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C $Header: /u/gcmpack/MITgcm/pkg/thsice/thsice_get_exf.F,v 1.2 2006/06/06 18:52:13 mlosch Exp $ |
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C $Name: $ |
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|
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#include "THSICE_OPTIONS.h" |
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#ifdef ALLOW_EXF |
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#include "EXF_OPTIONS.h" |
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#endif |
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|
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CBOP |
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C !ROUTINE: THSICE_GET_EXF |
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C !INTERFACE: |
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SUBROUTINE THSICE_GET_EXF( |
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I iceornot, tsfCel, |
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O flxExceptSw, df0dT, evapLoc, dEvdT, |
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I i,j,bi,bj,myThid ) |
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C !DESCRIPTION: \bv |
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C *==========================================================* |
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C | S/R THSICE_GET_EXF |
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C *==========================================================* |
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C | Interface S/R : get Surface Fluxes from pkg EXF |
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C *==========================================================* |
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C \ev |
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|
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C !USES: |
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IMPLICIT NONE |
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|
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C == Global data == |
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#ifdef ALLOW_EXF |
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# include "SIZE.h" |
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# include "EEPARAMS.h" |
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# include "PARAMS.h" |
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# include "exf_constants.h" |
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# include "exf_param.h" |
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# include "exf_fields.h" |
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#endif |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C === Routine arguments === |
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C iceornot :: 0=open water, 1=ice cover |
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C tsfCel :: surface (ice or snow) temperature (oC) |
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C flxExceptSw :: net (downward) surface heat flux, except short-wave [W/m2] |
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C df0dT :: deriv of flx with respect to Tsf [W/m/K] |
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C evapLoc :: surface evaporation (>0 if evaporate) [kg/m2/s] |
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C dEvdT :: deriv of evap. with respect to Tsf [kg/m2/s/K] |
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C i,j, bi,bj :: current grid point indices |
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C myThid :: Thread no. that called this routine. |
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INTEGER i,j, bi,bj |
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INTEGER myThid |
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INTEGER iceornot |
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_RL tsfCel |
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_RL flxExceptSw |
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_RL df0dT |
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_RL evapLoc |
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_RL dEvdT |
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CEOP |
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|
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#ifdef ALLOW_THSICE |
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#ifdef ALLOW_EXF |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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C === Local variables === |
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|
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_RL aln |
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|
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integer iter |
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_RL delq |
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_RL deltap |
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_RL hqol |
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_RL htol |
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_RL huol |
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_RL psimh |
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_RL psixh |
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_RL qstar |
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_RL rd |
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_RL re |
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_RL rdn |
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_RL rh |
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_RL ssq |
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_RL stable |
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_RL tstar |
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_RL t0 |
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_RL ustar |
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_RL uzn |
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_RL shn |
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_RL xsq |
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_RL x |
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_RL tau |
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_RL tmpbulk |
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|
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C additional variables that are copied from bulkf_formula_lay: |
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C upward LW at surface (W m-2) |
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_RL flwup |
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C net (downward) LW at surface (W m-2) |
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_RL flwNet_dwn |
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C gradients of latent/sensible net upward heat flux |
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C w/ respect to temperature |
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_RL dflhdT, dfshdT, dflwupdT |
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C emissivities, called emittance in exf |
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_RL emiss |
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C Tsf :: surface temperature [K] |
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C Ts2 :: surface temperature square [K^2] |
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_RL Tsf |
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_RL Ts2 |
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C latent heat of evaporation or sublimation [J/kg] |
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_RL lath |
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|
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C == external functions == |
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|
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c _RL exf_BulkqSat |
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c external exf_BulkqSat |
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_RL exf_BulkCdn |
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external exf_BulkCdn |
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_RL exf_BulkRhn |
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external exf_BulkRhn |
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|
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C == end of interface == |
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|
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C copy a few variables to names used in bulkf_formula_lay |
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Tsf = tsfCel+cen2kel |
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Ts2 = Tsf*Tsf |
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IF ( iceornot.EQ.0 ) THEN |
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lath = flamb |
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dEvdT = cvapor_exp |
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ELSE |
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lath = flamb+flami |
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dEvdT = cvapor_exp_ice |
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ENDIF |
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|
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Cph This statement cannot be a PARAMETER statement in the header, |
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Cph but must come here; it is not fortran77 standard |
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aln = log(ht/zref) |
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|
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C-- Use atmospheric state to compute surface fluxes. |
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|
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C-- Compute the turbulent surface fluxes. |
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|
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C Initial guess: z/l=0.0; hu=ht=hq=z |
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C Iterations: converge on z/l and hence the fluxes. |
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C t0 : virtual temperature (K) |
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C ssq : sea surface humidity (kg/kg) |
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C deltap : potential temperature diff (K) |
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|
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if ( atemp(i,j,bi,bj) .ne. 0. _d 0 ) then |
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t0 = atemp(i,j,bi,bj)* |
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& (exf_one + humid_fac*aqh(i,j,bi,bj)) |
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c tmpbulk= exf_BulkqSat(Tsf) |
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c ssq = saltsat*tmpbulk/atmrho |
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tmpbulk = cvapor_fac_ice/exp(cvapor_exp_ice/Tsf) |
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ssq = tmpbulk/atmrho |
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deltap = atemp(i,j,bi,bj) + gamma_blk*ht - Tsf |
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delq = aqh(i,j,bi,bj) - ssq |
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stable = exf_half + sign(exf_half, deltap) |
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tmpbulk= exf_BulkCdn(sh(i,j,bi,bj)) |
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rdn = sqrt(tmpbulk) |
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ustar = rdn*sh(i,j,bi,bj) |
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tmpbulk= exf_BulkRhn(stable) |
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tstar = tmpbulk*deltap |
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qstar = cdalton*delq |
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|
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do iter = 1,niter_bulk |
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|
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huol = czol*(tstar/t0 + |
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& qstar/(exf_one/humid_fac+aqh(i,j,bi,bj)))/ |
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& ustar**2 |
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huol = max(huol,zolmin) |
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stable = exf_half + sign(exf_half, huol) |
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htol = huol*ht/hu |
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hqol = huol*hq/hu |
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|
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C Evaluate all stability functions assuming hq = ht. |
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xsq = max(sqrt(abs(exf_one - 16.*huol)),exf_one) |
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x = sqrt(xsq) |
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psimh = -psim_fac*huol*stable + |
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& (exf_one - stable)* |
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& (log((exf_one + x*(exf_two + x))* |
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& (exf_one + xsq)/8.) - exf_two*atan(x) + |
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& pi*exf_half) |
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xsq = max(sqrt(abs(exf_one - 16.*htol)),exf_one) |
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psixh = -psim_fac*htol*stable + (exf_one - stable)* |
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& exf_two*log((exf_one + xsq)/exf_two) |
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|
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C Shift wind speed using old coefficient |
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ccc rd = rdn/(exf_one + rdn/karman* |
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ccc & (log(hu/zref) - psimh) ) |
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rd = rdn/(exf_one - rdn/karman*psimh ) |
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shn = sh(i,j,bi,bj)*rd/rdn |
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uzn = max(shn, umin) |
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|
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C Update the transfer coefficients at 10 meters |
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C and neutral stability. |
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|
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tmpbulk= exf_BulkCdn(uzn) |
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rdn = sqrt(tmpbulk) |
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|
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C Shift all coefficients to the measurement height |
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C and stability. |
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c rd = rdn/(exf_one + rdn/karman*(log(hu/zref) - psimh)) |
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rd = rdn/(exf_one - rdn/karman*psimh) |
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tmpbulk= exf_BulkRhn(stable) |
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rh = tmpbulk/( exf_one + |
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& tmpbulk/karman*(aln - psixh) ) |
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re = cdalton/( exf_one + |
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& cdalton/karman*(aln - psixh) ) |
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|
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C Update ustar, tstar, qstar using updated, shifted |
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C coefficients. |
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ustar = rd*sh(i,j,bi,bj) |
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qstar = re*delq |
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tstar = rh*deltap |
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enddo |
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|
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tau = atmrho*ustar**2 |
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tau = tau*us(i,j,bi,bj)/sh(i,j,bi,bj) |
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|
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evapLoc = -tau*qstar/ustar |
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hl(i,j,bi,bj) = -lath*evapLoc |
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hs(i,j,bi,bj) = atmcp*tau*tstar/ustar |
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#ifndef EXF_READ_EVAP |
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cdm evap(i,j,bi,bj) = tau*qstar/ustar |
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cdm !!! need to change sign and to convert from kg/m^2/s to m/s !!! |
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evap(i,j,bi,bj) = -recip_rhonil*evapLoc |
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#endif |
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|
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C--- surf.Temp derivative of turbulent Fluxes |
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dEvdT = (tau*re/ustar)*ssq*dEvdT/Ts2 |
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dflhdT = -lath*dEvdT |
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dfshdT = -atmcp*tau*rh/ustar |
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|
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C--- Upward long wave radiation |
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IF ( iceornot.EQ.0 ) THEN |
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emiss = ocean_emissivity |
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ELSEIF (iceornot.EQ.2) THEN |
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emiss = snow_emissivity |
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ELSE |
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emiss = ice_emissivity |
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ENDIF |
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flwup = emiss*stefanBoltzmann*Ts2*Ts2 |
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dflwupdT = emiss*stefanBoltzmann*Ts2*Tsf * 4. _d 0 |
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|
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C-- Total derivative with respect to surface temperature |
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df0dT = -dflwupdT+dfshdT+dflhdT |
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|
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flwNet_dwn = lwdown(i,j,bi,bj) - flwup |
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flxExceptSw = flwNet_dwn + hs(i,j,bi,bj) + hl(i,j,bi,bj) |
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|
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endif |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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|
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#endif /* ALLOW_EXF */ |
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#endif /* ALLOW_THSICE */ |
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|
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RETURN |
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END |
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