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C $Header: /u/u3/gcmpack/MITgcm/model/src/timestep.F,v 1.32.2.1 2003/10/08 02:39:25 adcroft Exp $ |
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C $Name: $ |
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|
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#include "CPP_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: TIMESTEP |
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C !INTERFACE: |
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SUBROUTINE TIMESTEP( bi, bj, iMin, iMax, jMin, jMax, k, |
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I dPhiHydX,dPhiHydY, phiSurfX, phiSurfY, |
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I myTime, myIter, myThid ) |
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C !DESCRIPTION: \bv |
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C *==========================================================* |
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C | S/R TIMESTEP |
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C | o Step model fields forward in time |
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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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C == Global variables == |
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#include "SIZE.h" |
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#include "DYNVARS.h" |
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#include "EEPARAMS.h" |
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#include "PARAMS.h" |
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#include "GRID.h" |
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#include "SURFACE.h" |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine Arguments == |
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C dPhiHydX,Y :: Gradient (X & Y directions) of Hydrostatic Potential |
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C phiSurfX :: gradient of Surface potential (Pressure/rho, ocean) |
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C phiSurfY :: or geopotential (atmos) in X and Y direction |
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INTEGER bi,bj,iMin,iMax,jMin,jMax |
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INTEGER k |
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_RL dPhiHydX(1-Olx:sNx+Olx,1-Oly:sNy+Oly) |
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_RL dPhiHydY(1-Olx:sNx+Olx,1-Oly:sNy+Oly) |
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_RL phiSurfX(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL phiSurfY(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL myTime |
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INTEGER myIter, myThid |
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|
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C !LOCAL VARIABLES: |
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C == Local variables == |
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LOGICAL momForcing_In_AB |
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INTEGER i,j |
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_RL ab15,ab05 |
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_RL phxFac,phyFac, psFac |
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_RL gUtmp(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL gVtmp(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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#ifdef INCLUDE_CD_CODE |
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_RL guCor(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL gvCor(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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#endif |
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CEOP |
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|
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C Adams-Bashforth timestepping weights |
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IF (myIter .EQ. 0) THEN |
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ab15=1.0 |
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ab05=0.0 |
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ELSE |
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ab15=1.5+abeps |
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ab05=-0.5-abeps |
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ENDIF |
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|
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C-- stagger time step: grad Phi_Hyp is not in gU,gV => add it in this S/R |
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IF (staggerTimeStep) THEN |
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phxFac = pfFacMom |
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phyFac = pfFacMom |
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ELSE |
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phxFac = 0. |
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phyFac = 0. |
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ENDIF |
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|
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C-- explicit part of the surface potential gradient is added in this S/R |
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psFac = pfFacMom*(1. _d 0 - implicSurfPress) |
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|
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C-- including or excluding momentum forcing from Adams-Bashforth: |
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momForcing_In_AB = forcing_In_AB |
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momForcing_In_AB = .TRUE. |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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|
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C- Initialize local arrays (not really necessary but safer) |
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DO j=1-Oly,sNy+Oly |
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DO i=1-Olx,sNx+Olx |
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gUtmp(i,j) = 0. _d 0 |
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gVtmp(i,j) = 0. _d 0 |
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#ifdef INCLUDE_CD_CODE |
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guCor(i,j) = 0. _d 0 |
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gvCor(i,j) = 0. _d 0 |
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#endif |
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ENDDO |
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ENDDO |
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|
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C-- Forcing term inside the Adams-Bashforth: |
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IF (momForcing .AND. momForcing_In_AB) THEN |
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CALL EXTERNAL_FORCING_U( |
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I iMin,iMax,jMin,jMax,bi,bj,k, |
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I myTime,myThid) |
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CALL EXTERNAL_FORCING_V( |
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I iMin,iMax,jMin,jMax,bi,bj,k, |
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I myTime,myThid) |
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ENDIF |
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|
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C- Compute effective gU,gV_[n+1/2] terms (including Adams-Bashforth weights) |
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C and save gU,gV_[n] into guNm1,gvNm1 for the next time step. |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gUtmp(i,j) = ab15*gU(i,j,k,bi,bj) |
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& + ab05*guNm1(i,j,k,bi,bj) |
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gVtmp(i,j) = ab15*gV(i,j,k,bi,bj) |
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& + ab05*gvNm1(i,j,k,bi,bj) |
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guNm1(i,j,k,bi,bj)= gU(i,j,k,bi,bj) |
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gvNm1(i,j,k,bi,bj)= gV(i,j,k,bi,bj) |
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gU(i,j,k,bi,bj) = gUtmp(i,j) |
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gV(i,j,k,bi,bj) = gVtmp(i,j) |
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ENDDO |
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ENDDO |
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|
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C-- Forcing term outside the Adams-Bashforth: |
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C (not recommanded with CD-scheme ON) |
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IF (momForcing .AND. .NOT.momForcing_In_AB) THEN |
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CALL EXTERNAL_FORCING_U( |
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I iMin,iMax,jMin,jMax,bi,bj,k, |
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I myTime,myThid) |
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CALL EXTERNAL_FORCING_V( |
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I iMin,iMax,jMin,jMax,bi,bj,k, |
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I myTime,myThid) |
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IF (useCDscheme) THEN |
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C- for CD-scheme, compute gU,Vtmp = gU,V^n + forcing |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gUtmp(i,j) = gU(i,j,k,bi,bj)-gUtmp(i,j) |
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& + guNm1(i,j,k,bi,bj) |
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gVtmp(i,j) = gV(i,j,k,bi,bj)-gVtmp(i,j) |
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& + gvNm1(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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ELSE |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gUtmp(i,j) = gU(i,j,k,bi,bj) |
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gVtmp(i,j) = gV(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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ENDIF |
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ELSEIF ( useCDscheme) THEN |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gUtmp(i,j) = guNm1(i,j,k,bi,bj) |
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gVtmp(i,j) = gvNm1(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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ENDIF |
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|
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#ifdef INCLUDE_CD_CODE |
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#ifdef ALLOW_MOM_FLUXFORM |
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IF (useCDscheme) THEN |
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C- Step forward D-grid velocity using C-grid gU,Vtmp = gU,V^n + forcing |
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C and return coriolis terms on C-grid (guCor,gvCor) |
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CALL MOM_CDSCHEME( |
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I bi,bj,k, dPhiHydX,dPhiHydY, gUtmp,gVtmp, |
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O guCor,gvCor, |
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I myTime, myIter, myThid) |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gUtmp(i,j) = gU(i,j,k,bi,bj) |
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& + guCor(i,j) |
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gVtmp(i,j) = gV(i,j,k,bi,bj) |
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& + gvCor(i,j) |
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ENDDO |
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ENDDO |
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ENDIF |
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#endif /* ALLOW_MOM_FLUXFORM */ |
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#endif /* INCLUDE_CD_CODE */ |
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|
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#ifdef NONLIN_FRSURF |
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IF (.NOT. vectorInvariantMomentum |
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& .AND. nonlinFreeSurf.GT.1) THEN |
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IF (select_rStar.GT.0) THEN |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gUtmp(i,j) = gUtmp(i,j)/rStarExpW(i,j,bi,bj) |
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gVtmp(i,j) = gVtmp(i,j)/rStarExpS(i,j,bi,bj) |
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ENDDO |
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ENDDO |
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ELSE |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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IF ( k.EQ.ksurfW(i,j,bi,bj) ) THEN |
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gUtmp(i,j) = gUtmp(i,j) |
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& *hFacW(i,j,k,bi,bj)/hFac_surfW(i,j,bi,bj) |
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ENDIF |
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IF ( k.EQ.ksurfS(i,j,bi,bj) ) THEN |
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gVtmp(i,j) = gVtmp(i,j) |
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& *hFacS(i,j,k,bi,bj)/hFac_surfS(i,j,bi,bj) |
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ENDIF |
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ENDDO |
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ENDDO |
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ENDIF |
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ENDIF |
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#endif /* NONLIN_FRSURF */ |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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|
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C Step forward zonal velocity (store in Gu) |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gU(i,j,k,bi,bj) = uVel(i,j,k,bi,bj) |
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& +deltaTmom*( |
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& gUtmp(i,j) |
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& - psFac*phiSurfX(i,j) |
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& - phxFac*dPhiHydX(i,j) |
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& )*_maskW(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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|
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C Step forward meridional velocity (store in Gv) |
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DO j=jMin,jMax |
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DO i=iMin,iMax |
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gV(i,j,k,bi,bj) = vVel(i,j,k,bi,bj) |
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& +deltaTmom*( |
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& gVtmp(i,j) |
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& - psFac*phiSurfY(i,j) |
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& - phyFac*dPhiHydY(i,j) |
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& )*_maskS(i,j,k,bi,bj) |
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ENDDO |
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ENDDO |
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|
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RETURN |
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END |
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