C $Header: /u/gcmpack/MITgcm/pkg/flt/flt_runga2.F,v 1.18 2011/12/22 19:04:45 jmc Exp $ C $Name: $ #include "FLT_OPTIONS.h" #undef _USE_INTEGERS SUBROUTINE FLT_RUNGA2 ( I myTime, myIter, myThid ) C ================================================================== C SUBROUTINE FLT_RUNGA2 C ================================================================== C o This routine steps floats forward with second order Runge-Kutta C C started: Arne Biastoch C C changed: 2004.06.10 Antti Westerlund (antti.westerlund@helsinki.fi) C and Sergio Jaramillo (sju@eos.ubc.ca) C ================================================================== C !USES: IMPLICIT NONE C == global variables == #include "SIZE.h" #include "EEPARAMS.h" #include "PARAMS.h" #include "GRID.h" #include "DYNVARS.h" #include "FLT_SIZE.h" #include "FLT.h" C == routine arguments == _RL myTime INTEGER myIter, myThid C == Functions == #ifdef USE_FLT_ALT_NOISE Real*8 PORT_RAND_NORM EXTERNAL PORT_RAND_NORM #else Real*8 PORT_RAND EXTERNAL PORT_RAND #ifdef _USE_INTEGERS INTEGER seed #else Real*8 seed #endif #endif /* USE_FLT_ALT_NOISE */ C == local variables == INTEGER bi, bj INTEGER ip INTEGER ic, jc, kc, iG, jG _RL uu, vv, u1, v1 #ifdef ALLOW_3D_FLT _RL ww, w1, ktz, kz, scalez _RL kzlo, kzhi #endif _RL ix, jy, itx, jty _RL scalex, scaley C == end of interface == #ifndef USE_FLT_ALT_NOISE #ifdef _USE_INTEGERS seed = -1 #else seed = -1.d0 #endif #endif /* ndef USE_FLT_ALT_NOISE */ #ifdef ALLOW_3D_FLT kzlo = 0.5 _d 0 kzhi = 0.5 _d 0 + DFLOAT(Nr) #endif DO bj=myByLo(myThid),myByHi(myThid) DO bi=myBxLo(myThid),myBxHi(myThid) DO ip=1,npart_tile(bi,bj) C If float has died move to level 0 IF ( tend(ip,bi,bj).NE.-1. .AND. myTime.GT.tend(ip,bi,bj) & ) THEN kpart(ip,bi,bj) = 0. ELSE C Start integration between tstart and tend (individual for each float) IF ( (tstart(ip,bi,bj).EQ.-1..OR.myTime.GE.tstart(ip,bi,bj)) & .AND.( tend(ip,bi,bj).EQ.-1..OR.myTime.LE. tend(ip,bi,bj)) & .AND.( iup(ip,bi,bj).NE.-3.) & ) THEN ix = ipart(ip,bi,bj) jy = jpart(ip,bi,bj) ic=NINT(ix) jc=NINT(jy) kc=NINT(kpart(ip,bi,bj)) scalex=recip_dxF(ic,jc,bi,bj) scaley=recip_dyF(ic,jc,bi,bj) iG = myXGlobalLo + (bi-1)*sNx + ic-1 jG = myYGlobalLo + (bj-1)*sNy + jc-1 #ifdef ALLOW_3D_FLT IF (iup(ip,bi,bj).EQ.-1.) THEN c kz=global2local_k(kpart(ip,bi,bj),bi,bj,mjtyhid) C recip_drF is in units 1/r (so IF r is in m this is in 1/m) scalez=rkSign*recip_drF(kc) C We should not do any special conversions for kz, since flt_trilinear C expects it to be just a normal kpart type variable. kz=kpart(ip,bi,bj) CALL FLT_TRILINEAR(ix,jy,kz,uu,uVel,1,bi,bj,myThid) CALL FLT_TRILINEAR(ix,jy,kz,vv,vVel,2,bi,bj,myThid) CALL FLT_TRILINEAR(ix,jy,kz,ww,wVel,4,bi,bj,myThid) ELSE #else /* ALLOW_3D_FLT */ IF ( .TRUE. ) THEN #endif /* ALLOW_3D_FLT */ CALL FLT_BILINEAR(ix,jy,uu,uVel,kc,1,bi,bj,myThid) CALL FLT_BILINEAR(ix,jy,vv,vVel,kc,2,bi,bj,myThid) ENDIF C When using this alternative scheme the noise probably should not be added twice. #ifndef USE_FLT_ALT_NOISE IF ( flt_noise.NE.0. .AND. iup(ip,bi,bj).NE.-2. ) THEN uu = uu + uu*(PORT_RAND(seed)-0.5)*flt_noise vv = vv + vv*(PORT_RAND(seed)-0.5)*flt_noise #ifdef ALLOW_3D_FLT #ifdef ALLOW_FLT_3D_NOISE IF (iup(ip,bi,bj).EQ.-1.) THEN ww = ww + ww*(PORT_RAND(seed)-0.5)*flt_noise ENDIF #endif #endif /* ALLOW_3D_FLT */ ENDIF #endif /* ndef USE_FLT_ALT_NOISE */ C ix and itx are in indices. Therefore it is necessary to multiply C with a grid scale factor. itx=ix+0.5*flt_deltaT*uu*scalex jty=jy+0.5*flt_deltaT*vv*scaley C Second step #ifdef ALLOW_3D_FLT IF (iup(ip,bi,bj).EQ.-1.) THEN ktz=kz+0.5*flt_deltaT*ww*scalez CALL FLT_TRILINEAR(itx,jty,ktz,u1,uVel,1,bi,bj,myThid) CALL FLT_TRILINEAR(itx,jty,ktz,v1,vVel,2,bi,bj,myThid) CALL FLT_TRILINEAR(itx,jty,ktz,w1,wVel,4,bi,bj,myThid) ELSE #else /* ALLOW_3D_FLT */ IF ( .TRUE. ) THEN #endif /* ALLOW_3D_FLT */ CALL FLT_BILINEAR(itx,jty,u1,uVel,kc,1,bi,bj,myThid) CALL FLT_BILINEAR(itx,jty,v1,vVel,kc,2,bi,bj,myThid) ENDIF IF ( flt_noise.NE.0. .AND. iup(ip,bi,bj).NE.-2. ) THEN #ifdef USE_FLT_ALT_NOISE u1 = u1 + PORT_RAND_NORM()*flt_noise v1 = v1 + PORT_RAND_NORM()*flt_noise #ifdef ALLOW_3D_FLT #ifdef ALLOW_FLT_3D_NOISE IF (iup(ip,bi,bj).EQ.-1.) THEN w1 = w1 + PORT_RAND_NORM()*flt_noise ENDIF #endif #endif /* ALLOW_3D_FLT */ #else /* USE_FLT_ALT_NOISE */ u1 = u1 + u1*(PORT_RAND(seed)-0.5)*flt_noise v1 = v1 + v1*(PORT_RAND(seed)-0.5)*flt_noise #ifdef ALLOW_3D_FLT #ifdef ALLOW_FLT_3D_NOISE IF (iup(ip,bi,bj).EQ.-1.) THEN w1 = w1 + w1*(PORT_RAND(seed)-0.5)*flt_noise ENDIF #endif #endif /* ALLOW_3D_FLT */ #endif /* USE_FLT_ALT_NOISE */ ENDIF C ipart is in coordinates. Therefore it is necessary to multiply C with a grid scale factor divided by the number grid points per C geographical coordinate. ipart(ip,bi,bj) = ipart(ip,bi,bj) & + flt_deltaT*u1*scalex jpart(ip,bi,bj) = jpart(ip,bi,bj) & + flt_deltaT*v1*scaley #ifdef ALLOW_3D_FLT IF (iup(ip,bi,bj).EQ.-1.) THEN kpart(ip,bi,bj) = kpart(ip,bi,bj) & + flt_deltaT*w1*scalez ENDIF #endif /* ALLOW_3D_FLT */ C-- new horizontal grid indices ic = MAX( 1-OLx, MIN( NINT(ipart(ip,bi,bj)), sNx+OLx ) ) jc = MAX( 1-OLy, MIN( NINT(jpart(ip,bi,bj)), sNy+OLy ) ) #ifdef ALLOW_3D_FLT C If float is 3D, make sure that it remains in water IF (iup(ip,bi,bj).EQ.-1.) THEN C reflect on surface IF (kpart(ip,bi,bj).LT.kzlo) kpart(ip,bi,bj)=kzlo & +kzlo-kpart(ip,bi,bj) C stop at bottom IF (kpart(ip,bi,bj).GT.kzhi) kpart(ip,bi,bj)=kzhi C-to work also with non flat-bottom set-up: c IF ( kpart(ip,bi,bj).GT.kLowC(ic,jc,bi,bj)+0.5 ) c & kpart(ip,bi,bj) = kLowC(ic,jc,bi,bj)+0.5 ENDIF #endif /* ALLOW_3D_FLT */ #ifdef ALLOW_OBCS IF ( useOBCS ) THEN C-- stop floats which enter the OB region: IF ( maskInC(ic,jc,bi,bj).EQ.0. .AND. & maskC(ic,jc,1,bi,bj).EQ.1. ) THEN C for now, just reset "tend" to myTime-deltaT C (a better way would be to remove this one & re-order the list of floats) tend(ip,bi,bj) = myTime - flt_deltaT ENDIF ENDIF #endif /* ALLOW_OBCS */ ENDIF ENDIF C- end ip loop ENDDO C- end bi,bj loops ENDDO ENDDO RETURN END