Changeset 5437 for LMDZ6/trunk/libf/phylmd

Timestamp:

Dec 20, 2024, 2:10:34 PM (13 hours ago)

Author:

evignon

Message:

nouveaux ajustements param cirrus pour mieux coller aux notations du papier, A Borella

Location:

LMDZ6/trunk/libf/phylmd

Files:

• lmdz_lscp_condensation.f90 (modified) (3 diffs)
• lmdz_lscp_ini.f90 (modified) (1 diff)

LMDZ6/trunk/libf/phylmd/lmdz_lscp_condensation.f90

@@ -230 +230 @@
 REAL :: dqvc_mix_sub, dqvc_mix_issr
 REAL :: dqt_mix
-REAL :: a_mix, bovera, N_cld_mix, L_mix
+REAL :: a_mix, bovera, Povera, N_cld_mix, L_mix
 REAL :: envfra_mix, cldfra_mix
 REAL :: L_shear, shear_fra
@@ -665 +665 @@
         !--Clouds within the mesh are assumed to be ellipses. The length of the
         !--semi-major axis is a and the length of the semi-minor axis is b.
-        !--N_cld_mix is the number of clouds within the mesh, and
+        !--N_cld_mix is the number of clouds in contact with clear sky, and can be non-integer.
+        !--In particular, it is 0 if cldfra = 1.
         !--clouds_perim is the total perimeter of the clouds within the mesh,
         !--not considering interfaces with other meshes (only the interfaces with clear
@@ -684 +685 @@
         !-- b / a = bovera = MAX(0.1, cldfra)
         bovera = MAX(0.1, cldfra(i))
+        !--P / a is a function of b / a only, that we can calculate
+        !-- P / a = RPI * ( 3. * ( 1. + b / a ) - SQRT( (3. + b / a) * (1. + 3. * b / a) ) )
+        Povera = RPI * ( 3. * (1. + bovera) - SQRT( (3. + bovera) * (1. + 3. * bovera) ) )
         !--The clouds perimeter is imposed using the formula from Morcrette 2012,
         !--based on observations.
-        !-- clouds_perim_normalized = alpha * cldfra * ( 1. - cldfra ) = clouds_perim / ( norm_constant * cell_area )
-        !--
-        !--With all this, we have
-        !-- a = SQRT( cell_area * cldfra / ( b / a * N_cld_mix * RPI ) )
-        !-- P = RPI * a * ( 3. * ( 1. + b / a ) - SQRT( (3. + b / a) * (1. + 3. * b / a) ) )
-        !--and therefore, using the perimeter
-        !-- alpha * cldfra * ( 1. - cldfra ) * norm_constant * cell_area
-        !--             = N_cld_mix * RPI &
-        !--             * SQRT( cell_area * cldfra / ( b / a * N_cld_mix * RPI ) ) &
-        !--             * ( 3. * ( 1. + b / a ) - SQRT( (3. + b / a) * (1. + 3. * b / a) ) )
-        !--and finally
-        N_cld_mix = coef_mixing_lscp * cldfra(i) * ( 1. - cldfra(i) )**2 &
-                  * cell_area(i) * bovera / RPI &
-                  / ( 3. * (1. + bovera) - SQRT( (3. + bovera) * (1. + 3. * bovera) ) )**2
-        !--where coef_mix_lscp = ( alpha * norm_constant )**2
-        !--N_cld_mix is the number of clouds in contact with clear sky, and can be non-integer
-        !--In particular, it is 0 if cldfra = 1
-        a_mix = SQRT( cell_area(i) * cldfra(i) / bovera / N_cld_mix / RPI )
+        !-- clouds_perim / cell_area = N_cld_mix * ( P / a * a ) / cell_area = coef_mix_lscp * cldfra * ( 1. - cldfra )
+        !--With cldfra = a * ( b / a * a ) * RPI * N_cld_mix / cell_area, we have:
+        !-- cldfra = a * b / a * RPI / (P / a) * coef_mix_lscp * cldfra * ( 1. - cldfra )
+        !-- a = (P / a) / ( coef_mix_lscp * RPI * ( 1. - cldfra ) * (b / a) )
+        a_mix = Povera / coef_mixing_lscp / RPI / ( 1. - cldfra(i) ) / bovera
+        !--and finally,
+        !-- N_cld_mix = coef_mix_lscp * cldfra * ( 1. - cldfra ) * cell_area / ( P / a * a )
+        N_cld_mix = coef_mixing_lscp * cldfra(i) * ( 1. - cldfra(i) ) * cell_area(i) &
+                  / Povera / a_mix
 
         !--The time required for turbulent diffusion to homogenize a region of size

LMDZ6/trunk/libf/phylmd/lmdz_lscp_ini.f90

@@ -195 +195 @@
   !$OMP THREADPRIVATE(delta_hetfreez)
   
-  REAL, SAVE, PROTECTED :: coef_mixing_lscp=9.E-8            ! [-] tuning coefficient for the mixing process
+  REAL, SAVE, PROTECTED :: coef_mixing_lscp=1.E-3            ! [-] tuning coefficient for the mixing process
   !$OMP THREADPRIVATE(coef_mixing_lscp)