Changeset 734 for trunk/LMDZ.MARS/libf

Timestamp:

Jul 23, 2012, 1:15:11 PM (12 years ago)

Author:

tnavarro

Message:

scheme for latent heat release of surface ice was wrong. corrected

File:

• trunk/LMDZ.MARS/libf/phymars/vdifc.F (modified) (2 diffs)

trunk/LMDZ.MARS/libf/phymars/vdifc.F

@@ -113 +113 @@
 c     For latent heat release from ground ice sublimation    
       REAL tsrf_lw(ngridmx)
+      REAL alpha
       REAL T1,T2
       SAVE T1,T2
-      DATA T1,T2/-877.5,807.5/ ! zeros of latent heat equation for ice
+      DATA T1,T2/-604.3,1080.7/ ! zeros of latent heat equation for ice
 
 c    Tracers :
@@ -814 +815 @@
 c             We solve dT/dt = (2834.3-0.28*(T-To)-0.004*(T-To)^2)*1e3*iceflux/cpp
               tsrf_lw(ig) = ptsrf(ig) + pdtsrf(ig) *ptimestep
-              
-              tsrf_lw(ig) = (T1+T2)*(T1+T2) 
-     &       -  4*(T2*T1 - (tsrf_lw(ig)-T1)*(tsrf_lw(ig)-T2)*
-     &            exp( -0.25*abs(T1-T2)*pdqsdif(ig,igcm_h2o_ice)
-     &            *ptimestep/pcapcal(ig)) )        
-              tsrf_lw(ig) = (T1+T2)/2 +  sqrt(tsrf_lw(ig))/2 ! surface temperature at t+1
+             
+              alpha = exp(-4*abs(T1-T2)*pdqsdif(ig,igcm_h2o_ice)
+     &            *ptimestep/pcapcal(ig))
+
+              tsrf_lw(ig) = (tsrf_lw(ig)*(T2-alpha*T1)+T1*T2*(alpha-1))
+     &                      /(tsrf_lw(ig)*(1-alpha)+alpha*T2-T1)  ! surface temperature at t+1
 
               pdtsrf(ig) = (tsrf_lw(ig)-ptsrf(ig))/ptimestep