Changeset 2041 for trunk/LMDZ.MARS

Timestamp:

Nov 14, 2018, 4:38:52 PM (6 years ago)

Author:

flefevre

Message:

Photolyse on-line : Mise a jour de la section efficace Rayleigh (Itiaksov et al., 2008)

Location:

trunk/LMDZ.MARS/libf/aeronomars

Files:

• photolysis_mod.F90 (modified) (3 diffs)
• photolysis_online.F (modified) (2 diffs)

trunk/LMDZ.MARS/libf/aeronomars/photolysis_mod.F90

@@ -15 +15 @@
 
   integer, parameter :: nw = 162          ! number of spectral intervals (low-res)
-  integer :: mopt                         ! high-res/low-res switch
+  integer, save :: mopt                   ! high-res/low-res switch
 
   real, dimension(nw), save :: wl, wc, wu ! lower, center, upper wavelength for each interval
@@ -248 +248 @@
 
       wincr = 5.0
-      DO iw = 80, 80, 5
+      DO iw = 80, 80
         kw = kw + 1
         wl(kw) = real(iw)
@@ -265 +265 @@
       END DO
 
-! define wavelength intervals of width 5.0 nm from 117 to 120 nm:
+! define wavelength intervals of width 3.0 nm from 117 to 120 nm:
 
       wincr = 3.0
-      DO iw = 117, 117, 3
+      DO iw = 117, 117
         kw = kw + 1
         wl(kw) = real(iw)

trunk/LMDZ.MARS/libf/aeronomars/photolysis_online.F

@@ -260 +260 @@
       real, parameter :: avo = 6.022e23
       real, parameter :: g = 3.72
-      real :: dp
-      real :: alpha, rho, df, pi
+      real :: dp, nu
       real, dimension(nw) :: srayl
       integer :: ilev, iw
@@ -275 +274 @@
       do iw = 1, nw - 1
 
-!        calcul de section efficace Rayleigh: voir Atreya and Gu, JGR, 
-!        13133-13145, 1994.
-!
-!        rho   : normal depolarization ratio       = 0.0774        for CO2
-!        df    : depolarization factor
-!        alpha : average dielectric polarizability = 2.911e-24 cm3 for CO2
-
-         pi    = acos(-1.0)
-         rho   = 0.0774
-         alpha = 2.911e-24*1.e21  ! nm3
-
-         df = (6. + 3.*rho)/(6. - 7.*rho)
-
-         srayl(iw) = 8.*pi/3.*((2.*pi/wc(iw))**4)*(alpha**2)*df   ! nm2
+!        co2 rayleigh cross-section
+!        ityaksov et al., chem. phys. lett., 462, 31-34, 2008
+
+         nu = 1./(wc(iw)*1.e-7)
+         srayl(iw) = 1.78e-26*nu**(4. + 0.625)
+         srayl(iw) = srayl(iw)*1.e-20 ! cm2
 
          do ilev = 1, nlev
-            dtrl(ilev,iw) = colinc(ilev)*srayl(iw)*1.e-14     ! cm2
+            dtrl(ilev,iw) = colinc(ilev)*srayl(iw)   ! cm2
          end do
       end do