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C Copyright 1981-2016 ECMWF.
C
C This software is licensed under the terms of the Apache Licence
C Version 2.0 which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
C
C In applying this licence, ECMWF does not waive the privileges and immunities
C granted to it by virtue of its status as an intergovernmental organisation
C nor does it submit to any jurisdiction.
C
INTEGER FUNCTION NEWISL(OLDGEO,NEWGEO,OLDLSM,OLDFLD,MASTER,NEWFLD)
C
C---->
C**** NEWISL
C
C Purpose
C -------
C
C Interpolate a field based on an old land-sea mask to a field
C based on a different land-sea mask.
C
C
C Interface
C ---------
C
C IRET = NEWISL(OLDGEO,NEWGEO,OLDLSM,OLDFLD,MASTER,NEWFLD)
C
C Input
C -----
C
C OLDGEO - GRIB section 2 describing grid of old field.
C NEWGEO - GRIB section 2 describing grid of new field.
C OLDLSM - Array of land-sea mask values for old field.
C OLDFLD - Array of values for old field.
C MASTER - Array of land-sea mask values for new field.
C
C
C Output
C ------
C
C NEWFLD - Array of values for new field.
C
C Function returns:
C - 0 if all is well
C - 1, otherwise.
C
C
C Method
C ------
C
C Build up field offsets from input geometries.
C For each point of the new field, find in the old field the four
C nearest neighbours' positions, values and types.
C Calculate new value from the neighbours.
C
C
C Externals
C ---------
C
C IGGLAT - Compute gaussian lines of latitude.
C JNORSGG - Find gaussian latitudes to north and south of latitude.
C ISLPROC - Calculate value of new field point.
C INTLOG - Log messages
C
C
C Author
C ------
C
C J.D.Chambers ECMWF August 2000
C
C----<
C
IMPLICIT NONE
C
C Function arguments
C
INTEGER OLDGEO(*),NEWGEO(*)
REAL OLDLSM(*),OLDFLD(*),MASTER(*),NEWFLD(*)
C
#include "intisl.h"
#include "parim.h"
C
C Parameters
C
INTEGER JPMAXLT, JPGAUSS, JP1000
PARAMETER (JPMAXLT=721)
PARAMETER (JPGAUSS=4)
PARAMETER (JP1000=1000)
C
C Local variables
C
INTEGER TOTAL, NEXT, LOOP, NEWOFF(JPMAXLT), OLDOFF(JPMAXLT)
INTEGER LATIT, LONG, NEWTYPE, IRET, NPTS
INTEGER LAT(2), LON(4)
INTEGER PT(4), TYPE(4)
REAL OLAT(2), OLON(4)
REAL RLATOLD(JPMAXLT), RLATNEW(JPMAXLT), RLAT, RLON
C
C Externals
C
INTEGER IGGLAT, JNORSGG
REAL ISLPROC
EXTERNAL IGGLAT, JNORSGG, ISLPROC
C
C -----------------------------------------------------------------|
C* Section 1. Build working values using input geometries.
C -----------------------------------------------------------------|
C
100 CONTINUE
C
NEWISL = 0
C
C -----------------------------------------------------------------|
C* Section 2. Calculate number of points in new field and offset
C to start of each latitude in the new grid
C -----------------------------------------------------------------|
C
200 CONTINUE
C
IF( NEWGEO(1).EQ.JPGAUSS ) THEN
C
C New field is gaussian
C
CALL INTLOG(JP_DEBUG,'NEWISL: New field is gaussian',JPQUIET)
C
IF( NEWGEO(17).EQ.0 ) THEN
CALL INTLOG(JP_DEBUG,'NEWISL: New field is regular',JPQUIET)
TOTAL = NEWGEO(2)*NEWGEO(3)
NEWOFF(1) = 0
DO LOOP = 2, NEWGEO(NJ)
NEWOFF(LOOP) = NEWOFF(LOOP-1) + NEWGEO(2)
ENDDO
ELSE
CALL INTLOG(JP_DEBUG,'NEWISL: New field is reduced',JPQUIET)
NEWOFF(1) = 0
TOTAL = NEWGEO(NPOINTS)
DO LOOP = 2, NEWGEO(NJ)
NEWOFF(LOOP) = NEWOFF(LOOP-1) + NEWGEO(NPOINTS-2+LOOP)
TOTAL = TOTAL + NEWGEO(NPOINTS-1+LOOP)
ENDDO
ENDIF
C
C Get the gaussian latitudes for the new field
C
IRET = IGGLAT(NEWGEO(NGAUSS)*2,RLATNEW,0,-1)
IF( IRET.NE.0 ) THEN
WRITE(*,*) 'NEWISL: Problem call igglat for new grid'
NEWISL = 1
RETURN
ENDIF
C
ELSE
C
C New field is lat/long
C
CALL INTLOG(JP_DEBUG,'NEWISL: New field is lat/long',JPQUIET)
TOTAL = NEWGEO(2)*NEWGEO(3)
DO LOOP = 1, NEWGEO(3)
NEWOFF(LOOP) = NEWGEO(2)*(LOOP-1)
RLATNEW(LOOP) = 90.0 - (REAL((LOOP-1)*NEWGEO(10))/JP1000)
ENDDO
C
ENDIF
C
CALL INTLOG(JP_DEBUG,'NEWISL: No. of pts in new field = ',TOTAL)
C
C -----------------------------------------------------------------|
C* Section 3. Get the gaussian latitudes for the old field and
C setup the offsets to the start of each latitude.
C -----------------------------------------------------------------|
C
300 CONTINUE
C
OLDOFF(1) = 0
DO LOOP = 2, OLDGEO(NJ)
OLDOFF(LOOP) = OLDOFF(LOOP-1) + OLDGEO(NPOINTS-2+LOOP)
ENDDO
C
IRET = IGGLAT(OLDGEO(NGAUSS)*2,RLATOLD,0,-1)
IF( IRET.NE.0 ) THEN
WRITE(*,*) 'NEWISL: Problem call igglat for old grid'
NEWISL = 1
RETURN
ENDIF
C
C -----------------------------------------------------------------|
C* Section 4. Work through the points in the new field.
C -----------------------------------------------------------------|
C
400 CONTINUE
C
DO NEXT = 1, TOTAL
C
C Calculate lat/long
C
DO LOOP = 1, NEWGEO(NJ)
IF( NEWOFF(LOOP).GE.NEXT ) THEN
LATIT = LOOP - 1
GOTO 410
ENDIF
ENDDO
LATIT = NEWGEO(NJ)
C
410 CONTINUE
C
LONG = NEXT - NEWOFF(LATIT)
C
RLAT = RLATNEW(LATIT)
IF( NEWGEO(1).EQ.JPGAUSS ) THEN
IF( NEWGEO(17).EQ.0 ) THEN
RLON = REAL((LONG-1)*NEWGEO(9))/JP1000
ELSE
RLON = (REAL(LONG-1)*360.0)/REAL(NEWGEO(NPOINTS+LATIT-1))
ENDIF
ELSE
RLON = REAL((LONG-1)*NEWGEO(9))/JP1000
ENDIF
C
C Find type of point (land or sea)
C
IF( MASTER(NEXT).GT.MASTERTHRESHOLD ) THEN
NEWTYPE = LAND
ELSE
NEWTYPE = SEA
ENDIF
C
C Find four neighbours in the old field with their types
C (Find NW neighbour and deduce the others).
C
LAT(NORTH) = JNORSGG(RLAT,RLATOLD,OLDGEO(NGAUSS),1)
LAT(SOUTH) = JNORSGG(RLAT,RLATOLD,OLDGEO(NGAUSS),0)
C
OLAT(NORTH) = RLATOLD(LAT(NORTH))
OLAT(SOUTH) = RLATOLD(LAT(SOUTH))
C
NPTS = OLDGEO(NPOINTS-1+LAT(NORTH))
LON(NWEST) = 1 + INT(RLON/(360.0/REAL(NPTS)))
LON(NEAST) = LON(NWEST) + 1
IF( LON(NEAST).GT.NPTS ) LON(NEAST) = 1
C
OLON(NWEST) = (REAL(LON(NWEST)-1)*360.0)/REAL(NPTS)
IF( LON(NEAST).EQ.1 ) THEN
OLON(NEAST) = 360.0
ELSE
OLON(NEAST) = (REAL(LON(NEAST)-1)*360.0)/REAL(NPTS)
ENDIF
C
NPTS = OLDGEO(NPOINTS-1+LAT(SOUTH))
LON(SWEST) = 1 + INT(RLON/(360.0/REAL(NPTS)))
LON(SEAST) = LON(SWEST) + 1
IF( LON(SEAST).GT.NPTS ) LON(SEAST) = 1
C
OLON(SWEST) = (REAL(LON(SWEST)-1)*360.0)/REAL(NPTS)
IF( LON(SEAST).EQ.1 ) THEN
OLON(SEAST) = 360.0
ELSE
OLON(SEAST) = (REAL(LON(SEAST)-1)*360.0)/REAL(NPTS)
ENDIF
C
PT(NWEST) = OLDOFF(LAT(NORTH)) + LON(NWEST)
IF( OLDLSM(PT(NWEST)).GT.OLDLSMTHRESHOLD ) THEN
TYPE(NWEST) = LAND
ELSE
TYPE(NWEST) = SEA
ENDIF
C
PT(NEAST) = OLDOFF(LAT(NORTH)) + LON(NEAST)
IF( OLDLSM(PT(NEAST)).GT.OLDLSMTHRESHOLD ) THEN
TYPE(NEAST) = LAND
ELSE
TYPE(NEAST) = SEA
ENDIF
C
PT(SWEST) = OLDOFF(LAT(SOUTH)) + LON(SWEST)
IF( OLDLSM(PT(SWEST)).GT.OLDLSMTHRESHOLD ) THEN
TYPE(SWEST) = LAND
ELSE
TYPE(SWEST) = SEA
ENDIF
C
PT(SEAST) = OLDOFF(LAT(SOUTH)) + LON(SEAST)
IF( OLDLSM(PT(SEAST)).GT.OLDLSMTHRESHOLD ) THEN
TYPE(SEAST) = LAND
ELSE
TYPE(SEAST) = SEA
ENDIF
C
C Interpolate the new value
C
NEWFLD(NEXT) =
X ISLPROC(RLAT,RLON,NEWTYPE,OLAT,OLON,TYPE,PT,OLDFLD)
C
ENDDO
C
C -----------------------------------------------------------------|
C* Section 9. Return
C -----------------------------------------------------------------|
C
900 CONTINUE
C
C
RETURN
END
|
