| 1 | C $Header: /u/gcmpack/MITgcm/pkg/seaice/seaice_calc_strainrates.F,v 1.1 2007/04/20 18:29:58 mlosch Exp $ | 
| 2 | C $Name:  $ | 
| 3 |  | 
| 4 | #include "SEAICE_OPTIONS.h" | 
| 5 |  | 
| 6 | CStartOfInterface | 
| 7 | SUBROUTINE SEAICE_CALC_STRAINRATES( | 
| 8 | I     uFld, vFld, | 
| 9 | O     e11, e22, e12, | 
| 10 | I     myThid ) | 
| 11 | C     /==========================================================\ | 
| 12 | C     | SUBROUTINE  SEAICE_CALC_STRAINRATES                      | | 
| 13 | C     | o compute strain rates from ice velocities               | | 
| 14 | C     |==========================================================| | 
| 15 | C     | written by Martin Losch, Apr 2007                        | | 
| 16 | C     \==========================================================/ | 
| 17 | IMPLICIT NONE | 
| 18 |  | 
| 19 | C     === Global variables === | 
| 20 | #include "SIZE.h" | 
| 21 | #include "EEPARAMS.h" | 
| 22 | #include "PARAMS.h" | 
| 23 | #include "GRID.h" | 
| 24 | #include "SEAICE_PARAMS.h" | 
| 25 |  | 
| 26 | #ifdef ALLOW_AUTODIFF_TAMC | 
| 27 | # include "tamc.h" | 
| 28 | #endif | 
| 29 |  | 
| 30 | C     === Routine arguments === | 
| 31 | C     myThid - Thread no. that called this routine. | 
| 32 | INTEGER myThid | 
| 33 | C     ice velocities | 
| 34 | _RL uFld(1-Olx:sNx+Olx,1-Oly:sNy+Oly,nSx,nSy) | 
| 35 | _RL vFld(1-Olx:sNx+Olx,1-Oly:sNy+Oly,nSx,nSy) | 
| 36 | C     strain rate tensor | 
| 37 | _RL e11 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 38 | _RL e22 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 39 | _RL e12 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 40 | CEndOfInterface | 
| 41 |  | 
| 42 | #ifdef SEAICE_CGRID | 
| 43 | #ifdef SEAICE_ALLOW_DYNAMICS | 
| 44 | C     === Local variables === | 
| 45 | C     i,j,bi,bj - Loop counters | 
| 46 | INTEGER i, j, bi, bj | 
| 47 | C  hFacU, hFacV - determine the no-slip boundary condition | 
| 48 | INTEGER k | 
| 49 | _RS hFacU, hFacV | 
| 50 |  | 
| 51 |  | 
| 52 | C | 
| 53 | DO bj=myByLo(myThid),myByHi(myThid) | 
| 54 | DO bi=myBxLo(myThid),myBxHi(myThid) | 
| 55 | DO j=1-Oly+1,sNy+Oly-1 | 
| 56 | DO i=1-Olx+1,sNx+Olx-1 | 
| 57 | C NOW EVALUATE STRAIN RATES | 
| 58 | e11(I,J,bi,bj)= _recip_dxF(I,J,bi,bj) * | 
| 59 | &         (uFld(I+1,J,bi,bj)-uFld(I,J,bi,bj)) | 
| 60 | &         -HALF* | 
| 61 | &         (vFld(I,J,bi,bj)+vFld(I,J+1,bi,bj)) | 
| 62 | &         * _tanPhiAtU(I,J,bi,bj)*recip_rSphere | 
| 63 | e22(I,J,bi,bj)= _recip_dyF(I,J,bi,bj) * | 
| 64 | &         (vFld(I,J+1,bi,bj)-vFld(I,J,bi,bj)) | 
| 65 | C     one metric term is missing | 
| 66 | e12(I,J,bi,bj)=HALF*( | 
| 67 | &         (uFld(I  ,J  ,bi,bj) * _dxC(I  ,J  ,bi,bj) | 
| 68 | &         -uFld(I  ,J-1,bi,bj) * _dxC(I  ,J-1,bi,bj) | 
| 69 | &         +vFld(I  ,J  ,bi,bj) * _dyC(I  ,J  ,bi,bj) | 
| 70 | &         -vFld(I-1,J  ,bi,bj) * _dyC(I-1,J  ,bi,bj)) | 
| 71 | &         * recip_rAz(I,J,bi,bj) | 
| 72 | &         + | 
| 73 | &         0.25 _d 0 * (uFld(I,J,bi,bj)+uFld(I  ,J-1,bi,bj)) | 
| 74 | &         * ( _tanPhiAtU(I,J,bi,bj) + _tanPhiAtU(I,J-1,bi,bj) ) | 
| 75 | &         *recip_rSphere | 
| 76 | &         ) | 
| 77 | C     one metric term is missing | 
| 78 | ENDDO | 
| 79 | ENDDO | 
| 80 | IF ( SEAICE_no_slip ) THEN | 
| 81 | C     no slip boundary conditions are applied as a body force | 
| 82 | C     following mom_u/v_sidedrag | 
| 83 | k = 1 | 
| 84 | DO j=1-Oly+1,sNy+Oly-1 | 
| 85 | DO i=1-Olx+1,sNx+Olx-1 | 
| 86 | hFacU = _maskW(i,j,k,bi,bj) - _maskW(i,j-1,k,bi,bj) | 
| 87 | hFacV = _maskS(i,j,k,bi,bj) - _maskS(i-1,j,k,bi,bj) | 
| 88 |  | 
| 89 | e12(I,J,bi,bj)= e12(I,J,bi,bj) | 
| 90 | &          + HALF*( recip_rAz(i,j,bi,bj) | 
| 91 | &          *( hFacU * ( _dxC(i,j  ,bi,bj)*uFld(i,j  ,bi,bj) | 
| 92 | &                     + _dxC(i,j-1,bi,bj)*uFld(i,j-1,bi,bj) ) | 
| 93 | &           + hFacV * ( _dyC(i  ,j,bi,bj)*vFld(i  ,j,bi,bj) | 
| 94 | &                     + _dyC(i-1,j,bi,bj)*vFld(i-1,j,bi,bj) ) ) | 
| 95 | &         - hFacU | 
| 96 | &         * 0.25 _d 0 * (uFld(I,J,bi,bj)+uFld(I  ,J-1,bi,bj)) | 
| 97 | &         * ( _tanPhiAtU(I,J,bi,bj) + _tanPhiAtU(I,J-1,bi,bj) ) | 
| 98 | &         *recip_rSphere | 
| 99 | &          ) | 
| 100 | C     one metric term is missing | 
| 101 | ENDDO | 
| 102 | ENDDO | 
| 103 |  | 
| 104 | ENDIF | 
| 105 | ENDDO | 
| 106 | ENDDO | 
| 107 | #endif /* SEAICE_ALLOW_DYNAMICS */ | 
| 108 | #endif /* SEAICE_CGRID */ | 
| 109 | RETURN | 
| 110 | END |