1/3) * (qvc - qsat) / kappa * qi_0**(2/3) / r_ice_0**2
         !-- dqi/dt  =   qi**(1/3) * (qvc - qsat) / kappa * qi_0**(2/3) / r_ice_0**2
-        !--where kappa = (2/3*rho_ice)*qsat*(R_v*T/esi/Dv + Ls/ka/T*(Ls/R_v/T - 1))
+        !--where kappa = (2/3*rho_ice)/capa_cond_cirrus*qsat*(R_v*T/esi/Dv + Ls/ka/T*(Ls/R_v/T - 1))
+        !--having replaced alpha = 0.5 in the formula
         !
         !--This system of equations can be resolved with an exact
@@ -440 +444 @@
         !--This formula for water vapor diffusivity comes from Hall and Pruppacher (1976)
         water_vapor_diff = 0.211 * ( temp(i) / RTT )**1.94 * ( 101325. / pplay(i) ) * 1.e-4
-        kappa = 2. / 3. * rho_ice * qsat(i) &
+        kappa = 2. / 3. * rho_ice / capa_cond_cirrus * qsat(i) &
               * ( RV * temp(i) / water_vapor_diff / pres_sat &
                 + RLSTT / air_thermal_conduct / temp(i) * ( RLSTT / RV / temp(i) - 1. ) )
+        !--NB. the greater kappa, the lower the efficiency of the deposition/sublimation process
       ENDIF
 

LMDZ6/branches/cirrus/libf/phylmd/lmdz_lscp_ini.F90

@@ -154 +154 @@
   INTEGER, SAVE, PROTECTED :: iflag_cloud_sublim_pdf=3       ! iflag for the distribution of water inside ice clouds
   !$OMP THREADPRIVATE(iflag_cloud_sublim_pdf)
+
+  REAL, SAVE, PROTECTED :: capa_cond_cirrus=1.               ! [-] capacitance factor for growth/sublimation of ice crystals in cirrus clouds
+  !$OMP THREADPRIVATE(capa_cond_cirrus)
 
   REAL, SAVE, PROTECTED :: mu_subl_pdf_lscp=1./3.            ! [-] shape factor of the gamma distribution of water inside ice clouds
@@ -389 +392 @@
     CALL getin_p('ok_weibull_warm_clouds',ok_weibull_warm_clouds)
     CALL getin_p('iflag_cloud_sublim_pdf',iflag_cloud_sublim_pdf)
+    CALL getin_p('capa_cond_cirrus',capa_cond_cirrus)
     CALL getin_p('mu_subl_pdf_lscp',mu_subl_pdf_lscp)
     CALL getin_p('beta_pdf_lscp',beta_pdf_lscp)
@@ -463 +467 @@
     WRITE(lunout,*) 'lscp_ini, ok_weibull_warm_clouds:', ok_weibull_warm_clouds
     WRITE(lunout,*) 'lscp_ini, iflag_cloud_sublim_pdf:', iflag_cloud_sublim_pdf
+    WRITE(lunout,*) 'lscp_ini, capa_cond_cirrus:', capa_cond_cirrus
     WRITE(lunout,*) 'lscp_ini, mu_subl_pdf_lscp:', mu_subl_pdf_lscp
     WRITE(lunout,*) 'lscp_ini, beta_pdf_lscp:', beta_pdf_lscp