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C $Header: /u/gcmpack/MITgcm/pkg/bulk_force/bulkf_formula_vince.F,v 1.2 2003/10/09 04:19:19 edhill Exp $ |
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C $Name: $ |
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c swd -- bulkf formula used in bulkf and ice pkgs |
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c cswd -- adapted from vince/andrei surf_flux.f |
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|
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#include "BULK_FORCE_OPTIONS.h" |
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subroutine bulkf_formula_vince( |
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I uw, vw, us, Ta, Qa, nc, tsf_in, |
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I UFocean, flwup, flha, fsha, df0dT, |
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I ust, vst, evp, ssq, |
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I iceornot, readstress |
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& ) |
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|
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IMPLICIT NONE |
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c |
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#include "EEPARAMS.h" |
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#include "SIZE.h" |
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#include "PARAMS.h" |
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#include "DYNVARS.h" |
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#include "GRID.h" |
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#include "FFIELDS.h" |
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#ifdef ALLOW_BULKFORMULA |
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#include "BULKF_ICE_CONSTANTS.h" |
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#endif |
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#ifdef ALLOW_TSEAICE |
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#include "ICE.h" |
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#endif |
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|
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c |
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c calculate bulk formula fluxes over open ocean or seaice |
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c |
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c input |
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_RL us ! wind speed |
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_RL uw ! zonal wind speed (at grid center) |
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_RL vw ! meridional wind speed (at grid center) |
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_RL Ta ! air temperature at ht |
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_RL Qa ! specific humidity at ht |
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_RL nc ! cloud cover |
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_RL tsf_in ! surface temperature (either ice or open water) |
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integer iceornot ! 0=open water, 1=ice cover |
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logical readstress |
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c output |
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_RL flwup ! upward long wave radiation |
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_RL flha ! latent heat flux |
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_RL fsha ! sensible heat flux |
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_RL df0dT ! derivative of heat flux with respect to Tsf |
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_RL ust ! zonal wind stress (at grid center) |
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_RL vst ! meridional wind stress (at grid center) |
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_RL evp ! evaporation rate (over open water) |
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_RL ssq ! surface specific humidity (kg/kg) |
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c |
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c input and output |
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_RL UFocean |
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c |
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c local variables |
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_RL ea |
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_RL mixratio |
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_RL stable |
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_RL tsf ! surface temperature in K |
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_RL ht ! reference height (m) |
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_RL usm ! wind speed limited |
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_RL deltap ! potential temperature diff (K) |
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_RL delq ! specific humidity difference |
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_RL lhcoef |
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_RL shcoef |
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_RL dflhdT ! derivative of latent heat with respect to T |
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_RL dfshdT ! derivative of sensible heat with respect to T |
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_RL dflwupdT ! derivative of long wave with respect to T |
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c from vinces |
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_RL elhx |
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_RL rough |
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_RL cdn |
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_RL surf_emissivity ! ocean or ice emissivity |
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_RL qg |
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_RL rigs |
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_RL dm |
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_RL dh |
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_RL cdm |
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_RL cdh |
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_RL rcdhws |
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_RL Tsv |
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_RL dqssdt |
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_RL x |
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integer lr |
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|
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_RL flwdown ! part of output eventually QQ |
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#ifdef ALLOW_BULKFORMULA |
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|
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_RL AROUGH(20),BROUGH(20),CROUGH(20),DROUGH(20),EROUGH(20) |
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DATA AROUGH/16.59,13.99,10.4,7.35,5.241,3.926,3.126,2.632,2.319, |
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*2.116,1.982,1.893,1.832,1.788,1.757,1.733,1.714,1.699,1.687,1.677/ |
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DATA BROUGH/3.245,1.733,0.8481,0.3899,0.1832,0.9026E-1,0.4622E-1, |
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* .241E-1,.1254E-1,.6414E-2,.3199E-2,.1549E-2,.7275E-3,.3319E-3, |
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* .1474E-3,.6392E-4,.2713E-4,.1130E-4,.4630E-5,.1868E-5/ |
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DATA CROUGH/5.111,3.088,1.682,.9239,.5626,.3994,.3282,.3017,.299 |
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*,.3114,.3324,.3587,.3881,.4186,.4492,.4792,.5082,.5361,.5627, |
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* .5882/ |
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DATA DROUGH/1.24,1.02,0.806,0.682,0.661,0.771,0.797,0.895,0.994, |
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* 1.09,1.18,1.27,1.35,1.43,1.50,1.58,1.65,1.71,1.78,1.84/ |
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DATA EROUGH/0.128,0.130,0.141,0.174,0.238,0.330,0.438,0.550,0.660, |
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* 0.766,0.866,0.962,1.05,1.14,1.22,1.30,1.37,1.45,1.52,1.58/ |
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|
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|
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c --- external functions --- |
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_RL exf_BulkCdn |
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external exf_BulkCdn |
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|
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c UFocean=1e-2 !QQ what is this and what is the number? |
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|
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c -- set all to zero |
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flwup = 0.d0 ! upward long wave radiation |
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flha = 0.d0 ! latent heat flux |
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fsha = 0.d0 ! sensible heat flux |
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df0dT = 0.d0 ! derivative of heat flux with respect to Tsf |
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ust = 0.d0 ! zonal wind stress (at grid center) |
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vst = 0.d0 ! meridional wind stress (at grid center) |
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evp = 0.d0 ! evaporation rate (over open water) |
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ssq = 0.d0 ! surface specific humidity (kg/kg) |
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|
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|
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Qa=max(Qa,1e-7) |
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Tsf=Tsf_in+Tf0kel |
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ht=10.e0 |
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c Wind speed |
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if (us.eq.0.d0) then !in case we have a constant prescribed us |
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us = sqrt(uw*uw + vw*vw) |
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endif |
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usm = max(us,1.d-5) |
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cQQQ try to limit drag |
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cQQQ usm = min(usm,5.d0) |
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|
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c from vinces surfflux.F |
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if (iceornot.eq.0) then |
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c for open water |
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rough=max(0.018*UFocean/gravity,0.5E-5) !QQcheck |
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elhx=Lvap !QQcheck |
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else |
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c for sea ice cover |
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rough=10**(-3.37) !QQcheck |
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elhx = Lvap_ice |
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endif |
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Qg =3.797915*exp(elhx*(7.93252e-6-2.166847E-3/Ta))/p0 |
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c |
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c find stability of atmospheric surface layer stratification |
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rough=log10(ht/rough) |
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cdn=.0231/(rough*rough) !QQcheck |
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lr=rough*2.d0 - 5.d-1 !QQcheck |
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lr=max(1,min(lr,20)) |
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rigs=ht*gravity*(Tsf-Ta)/(Ta*usm*usm) |
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if (rigs.le.0.d0) then |
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c unstable |
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dm=sqrt((1.d0-AROUGH(lr)*rigs)*(1.d0-BROUGH(lr)*rigs)/ |
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& (1.d0-CROUGH(lr)*rigs)) |
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dh=1.35*sqrt((1.d0-DROUGH(lr)*rigs)/ |
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& (1.d0-EROUGH(lr)*rigs)) !QQcheck |
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else |
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c stable |
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dm=1.d0/(1.d0+(11.238+89.9*rigs)*rigs) !QQcheck |
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dh=1.35/(1.d0+1.93*rigs) !QQcheck |
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endif |
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cdm = cdn * dm |
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cdh = cdn * dm * dh |
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|
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rcdhws = cdh*us*100*p0/(Rgas*Tsf) !QQ check units (take out 100) |
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ssq =3.797915*exp(elhx*(7.93252e-6-2.166847E-3/Tsf))/p0 |
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cBB debugging |
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cBB print*,'ssq', qcoef, ssq |
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c |
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|
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if (Qa.le.ssq) then |
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Tsv=Tsf |
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ssq=ssq !QQQQ should be ssq=qa? |
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else |
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dqssdt=ssq*elhx/(Rvap*Tsf*Tsf) |
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x=(Qa-ssq)/(dqssdt+(sha/elhx)) |
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Tsv=Tsf+x |
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ssq=Qa+x*(sha/elhx) |
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endif |
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|
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deltap = Ta - Tsv !tsv-Ta |
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delq = Qg - ssq !Qsv - Qg |
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cmine deltap = ta - tsf + gamma_blk*ht |
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cmine delq = Qa - ssq |
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c latent heat |
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c ------------- |
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cvinc lhcoef = Lvap*rcdhws |
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cmine latent heat coeff. following Gill 2.4.6 and 2.6.2 formula |
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lhcoef =Lvap*rhoa*us*5e-3 !QQ name coeff. !QQwas 1.5e-3 |
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flha = lhcoef*delq !QQQ |
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evp = lhcoef*delq/Lvap/rhosw |
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c sensible heat |
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c ---------------- |
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cvinc shcoef=sha*rcdhws |
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cmine sensible heat coeff. following Gill 2.4.5 formula |
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stable = 5.d-1 + sign(5.d-1, deltap) |
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if (stable.gt.0) then |
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shcoef = 0.83e-3*rhoa*us*cpair |
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else |
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shcoef = 1.10e-3*rhoa*us*cpair |
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endif |
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fsha = shcoef*deltap |
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|
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c long wave |
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c ------------ |
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cvinc if (iceornot.eq.1) then |
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cvinc#ifdef ALLOW_TSEAICE |
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cvinc if (snowheight.gt.0.d0) then |
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cvinc surf_emissivity=snow_emissivity |
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cvinc else |
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cvinc surf_emissivity=ice_emissivity |
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cvinc endif |
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cvinc#endif |
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cvinc else |
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cvinc surf_emissivity=ocean_emissivity |
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cvinc endif |
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cvinc flwup = -surf_emissivity*stefan* |
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cvinc & Tsf**4.0 !QQcheck |
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cvinc flwdown = atm_emissivity*stefan * |
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cvinc & Ta**4.0 * (1.0+0.275*nc) * |
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cvinc & (1.0-0.261*exp(-7.77e-4*(273.15-Ta)**2.0)) !QQcheck |
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cvinc flwup=flwup+flwdown !QQQQQ?? |
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cmine up (net) long wave radiation |
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mixratio=Qa/(1-Qa) |
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ea=p0*mixratio/(0.62197+mixratio) |
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flwup=-0.985*stefan*tsf**4 |
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& *(0.39-0.05*sqrt(ea)) |
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& *(1-0.6*nc**2) |
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c ------------------------- |
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UFocean=cdm*us*us |
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|
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#ifdef ALLOW_TSEAICE |
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if (iceornot.eq.1) then |
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c derivatives of heat flux |
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c ------------------------- |
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c dflwupdT=-4.0*surf_emissivity*stefan * |
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c & Tsf**3.0 !QQcheck |
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cQQ corrected for Vince formula |
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dflhdT = -lhcoef*ssq*Lvap*2.166847E-3/(Tsf**2) |
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dfshdT = -shcoef !QQQQQQ not quite right |
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cmine derivatives with respect to Tsf |
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cmine dflhdT = -lhcoef*Tf0kel*ssq*22.47/(tsf**2) |
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cmine dfshdT = -shcoef |
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dflwupdT=-4.*0.985*stefan*tsf**3 |
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& *(0.39-0.05*sqrt(ea)) |
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c |
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c total derivative with respect to surface temperature |
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df0dT=dflwupdT+dfshdT+dflhdT |
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cBB |
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cBB print*,'derivatives:',df0dT,dflwupdT,dfshdT,dflhdT |
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endif |
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#endif /*ALLOW_TSEAICE*/ |
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c |
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c wind stress at center points |
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c ----------------------------- |
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if (.NOT.readstress) then |
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ust = rhoa*exf_BulkCdn(usm)*us*uw |
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vst = rhoa*exf_BulkCdn(usm)*us*vw |
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endif |
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#endif /*ALLOW_BULKFORMULA*/ |
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|
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return |
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end |
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