C $Header: /u/gcmpack/MITgcm/pkg/dic/dic_surfforcing.F,v 1.30 2015/01/11 20:02:41 jmc Exp $ C $Name: $ #include "DIC_OPTIONS.h" #include "PTRACERS_OPTIONS.h" CBOP C !ROUTINE: DIC_SURFFORCING C !INTERFACE: ========================================================== SUBROUTINE DIC_SURFFORCING( PTR_CO2 , PTR_ALK, PTR_PO4, GDC, I bi,bj,iMin,iMax,jMin,jMax, I myIter,myTime,myThid) C !DESCRIPTION: C Calculate the carbon air-sea flux terms C following external_forcing_dic.F (OCMIP run) from Mick C !USES: =============================================================== IMPLICIT NONE #include "SIZE.h" #include "DYNVARS.h" #include "EEPARAMS.h" #include "PARAMS.h" #include "GRID.h" #include "FFIELDS.h" #include "DIC_VARS.h" C !INPUT PARAMETERS: =================================================== C myThid :: thread number C myIter :: current timestep C myTime :: current time c PTR_CO2 :: DIC tracer field INTEGER myIter, myThid _RL myTime _RL PTR_CO2(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr) _RL PTR_ALK(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr) _RL PTR_PO4(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr) INTEGER iMin,iMax,jMin,jMax, bi, bj C !OUTPUT PARAMETERS: =================================================== c GDC :: tendency due to air-sea exchange _RL GDC(1-OLx:sNx+OLx,1-OLy:sNy+OLy) #ifdef ALLOW_PTRACERS C !LOCAL VARIABLES: ==================================================== INTEGER i,j, kLev _RL co3dummy C Number of iterations for pCO2 solvers... C Solubility relation coefficients _RL SchmidtNoDIC(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL pCO2sat(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL Kwexch(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL pisvel(1-OLx:sNx+OLx,1-OLy:sNy+OLy) C local variables for carbon chem _RL surfalk(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL surfphos(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL surfsi(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL surftemp(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL surfsalt(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL surfdic(1-OLx:sNx+OLx,1-OLy:sNy+OLy) #ifdef ALLOW_OLD_VIRTUALFLUX _RL VirtualFlux(1-OLx:sNx+OLx,1-OLy:sNy+OLy) #endif CEOP cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc kLev=1 cc if coupled to atmsopheric model, use the cc Co2 value passed from the coupler c#ifndef USE_ATMOSCO2 cC PRE-INDUSTRIAL STEADY STATE pCO2 = 278.0 ppmv c DO j=1-OLy,sNy+OLy c DO i=1-OLx,sNx+OLx c AtmospCO2(i,j,bi,bj)=278.0 _d -6 c ENDDO c ENDDO c#endif C ================================================================= C determine inorganic carbon chem coefficients DO j=jMin,jMax DO i=iMin,iMax #ifdef DIC_BIOTIC cQQQQ check ptracer numbers #ifdef DIC_BOUNDS surfalk(i,j) = max(0.4 _d 0, & min(10. _d 0,PTR_ALK(i,j,klev))) & * maskC(i,j,kLev,bi,bj) surfphos(i,j) = max(1.0 _d -11, & min(1. _d -1,PTR_PO4(i,j,klev))) & * maskC(i,j,kLev,bi,bj) #else surfalk(i,j) = PTR_ALK(i,j,klev) & * maskC(i,j,kLev,bi,bj) surfphos(i,j) = PTR_PO4(i,j,klev) & * maskC(i,j,kLev,bi,bj) #endif #else surfalk(i,j) = 2.366595 _d 0 * salt(i,j,kLev,bi,bj)/gsm_s & * maskC(i,j,kLev,bi,bj) surfphos(i,j) = 5.1225 _d -4 * maskC(i,j,kLev,bi,bj) #endif C FOR NON-INTERACTIVE Si surfsi(i,j) = SILICA(i,j,bi,bj) * maskC(i,j,kLev,bi,bj) #ifdef DIC_BOUNDS surftemp(i,j) = max(-4. _d 0, & min(50. _d 0, theta(i,j,kLev,bi,bj))) surfsalt(i,j) = max(4. _d 0, & min(50. _d 0, salt(i,j,kLev,bi,bj))) surfdic(i,j) = max(0.4 _d 0, & min(10. _d 0, PTR_CO2(i,j,kLev))) #else surftemp(i,j) = theta(i,j,kLev,bi,bj) surfsalt(i,j) = salt(i,j,kLev,bi,bj) surfdic(i,j) = PTR_CO2(i,j,kLev) #endif ENDDO ENDDO CALL CARBON_COEFFS( I surftemp,surfsalt, I bi,bj,iMin,iMax,jMin,jMax,myThid) C==================================================================== DO j=jMin,jMax DO i=iMin,iMax C Compute AtmosP and Kwexch_Pre which are re-used for flux of O2 #ifdef USE_PLOAD C Convert anomalous pressure pLoad (in Pa) from atmospheric model C to total pressure (in Atm) C Note: it is assumed the reference atmospheric pressure is 1Atm=1013mb C rather than the actual ref. pressure from Atm. model so that on C average AtmosP is about 1 Atm. AtmosP(i,j,bi,bj)= 1. _d 0 + pLoad(i,j,bi,bj)/Pa2Atm #endif C Pre-compute part of exchange coefficient: pisvel*(1-fice) C Schmidt number is accounted for later pisvel(i,j)=0.337 _d 0 *wind(i,j,bi,bj)**2/3.6 _d 5 Kwexch_Pre(i,j,bi,bj) = pisvel(i,j) & * (1. _d 0 - FIce(i,j,bi,bj)) ENDDO ENDDO c pCO2 solver... C$TAF LOOP = parallel DO j=jMin,jMax C$TAF LOOP = parallel DO i=iMin,iMax IF ( maskC(i,j,kLev,bi,bj).NE.0. _d 0 ) THEN CALL CALC_PCO2_APPROX( I surftemp(i,j),surfsalt(i,j), I surfdic(i,j), surfphos(i,j), I surfsi(i,j),surfalk(i,j), I ak1(i,j,bi,bj),ak2(i,j,bi,bj), I ak1p(i,j,bi,bj),ak2p(i,j,bi,bj),ak3p(i,j,bi,bj), I aks(i,j,bi,bj),akb(i,j,bi,bj),akw(i,j,bi,bj), I aksi(i,j,bi,bj),akf(i,j,bi,bj), I ak0(i,j,bi,bj), fugf(i,j,bi,bj), I ff(i,j,bi,bj), I bt(i,j,bi,bj),st(i,j,bi,bj),ft(i,j,bi,bj), U pH(i,j,bi,bj),pCO2(i,j,bi,bj),co3dummy, I i,j,kLev,bi,bj,myIter,myThid ) ELSE pCO2(i,j,bi,bj)=0. _d 0 ENDIF ENDDO ENDDO DO j=jMin,jMax DO i=iMin,iMax IF ( maskC(i,j,kLev,bi,bj).NE.0. _d 0 ) THEN C calculate SCHMIDT NO. for CO2 SchmidtNoDIC(i,j) = & sca1 & + sca2 * theta(i,j,kLev,bi,bj) & + sca3 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj) & + sca4 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj) & *theta(i,j,kLev,bi,bj) c make sure Schmidt number is not negative (will happen if temp>39C) SchmidtNoDIC(i,j)=max(1.0 _d -2, SchmidtNoDIC(i,j)) C Determine surface flux (FDIC) C first correct pCO2at for surface atmos pressure pCO2sat(i,j) = & AtmosP(i,j,bi,bj)*AtmospCO2(i,j,bi,bj) C then account for Schmidt number Kwexch(i,j) = Kwexch_Pre(i,j,bi,bj) & / sqrt(SchmidtNoDIC(i,j)/660.0 _d 0) #ifdef WATERVAP_BUG C Calculate flux in terms of DIC units using K0, solubility C Flux = Vp * ([CO2sat] - [CO2]) C CO2sat = K0*pCO2atmos*P/P0 C Converting pCO2 to [CO2] using ff, as in CALC_PCO2 FluxCO2(i,j,bi,bj) = & Kwexch(i,j)*( & ak0(i,j,bi,bj)*pCO2sat(i,j) - & ff(i,j,bi,bj)*pCO2(i,j,bi,bj) & ) #else C Corrected by Val Bennington Nov 2010 per G.A. McKinley s finding C of error in application of water vapor correction c Flux = kw*rho*(ff*pCO2atm-k0*FugFac*pCO2ocean) FluxCO2(i,j,bi,bj) = & Kwexch(i,j)*( & ff(i,j,bi,bj)*pCO2sat(i,j) - & pCO2(i,j,bi,bj)*fugf(i,j,bi,bj) & *ak0(i,j,bi,bj) ) & #endif ELSE FluxCO2(i,j,bi,bj) = 0. _d 0 ENDIF C convert flux (mol kg-1 m s-1) to (mol m-2 s-1) FluxCO2(i,j,bi,bj) = FluxCO2(i,j,bi,bj)/permil #ifdef ALLOW_OLD_VIRTUALFLUX IF (maskC(i,j,kLev,bi,bj).NE.0. _d 0) THEN c calculate virtual flux c EminusPforV = dS/dt*(1/Sglob) C NOTE: Be very careful with signs here! C Positive EminusPforV => loss of water to atmos and increase C in salinity. Thus, also increase in other surface tracers C (i.e. positive virtual flux into surface layer) C ...so here, VirtualFLux = dC/dt! VirtualFlux(i,j)=gsm_DIC*surfaceForcingS(i,j,bi,bj)/gsm_s c OR c let virtual flux be zero c VirtualFlux(i,j)=0.d0 c ELSE VirtualFlux(i,j)=0. _d 0 ENDIF #endif /* ALLOW_OLD_VIRTUALFLUX */ ENDDO ENDDO C update tendency DO j=jMin,jMax DO i=iMin,iMax GDC(i,j)= recip_drF(kLev)*recip_hFacC(i,j,kLev,bi,bj) & *(FluxCO2(i,j,bi,bj) #ifdef ALLOW_OLD_VIRTUALFLUX & + VirtualFlux(i,j) #endif & ) ENDDO ENDDO #endif RETURN END