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C $Header: /u/gcmpack/MITgcm/pkg/thsice/thsice_albedo.F,v 1.2 2004/04/07 23:40:34 jmc Exp $ |
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C $Name: $ |
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#include "THSICE_OPTIONS.h" |
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CBOP |
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C !ROUTINE: THSICE_READPARMS |
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C !INTERFACE: |
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SUBROUTINE THSICE_ALBEDO( |
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I hi, hs, Tsf, age, |
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O albedo, |
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I myThid ) |
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C !DESCRIPTION: \bv |
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C *==========================================================* |
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C | S/R THSICE_ALBEDO |
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C *==========================================================* |
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C | Compute surface albedo |
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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 data == |
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#include "EEPARAMS.h" |
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#include "THSICE_PARAMS.h" |
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine Arguments == |
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_RL hi ! ice height |
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_RL hs ! snow height |
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_RL Tsf ! surface temperature |
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_RL age ! snow age |
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_RL albedo ! surface albedo |
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INTEGER myThid |
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CEOP |
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#ifdef ALLOW_THSICE |
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C == Local variables == |
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C frsnow :: fractional snow cover |
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C albsno :: albedo of snow |
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C albice :: albedo of ice |
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C albNewSnow :: albedo of new (fresh) snow |
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c _RL frsnow |
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_RL albsno, albice |
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_RL albNewSnow |
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C-- Albedo of Bare Sea-Ice |
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albice = albIceMax + (albIceMin-albIceMax)*exp(-hi/hAlbIce) |
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C-- LANL albedo calculation |
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c frsnow = 0. |
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c if (hs .gt. 0.) frsnow = 1. |
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c if (Tsf .lt. 0.) then |
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c albedo = frsnow*albColdSnow + (1.-frsnow)*albice |
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c else |
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c albedo = frsnow*albWarmSnow + (1.-frsnow)*albice |
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c endif |
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C-end LANL albedo calculation |
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C-- GISS model albedo calculation |
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c albice = 0.7 _d 0 |
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C- New snow: (linear) transition between -10.oC and 0.oC |
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C from cold/dry snow albedo to warm/wet snow albedo |
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albNewSnow = albColdSnow |
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& + (albWarmSnow - albColdSnow) |
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& *MAX( 0. _d 0, 1. _d 0 + MIN(Tsf/10. _d 0, 0. _d 0) ) |
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C- albedo of snow is function of snow-age (make age units into days): |
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albsno = albOldSnow |
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& +(albNewSnow-albOldSnow)*exp(-0.2 _d 0*age/86400. _d 0) |
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C- layer of snow over the ice: |
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albedo = albsno + (albice-albsno)*exp(-hs/hAlbSnow) |
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if (albedo.gt.1. _d 0 .or. albedo.lt. .2 _d 0) then |
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print*,'QQ - albedo problem', albedo, age, hs, albsno |
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stop |
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endif |
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#endif /* ALLOW_THSICE */ |
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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RETURN |
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END |
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