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dfer |
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C $Header: /u/gcmpack/MITgcm/pkg/land/land_albedo.F,v 1.1 2004/03/11 14:41:59 jmc Exp $ |
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jmc |
1.1 |
C $Name: $ |
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#include "LAND_OPTIONS.h" |
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CBOP |
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C !ROUTINE: LAND_DIAGNOSTICS |
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C !INTERFACE: |
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SUBROUTINE LAND_ALBEDO( |
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I land_frc, grnd_alb, |
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O alb_land, |
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I bi,bj, myTime, myIter, myThid ) |
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C !DESCRIPTION: \bv |
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C *==========================================================* |
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C | S/R LAND_ALBEDO |
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C | o Calculate snow albedo over land |
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C *==========================================================* |
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C \ev |
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C !USES: |
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IMPLICIT NONE |
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C == Global variables === |
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C-- size for MITgcm & Land package : |
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#include "LAND_SIZE.h" |
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#include "EEPARAMS.h" |
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#include "PARAMS.h" |
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#include "LAND_PARAMS.h" |
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#include "LAND_VARS.h" |
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine arguments == |
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C land_frc :: land fraction [0-1] |
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C grnd_alb :: ground albedo [0-1] |
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C alb_land :: albedo of land (including snow effect) [0-1] |
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C bi,bj :: Tile index |
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C myTime :: Current time of simulation ( s ) |
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C myIter :: Current iteration number in simulation |
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C myThid :: Number of this instance of the routine |
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_RS land_frc(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RS grnd_alb(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL alb_land(sNx,sNy) |
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INTEGER bi, bj, myIter, myThid |
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_RL myTime |
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CEOP |
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#ifdef ALLOW_LAND |
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C == Local Variables == |
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C i,j :: Loop counters |
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C albSnow :: albedo of snow |
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C ageSnow :: age of snow [days] |
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INTEGER i,j |
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_RL albSnow, ageSnow, hSnow, Tsf |
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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C- Compute albedo of snow and then albedo of land. |
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DO j=1,sNy |
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DO i=1,sNx |
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alb_land(i,j) = grnd_alb(i,j,bi,bj) |
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IF ( land_frc(i,j,bi,bj).GT.0. ) THEN |
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Tsf = land_skinT(i,j,bi,bj) |
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C snow age (units = days): |
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ageSnow = land_snowAge(i,j,bi,bj)/86400. _d 0 |
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hSnow = land_hSnow(i,j,bi,bj) |
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C-------------------------------------------- |
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C--- taken from thsice/thsice_albedo.F : |
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dfer |
1.2 |
C- New snow: (linear) transition between tempSnowAlbL (oC) and 0.oC |
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jmc |
1.1 |
C from cold/dry snow albedo to warm/wet snow albedo |
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dfer |
1.2 |
IF ( tempSnowAlbL.LT.0. _d 0 ) THEN |
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albSnow = albColdSnow |
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& + (albWarmSnow - albColdSnow) |
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& *MAX( 0. _d 0, MIN(1. _d 0 - Tsf/tempSnowAlbL, 1. _d 0) ) |
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ELSE |
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albSnow = albColdSnow |
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ENDIF |
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jmc |
1.1 |
C- albedo of snow is function of snow-age |
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albSnow = albOldSnow |
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& +(albSnow-albOldSnow)*exp(-0.2 _d 0*ageSnow) |
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C- layer of snow over the ground: |
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alb_land(i,j) = albSnow |
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& +(alb_land(i,j)-albSnow)*exp(-hSnow/hAlbSnow) |
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C-------------------------------------------- |
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ENDIF |
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ENDDO |
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ENDDO |
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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#endif /* ALLOW_LAND */ |
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RETURN |
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END |
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