| 1 |
|
C $Header$ |
| 2 |
|
|
| 3 |
|
#include "ZONAL_FILT_OPTIONS.h" |
| 4 |
|
|
| 5 |
|
SUBROUTINE ZONAL_FILT_INIT(myThid) |
| 6 |
|
|
| 7 |
|
C /==========================================================\ |
| 8 |
|
C | S/R ZONAL_FILT_INIT | |
| 9 |
|
C | o Initialise FFT filter for latitude circle. | |
| 10 |
|
C |==========================================================| |
| 11 |
|
C | The details of particular FFT libraries may differ. | |
| 12 |
|
C | Changing to a different library may entail modifying the | |
| 13 |
|
C | code here. However, the broad process is usually the | |
| 14 |
|
C | same. | |
| 15 |
|
C | Note - Fourier modes for sNx and sNx+1 are damped in the | |
| 16 |
|
C | same way. This is because we have not implemented | |
| 17 |
|
C | a scheme that sets the damping factor for the | |
| 18 |
|
C | highest wave number for odd sNx. Instead the | |
| 19 |
|
C | highest wave number for odd sNx. Instead only | |
| 20 |
|
C | wave numbers 1:INT(sNx/2) are partially damped. | |
| 21 |
|
C | Wave number sNx/2 (if it exists) is removed | |
| 22 |
|
C | altogether. | |
| 23 |
|
C \==========================================================/ |
| 24 |
|
IMPLICIT NONE |
| 25 |
|
|
| 26 |
|
C == Global data == |
| 27 |
|
#include "SIZE.h" |
| 28 |
|
#include "EEPARAMS.h" |
| 29 |
|
#include "PARAMS.h" |
| 30 |
|
#include "GRID.h" |
| 31 |
|
#include "ZONAL_FILT.h" |
| 32 |
|
#include "FFTPACK.h" |
| 33 |
|
|
| 34 |
|
C == Routine arguments == |
| 35 |
|
C myThid - Thread number of this instance of FILTER_LATCIRC_FFT_INIT |
| 36 |
|
INTEGER myThid |
| 37 |
|
|
| 38 |
|
#ifdef ALLOW_ZONAL_FILT |
| 39 |
|
|
| 40 |
|
C == Local variables == |
| 41 |
|
C alpha - Used to evaluate frequency and latitude dependent |
| 42 |
|
C amplitude damping factor. |
| 43 |
|
C wvNum - Wave number |
| 44 |
|
C lat - Temporary holding latitude |
| 45 |
|
C nWv - No. of waves that fit on grid. |
| 46 |
|
_RL alpha, wvNum, lat |
| 47 |
|
INTEGER I, J, bi, bj, nPoints, nWv |
| 48 |
|
_RL one |
| 49 |
|
PARAMETER( one = 1.0 ) |
| 50 |
|
_RS ampfact,Y |
| 51 |
|
_RL yGCur |
| 52 |
|
ampfact(Y,I) = min( one, |
| 53 |
|
& ( cos( abs(Y)*deg2rad ) |
| 54 |
|
& /cos( zonal_filt_lat*deg2rad ) )**zonal_filt_cospow |
| 55 |
|
& /(sin( PI*float(I)/float(Nx) ) )**zonal_filt_sinpow |
| 56 |
|
& ) |
| 57 |
|
|
| 58 |
|
C o Initialise specific library FFT package |
| 59 |
|
DO bj=1,nSy |
| 60 |
|
C CALL R8FFTI( Nx, FFTPACKWS(1,bj) ) |
| 61 |
|
CALL R8FFTI1( Nx, FFTPACKWS2(1,bj), FFTPACKWS3(1,bj) ) |
| 62 |
|
ENDDO |
| 63 |
|
|
| 64 |
|
C o Set amplitude scale factor as function of latitude and mode number |
| 65 |
|
DO bj=1,nSy |
| 66 |
|
DO bi=1,nSx |
| 67 |
|
DO j=1-oLy,sNy+Oly |
| 68 |
|
ampFactor(1,J,bi,bj) = one |
| 69 |
|
ampFactorV(1,J,bi,bj) = one |
| 70 |
|
yGCur=yG(1,J,bi,bj) |
| 71 |
|
DO i=1,Nx/2-1 |
| 72 |
|
ampFactor(2*I,J,bi,bj) = ampfact( yC(1,J,bi,bj) , I ) |
| 73 |
|
C IF (ampFactor(2*I,J,bi,bj).LE..9) ampFactor(2*I,J,bi,bj)=0. |
| 74 |
|
ampFactor(2*I+1,J,bi,bj) = ampFactor(2*I,J,bi,bj) |
| 75 |
|
ampFactorV(2*I,J,bi,bj) = ampfact( yGCur , I ) |
| 76 |
|
C IF (ampFactorV(2*I,J,bi,bj).LE..9) ampFactorV(2*I,J,bi,bj)=0. |
| 77 |
|
ampFactorV(2*I+1,J,bi,bj) = ampFactorV(2*I,J,bi,bj) |
| 78 |
|
ENDDO |
| 79 |
|
I=Nx/2 |
| 80 |
|
Cajatest |
| 81 |
|
ampFactor(Nx,J,bi,bj) = 0. |
| 82 |
|
ampFactorV(Nx,J,bi,bj) = 0. |
| 83 |
|
C ampFactor(Nx,J,bi,bj) = ampfact( yC(1,J,bi,bj) , I ) |
| 84 |
|
C ampFactorV(Nx,J,bi,bj) = ampfact( yG , I ) |
| 85 |
|
Cajatest |
| 86 |
|
ENDDO |
| 87 |
|
ENDDO |
| 88 |
|
ENDDO |
| 89 |
|
|
| 90 |
|
CALL WRITE_REC_XY_RL( 'ampFactor', ampFactor, 1, 0, myThid ) |
| 91 |
|
|
| 92 |
|
#endif /* ALLOW_ZONAL_FILT */ |
| 93 |
|
|
| 94 |
|
RETURN |
| 95 |
|
END |
Parent Directory
| 
Revision Log
| 
Revision Graph
| 
Patch