C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_fluxlimit_adv_x.F,v 1.12 2008/02/29 01:30:59 mlosch Exp $ C $Name: $ #include "GAD_OPTIONS.h" CBOP C !ROUTINE: GAD_FLUXLIMIT_ADV_X C !INTERFACE: ========================================================== SUBROUTINE GAD_FLUXLIMIT_ADV_X( I bi,bj,k, calcCFL, deltaTloc, I uTrans, uFld, I maskLocW, tracer, O uT, I myThid ) C !DESCRIPTION: C Calculates the area integrated zonal flux due to advection of a tracer C using second-order interpolation with a flux limiter: C \begin{equation*} C F^x_{adv} = U \overline{ \theta }^i C - \frac{1}{2} \left( C [ 1 - \psi(C_r) ] |U| C + U \frac{u \Delta t}{\Delta x_c} \psi(C_r) C \right) \delta_i \theta C \end{equation*} C where the $\psi(C_r)$ is the limiter function and $C_r$ is C the slope ratio. C !USES: =============================================================== IMPLICIT NONE #include "SIZE.h" #include "GRID.h" C !INPUT PARAMETERS: =================================================== C bi,bj :: tile indices C k :: vertical level C calcCFL :: =T: calculate CFL number ; =F: take uFld as CFL C deltaTloc :: local time-step (s) C uTrans :: zonal volume transport C uFld :: zonal flow / CFL number C tracer :: tracer field C myThid :: thread number INTEGER bi,bj,k LOGICAL calcCFL _RL deltaTloc _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL uFld (1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RS maskLocW(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy) INTEGER myThid C !OUTPUT PARAMETERS: ================================================== C uT :: zonal advective flux _RL uT (1-OLx:sNx+OLx,1-OLy:sNy+OLy) C !LOCAL VARIABLES: ==================================================== C i,j :: loop indices C Cr :: slope ratio C Rjm,Rj,Rjp :: differences at i-1,i,i+1 INTEGER i,j _RL Cr,Rjm,Rj,Rjp _RL uCFL C Statement function provides Limiter(Cr) #include "GAD_FLUX_LIMITER.h" CEOP DO j=1-Oly,sNy+Oly uT(1-Olx,j)=0. uT(2-Olx,j)=0. uT(sNx+Olx,j)=0. ENDDO DO j=1-Oly,sNy+Oly DO i=1-Olx+2,sNx+Olx-1 uCFL = uFld(i,j) IF ( calcCFL ) uCFL = ABS( uFld(i,j)*deltaTloc & *recip_dxC(i,j,bi,bj)*recip_deepFacC(k) ) Rjp=(tracer(i+1,j)-tracer( i ,j))*maskLocW(i+1,j) Rj =(tracer( i ,j)-tracer(i-1,j))*maskLocW( i ,j) Rjm=(tracer(i-1,j)-tracer(i-2,j))*maskLocW(i-1,j) IF (Rj.NE.0.) THEN IF (uTrans(i,j).GT.0) THEN Cr=Rjm/Rj ELSE Cr=Rjp/Rj ENDIF ELSE IF (uTrans(i,j).GT.0) THEN Cr=Rjm*1.E20 ELSE Cr=Rjp*1.E20 ENDIF ENDIF Cr=Limiter(Cr) uT(i,j) = & uTrans(i,j)*(Tracer(i,j)+Tracer(i-1,j))*0.5 _d 0 & -ABS(uTrans(i,j))*((1.-Cr)+uCFL*Cr) & *Rj*0.5 _d 0 ENDDO ENDDO RETURN END