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gforget |
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C $Header: /u/gcmpack/MITgcm/pkg/seaice/seaice_budget_ice.F,v 1.3 2006/12/19 18:57:09 dimitri Exp $ |
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C $Name: $ |
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#include "SEAICE_OPTIONS.h" |
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CStartOfInterface |
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SUBROUTINE SEAICE_BUDGET_ICE( |
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I UG, HICE_ACTUAL, HSNOW_ACTUAL, |
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U TSURF, |
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O F_io_net,F_ia_net,F_ia, IcePenetratingShortwaveFlux, |
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I bi, bj ) |
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C /================================================================\ |
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C | SUBROUTINE seaice_budget_ice | |
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C | o Calculate ice growth rate, surface fluxes and temperature of | |
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C | ice surface. | |
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C | see Hibler, MWR, 108, 1943-1973, 1980 | |
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C |================================================================| |
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C \================================================================/ |
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IMPLICIT NONE |
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C === Global variables === |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "FFIELDS.h" |
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#include "SEAICE_PARAMS.h" |
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#include "SEAICE_FFIELDS.h" |
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#ifdef SEAICE_VARIABLE_FREEZING_POINT |
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#include "DYNVARS.h" |
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#endif /* SEAICE_VARIABLE_FREEZING_POINT */ |
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C === Routine arguments === |
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C INPUT: |
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C UG :: thermal wind of atmosphere |
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C TSURF :: surface temperature of ice in Kelvin, updated |
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C HICE_ACTUAL :: (actual) ice thickness with upper and lower limit |
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C HSNOW_ACTUAL :: actual snow thickness |
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C bi,bj :: loop indices |
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C OUTPUT: |
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C netHeatFlux :: net heat flux under ice = growth rate |
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C IcePenetratingShortwaveFlux :: short wave heat flux under ice |
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_RL UG (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL TSURF (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL HICE_ACTUAL (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL HSNOW_ACTUAL (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_ia (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_io_net (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_ia_net (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_swi (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_lwd (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_lwu (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_lh (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_sens (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL F_c (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL qhice_mm (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL IcePenetratingShortwaveFlux (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL AbsorbedShortwaveFlux (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL IcePenetratingShortwaveFluxFraction |
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& (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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INTEGER bi, bj |
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INTEGER KOPEN |
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C === Local variables === |
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C i,j - Loop counters |
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INTEGER i, j |
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INTEGER ITER |
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_RL QS1, C1, C2, C3, C4, C5, TB, D1, D1I, D3,IAN1 |
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_RL TMELT, TMELTP, XKI, XKS, HCUT, ASNOW, XIO |
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C effective conductivity of combined ice and snow |
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_RL effConduct |
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C specific humidity at ice surface |
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_RL mm_pi,mm_log10pi,dqhice_dTice |
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C powers of temperature |
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_RL t1, t2, t3, t4 |
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C local copies of global variables |
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_RL tsurfLoc (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL atempLoc (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL lwdownLoc (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL ALB (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL tsurfLocOld |
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c Ian Saturation Vapor Pressure |
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_RL aa1,aa2,bb1,bb2,Ppascals,cc0,cc1,cc2,cc3t,dFiDTs1 |
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aa1 = 2663.5 |
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aa2 = 12.537 |
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bb1 = 0.622 |
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bb2 = 1.0 - bb1 |
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Ppascals = 1000.*100. |
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cc0 = 10**aa2 |
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cc1 = cc0*aa1*bb1*Ppascals*log(10.0) |
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cc2 = cc0*bb2 |
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C FREEZING TEMPERATURE OF SEAWATER |
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TB=273.15 _d + 00 - 1.96 _d + 00 |
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C SENSIBLE HEAT CONSTANT |
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D1=SEAICE_sensHeat |
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C ICE LATENT HEAT CONSTANT |
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D1I=SEAICE_latentIce |
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C STEFAN BOLTZMAN CONSTANT TIMES 0.97 EMISSIVITY |
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D3=SEAICE_emissivity |
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C MELTING TEMPERATURE OF ICE |
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TMELT=273.15 _d +00 |
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C ICE CONDUCTIVITY |
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XKI=2.0340 |
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C SNOW CONDUCTIVITY |
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XKS=SEAICE_snowConduct |
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C CUTOFF SNOW THICKNESS |
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HCUT=SEAICE_snowThick |
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C PENETRATION SHORTWAVE RADIATION FACTOR |
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XIO=SEAICE_shortwave |
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DO J=1,sNy |
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DO I=1,sNx |
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IcePenetratingShortwaveFlux (I,J) = 0. _d 0 |
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IcePenetratingShortwaveFluxFraction (I,J) = 0. _d 0 |
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AbsorbedShortwaveFlux (I,J) = 0. _d 0 |
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qhice_mm (I,J) = 0.0 _d 0 |
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F_ia (I,J) = 0.0 _d 0 |
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F_io_net (I,J) = 0.0 _d 0 |
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F_ia_net (I,J) = 0.0 _d 0 |
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F_swi (I,J) = 0.0 _d 0 |
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F_lwd (I,J) = 0.0 _d 0 |
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F_lwu (I,J) = 0.0 _d 0 |
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F_lh (I,J) = 0.0 _d 0 |
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F_sens (I,J) = 0.0 _d 0 |
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c set the surface temperature to zero if there is no ice there. |
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IF (HICE_ACTUAL(I,J) .NE. 0.0) THEN |
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tsurfLoc (I,J) = MIN(TMELT, TSURF(I,J,bi,bj)) |
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ELSE |
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tsurfLoc(I,J) = TMELT |
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ENDIF |
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TSURF(I,J,bi,bj) = tsurfLoc(I,J) |
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atempLoc (I,J) = MAX(TMELT + MIN_ATEMP,ATEMP(I,J,bi,bj)) |
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lwdownLoc(I,J) = LWDOWN(I,J,bi,bj) |
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ENDDO |
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ENDDO |
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C COME HERE AT START OF ITERATION |
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DO J=1,sNy |
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DO I=1,sNx |
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IF (HICE_ACTUAL(I,J) .NE. 0.0) THEN |
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C DECIDE ON ALBEDO |
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IF (tsurfLoc(I,J) .GE. TMELT) THEN |
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IF (HSNOW_ACTUAL(I,J) .EQ. 0.0) THEN |
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ALB(I,J) = SEAICE_wetIceAlb |
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ELSE ! some snow |
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ALB(I,J) = SEAICE_wetSnowAlb |
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ENDIF |
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ELSE ! no surface melting |
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IF (HSNOW_ACTUAL(I,J) .EQ. 0.0) THEN |
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ALB(I,J) = SEAICE_dryIceAlb |
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ELSE ! some snow |
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ALB(I,J) = SEAICE_drySnowAlb |
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ENDIF |
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ENDIF |
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F_lwd(I,J) = - 0.97 _d 0 * lwdownLoc(I,J) |
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IF (HSNOW_ACTUAL(I,J) .GT. 0.0) THEN |
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IcePenetratingShortwaveFluxFraction(I,J) = ZERO |
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ELSE |
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IcePenetratingShortwaveFluxFraction(I,J) = |
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& XIO*EXP(-1.5 _d 0 * HICE_ACTUAL(I,J)) |
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ENDIF |
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AbsorbedShortwaveFlux(I,J) = -(ONE - ALB(I,J))* |
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& (1.0 - IcePenetratingShortwaveFluxFraction(I,J)) |
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& *SWDOWN(I,J,bi,bj) |
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IcePenetratingShortwaveFlux(I,J) = -(ONE - ALB(I,J))* |
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& IcePenetratingShortwaveFluxFraction(I,J) |
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& *SWDOWN(I,J,bi,bj) |
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F_swi(I,J) = AbsorbedShortwaveFlux(I,J) |
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c set a min ice as 5 cm to limit arbitrarily large conduction. |
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HICE_ACTUAL(I,J) = max(HICE_ACTUAL(I,J),0.05) |
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effConduct = XKI * XKS / |
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& (XKS * HICE_ACTUAL(I,J) + XKI * HSNOW_ACTUAL(I,J)) |
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DO ITER=1,IMAX_TICE |
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t1 = tsurfLoc(I,J) |
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t2 = t1*t1 |
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t3 = t2*t1 |
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t4 = t2*t2 |
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tsurfLocOld = t1 |
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c log 10 of the sat vap pressure |
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mm_log10pi = -aa1 / t1 + aa2 |
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c saturation vapor pressure |
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mm_pi = 10**(mm_log10pi) |
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c over ice specific humidity |
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qhice_mm(I,J) = bb1*mm_pi / (Ppascals - (1.0 - bb1) * mm_pi) |
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c constant for sat vap pressure derivative w.r.t tice |
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cc3t = 10**(aa1 / t1) |
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c the actual derivative |
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dqhice_dTice = cc1 * cc3t /( (cc2-cc3t*Ppascals)**2 * t2) |
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c the full derivative |
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dFiDTs1 = 4.0 * D3*t3 + effConduct + D1*UG(I,J) + |
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& D1I*UG(I,J)*dqhice_dTice |
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F_lh(I,J) = D1I * UG(I,J) * (qhice_mm(I,J)-AQH(I,J,bi,bj)) |
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F_c(I,J) = -effConduct * (TB - t1) |
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F_lwu(I,J) = t4 * D3 |
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F_sens(I,J) = D1 * UG(I,J) * (t1 - atempLoc(I,J)) |
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F_ia(I,J) = F_lwd(I,J) + F_swi(I,J) + F_lwu(I,J) + |
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& F_c(I,J) + F_sens(I,J) + F_lh(I,J) |
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tsurfLoc(I,J) = tsurfLoc(I,J) - F_ia(I,J) / dFiDTs1 |
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#ifdef SEAICE_DEBUG |
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print *,'ice-iter tsurfLc,|dif|', I,J, ITER,tsurfLoc(I,J), |
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& log10(abs(tsurfLoc(I,J) - tsurfLocOld)) |
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#endif |
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ENDDO !/* Iterations */ |
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tsurfLoc(I,J) = MIN(tsurfLoc(I,J),TMELT) |
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TSURF(I,J,bi,bj) = tsurfLoc(I,J) |
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t1 = tsurfLoc(I,J) |
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t2 = t1*t1 |
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t3 = t2*t1 |
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t4 = t2*t2 |
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c log 10 of the sat vap pressure |
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mm_log10pi = -aa1 / t1 + aa2 |
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c saturation vapor pressure |
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mm_pi = 10**(mm_log10pi) |
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c over ice specific humidity |
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qhice_mm(I,J) = bb1*mm_pi / (Ppascals - (1.0 - bb1) * mm_pi) |
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F_lh(I,J) = D1I * UG(I,J) * (qhice_mm(I,J)-AQH(I,J,bi,bj)) |
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F_c(I,J) = -effConduct * (TB - t1) |
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F_lwu(I,J) = t4 * D3 |
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F_sens(I,J) = D1 * UG(I,J) * (t1 - atempLoc(I,J)) |
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c exlude conductive flux, the actual flux with the atmosphere. |
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F_ia(I,J) = F_lwd(I,J) + F_swi(I,J) + F_lwu(I,J) + |
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& F_sens(I,J) + F_lh(I,J) |
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IF (F_c(I,J) .LT. 0.0) THEN |
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F_io_net(I,J) = -F_c(I,J) |
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F_ia_net(I,J) = 0.0 |
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ELSE |
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F_io_net(I,J) = 0.0 |
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F_ia_net(I,J) = F_lwd(I,J) + F_swi(I,J) + F_lwu(I,J) + |
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& F_sens(I,J) + F_lh(I,J) |
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ENDIF !/* conductive fluxes up or down */ |
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#ifdef SEAICE_DEBUG |
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print '(A,2i4,3(1x,1P2E15.3))', |
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& 'ibi i j T(SURF, surfLoc,atmos)',I,J, |
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& TSURF(I,J,bi,bj), tsurfLoc(I,J),atempLoc(I,J) |
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print '(A,2i4,3(1x,1P2E15.3))', |
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& 'ibi i j QSW(Tot, Abs, Pen) ',I,J, |
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& SWDOWN(I,J,bi,bj), AbsorbedShortwaveFlux(I,J), |
| 282 |
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& IcePenetratingShortwaveFlux(I,J) |
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print '(A,2i4,3(1x,1P2E15.3))', |
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& 'ibi i j IcePenSWFluxFrac, Alb ',I,J, |
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^ IcePenetratingShortwaveFluxFraction(I,J), ALB(I,J) |
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print '(A,2i4,3(1x,1P2E15.3))', |
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& 'ibi i j qh(ATM ICE) ',I,J, |
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& AQH(I,J,bi,bj),qhice_mm(I,J) |
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print '(A,2i4,3(1x,1P2E15.3))', |
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& 'ibi i j F(lwd,swi,lwu) ',I,J, |
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& F_lwd(I,J), F_swi(I,J), F_lwu(I,J) |
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print '(A,2i4,3(1x,1P2E15.3))', |
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& 'ibi i j F(c,lh,sens) ',I,J, |
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& F_c(I,J), F_lh(I,J), F_sens(I,J) |
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| 300 |
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print '(A,2i4,3(1x,1P2E15.3))', |
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& 'ibi i j F(io_net,ia_net,ia) ',I,J, |
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& F_io_net(I,J), F_ia_net(I,J), F_ia(I,J) |
| 303 |
|
|
#endif |
| 304 |
|
|
|
| 305 |
|
|
ENDIF !/* HICE_ACTUAL > 0 */ |
| 306 |
|
|
|
| 307 |
|
|
ENDDO !/* i */ |
| 308 |
|
|
ENDDO !/* j */ |
| 309 |
|
|
|
| 310 |
|
|
RETURN |
| 311 |
|
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END |
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