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! $Header: /home/cvsroot/LMDZ4/libf/dyn3d/extrapol.F,v 1.1.1.1 2004/05/19 |
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! 12:53:07 lmdzadmin Exp $ |
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SUBROUTINE extrapol(pfild, kxlon, kylat, pmask, norsud, ldper, knbor, pwork) |
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IMPLICIT NONE |
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! OASIS routine (Adaptation: Laurent Li, le 14 mars 1997) |
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! Fill up missed values by using the neighbor points |
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INTEGER kxlon, kylat ! longitude and latitude dimensions (Input) |
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INTEGER knbor ! minimum neighbor number (Input) |
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LOGICAL norsud ! True if field is from North to South (Input) |
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LOGICAL ldper ! True if take into account the periodicity (Input) |
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REAL pmask ! mask value (Input) |
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REAL pfild(kxlon, kylat) ! field to be extrapolated (Input/Output) |
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REAL pwork(kxlon, kylat) ! working space |
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|
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REAL zwmsk |
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INTEGER incre, idoit, i, j, k, inbor, ideb, ifin, ilon, jlat |
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INTEGER ix(9), jy(9) ! index arrays for the neighbors coordinates |
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REAL zmask(9) |
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! We search over the eight closest neighbors |
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! j+1 7 8 9 |
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! j 4 5 6 Current point 5 --> (i,j) |
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! j-1 1 2 3 |
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! i-1 i i+1 |
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IF (norsud) THEN |
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DO j = 1, kylat |
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DO i = 1, kxlon |
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pwork(i, j) = pfild(i, kylat-j+1) |
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END DO |
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END DO |
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DO j = 1, kylat |
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DO i = 1, kxlon |
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pfild(i, j) = pwork(i, j) |
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END DO |
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END DO |
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END IF |
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incre = 0 |
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DO j = 1, kylat |
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DO i = 1, kxlon |
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pwork(i, j) = pfild(i, j) |
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END DO |
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END DO |
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! * To avoid problems in floating point tests |
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zwmsk = pmask - 1.0 |
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200 CONTINUE |
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incre = incre + 1 |
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DO j = 1, kylat |
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DO i = 1, kxlon |
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IF (pfild(i,j)>zwmsk) THEN |
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pwork(i, j) = pfild(i, j) |
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inbor = 0 |
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ideb = 1 |
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ifin = 9 |
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! * Fill up ix array |
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ix(1) = max(1, i-1) |
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ix(2) = i |
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ix(3) = min(kxlon, i+1) |
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ix(4) = max(1, i-1) |
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ix(5) = i |
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ix(6) = min(kxlon, i+1) |
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ix(7) = max(1, i-1) |
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ix(8) = i |
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ix(9) = min(kxlon, i+1) |
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! * Fill up iy array |
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jy(1) = max(1, j-1) |
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jy(2) = max(1, j-1) |
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jy(3) = max(1, j-1) |
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jy(4) = j |
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jy(5) = j |
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jy(6) = j |
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jy(7) = min(kylat, j+1) |
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jy(8) = min(kylat, j+1) |
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jy(9) = min(kylat, j+1) |
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! * Correct latitude bounds if southernmost or northernmost points |
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IF (j==1) ideb = 4 |
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IF (j==kylat) ifin = 6 |
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! * Account for periodicity in longitude |
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IF (ldper) THEN |
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IF (i==kxlon) THEN |
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ix(3) = 1 |
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ix(6) = 1 |
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ix(9) = 1 |
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ELSE IF (i==1) THEN |
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ix(1) = kxlon |
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ix(4) = kxlon |
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ix(7) = kxlon |
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END IF |
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ELSE |
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IF (i==1) THEN |
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ix(1) = i |
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ix(2) = i + 1 |
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ix(3) = i |
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ix(4) = i + 1 |
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ix(5) = i |
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ix(6) = i + 1 |
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END IF |
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IF (i==kxlon) THEN |
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ix(1) = i - 1 |
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ix(2) = i |
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ix(3) = i - 1 |
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ix(4) = i |
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ix(5) = i - 1 |
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ix(6) = i |
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END IF |
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IF (i==1 .OR. i==kxlon) THEN |
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jy(1) = max(1, j-1) |
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jy(2) = max(1, j-1) |
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jy(3) = j |
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jy(4) = j |
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jy(5) = min(kylat, j+1) |
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jy(6) = min(kylat, j+1) |
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ideb = 1 |
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ifin = 6 |
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IF (j==1) ideb = 3 |
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IF (j==kylat) ifin = 4 |
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END IF |
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END IF ! end for ldper test |
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! * Find unmasked neighbors |
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DO k = ideb, ifin |
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zmask(k) = 0. |
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ilon = ix(k) |
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jlat = jy(k) |
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IF (pfild(ilon,jlat)<zwmsk) THEN |
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zmask(k) = 1. |
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inbor = inbor + 1 |
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END IF |
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END DO |
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! * Not enough points around point P are unmasked; interpolation on P |
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! will be done in a future call to extrap. |
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IF (inbor>=knbor) THEN |
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pwork(i, j) = 0. |
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DO k = ideb, ifin |
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ilon = ix(k) |
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jlat = jy(k) |
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pwork(i, j) = pwork(i, j) + pfild(ilon, jlat)*zmask(k)/float( & |
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inbor) |
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END DO |
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END IF |
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END IF |
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END DO |
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END DO |
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! * 3. Writing back unmasked field in pfild |
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! ------------------------------------ |
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! * pfild then contains: |
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! - Values which were not masked |
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! - Interpolated values from the inbor neighbors |
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! - Values which are not yet interpolated |
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idoit = 0 |
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DO j = 1, kylat |
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DO i = 1, kxlon |
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IF (pwork(i,j)>zwmsk) idoit = idoit + 1 |
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pfild(i, j) = pwork(i, j) |
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END DO |
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END DO |
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IF (idoit/=0) GO TO 200 |
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! cc PRINT*, "Number of extrapolation steps incre =", incre |
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IF (norsud) THEN |
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DO j = 1, kylat |
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DO i = 1, kxlon |
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pwork(i, j) = pfild(i, kylat-j+1) |
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END DO |
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END DO |
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DO j = 1, kylat |
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DO i = 1, kxlon |
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pfild(i, j) = pwork(i, j) |
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END DO |
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END DO |
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END IF |
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RETURN |
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END SUBROUTINE extrapol |