SUBROUTINE WNDCOR(KFILDO,P,IX,JY,NX,NY,MESH,IWINDX,IWINDY,F)
C
C APRIL 2001 GLAHN TDL LAMP-2000
C MAY 2001 GLAHN TESTED FOR 1013 UP FRONT; COMMENTS
C APRIL 2002 GLAHN CHANGED A FORMAT REFERENCE FROM
C 110 TO 120
C DECEMBER 2002 RUDACK MODIFIED FORMAT STATEMENTS TO ADHERE
C TO THE F90 COMPILER STANDARDS FOUND
C ON THE IBM SYSTEM
C MARCH 2010 GLAHN INITIALAIZED F = 0.
C OCTOBER 2012 ENGLE MODIFIED FORMAT STATEMENT
C 100 FOR INTEL COMPILER
C JUNE 2014 GLAHN INSERTED CALL TO W3TAGE BEFORE STOPS
C NOVEMBER 2014 GLAHN REVISED W3TAG PER JUDY
C
C PURPOSE
C TO DETERMINE WHICH POINTS IN THE GRID P( , ) SHOULD
C HAVE A WIND CORRECTION. THIS IS DEFINED TO BE
C A GRID POINT LE 1013 MB, IS LOWER THAN ALL POINTS
C WITHIN 240 KM ON EITHER SIDE, AND THE MINIMUM OF THE TWO
C END POINTS MINUS THE GRIDPOINT IN QUESTION IS TGRAD MB/KM
C (CURRENTLY SET AT .012 MB/KM). IF A POINT IS A MINIMUM
C IN EITHER THE IX OR JY DIRECTION, IT WILL HAVE A WIND
C CORRECTION. ALSO, THE ADJACENT TWO POINTS IN EITHER/AND
C THE IX OR JY DIRECTIONS WILL HAVE A FRACTIONAL
C CORRECTION (SEE F BELOW).
C
C DATA SET USE
C KFILDO - UNIT NUMBER FOR OUTPUT (PRINT) FILE. (OUTPUT)
C
C VARIABLES
C KFILDO = UNIT NUMBER FOR OUTPUT (PRINT) FILE. (INPUT)
C P(IX,JY) = FIELD TO SMOOTH (IX=1,NX) (JY=1,NY).
C (INPUT-OUTPUT)
C IX, JY = THE POINT IN P( , ) BEING DEALT WITH. (INPUT)
C NX, NY = DIMENSIONS OF P( , ). (INPUT)
C MESH = MESH LENGTH OF GRID IN P( , ). (INPUT)
C IWINDX = 1 WHEN WIND CORRECTION IS TO BE MADE AND
C POSSIBLY TO ADJACENT POINTS IN X DIRECTION.
C 0 OTHERWISE. (OUTPUT)
C IWINDY = 1 WHEN WIND CORRECTION IS TO BE MADE AND
C POSSIBLY TO ADJACENT POINTS IN Y DIRECTION.
C 0 OTHERWISE. (OUTPUT)
C F = FACTOR BY WHICH CORRECTION IS APPLIED TO POINTS
C ADJACENT TO MINIMUM. (OUTPUT)
C TGRAD = THE GRADIENT IN MB THAT MUST BE MET FOR THE
C WIND CORRECTION TO BE MADE. (INTERNAL)
C IFIRST = CONTROLS PRINTING OF F AND TGRAD. (INTERNAL)
C 1 2 3 4 5 6 7 X
C
C NONSYSTEM SUBROUTINES CALLED
C NONE.
C
DIMENSION P(NX,NY)
C
DATA IFIRST/0/
SAVE IFIRST
C
F=0
C THIS IS FOR SAFETY. IT IS NOT INITIALIZED IN CALLING PROGRAM.
C I DOUBT THIS ROUTINE AND USE OF WINDS IN SEA LEVEL PRESSURE
C ANALYSIS HAS EVER BEEN USED IN THIS VERSION. IT CAME FROM LAMP.
C
IF(P(IX,JY).GT.1013.)GO TO 140
C WIND CORRECTIONS ONLY APPLY WHEN PRESSURE GT 1013 MB.
C TEST IS HERE FOR SAFETY; TEST IS ALSO MADE IN CALLING ROUTINE.
F=.75
C F = 0 MEANS THE ADJACENT POINTS WILL NOT BE CORRECTED.
C F = 1 MEANS THE ADJACENT POINTS WILL BE CORRECTED.
C INTERMEDIATE VALUES ARE POSSIBLE FOR A LIGHT CORRECTION.
TGRAD=.012
C TGRAD IS IN MB PER KM.
IF(IFIRST.EQ.0)THEN
WRITE(KFILDO,100)F,TGRAD
100 FORMAT(/' FOR WIND CORRECTION, ADJACENT GRIDPOINTS ARE',
1 ' CORRECTED',F5.2,' OF A FULL CORRECTON.'/
2 ' THE THRESHOLD GRADIENT FOR CORRECTION IS',F6.3,
3 ' MB PER KM.')
IFIRST=1
ENDIF
C
IF(MESH.GT.160)THEN
WRITE(KFILDO,101)MESH
101 FORMAT(/'****MESH =',I8,' IN WNDCOR TOO LARGE.',
1 ' STOP IN WNDCOR AT 101.')
CALL W3TAGE('WNDCOR')
STOP 101
ENDIF
C
C OBTAIN MAX OF THE ENDPOINTS ALONG JY'TH ROW.
C THIS LOOKS MESH*3 GRIDLENGTHS OUT FOR AN 80 KM GRID AND
C LOOKS MESH*6 GRIDLENGTHS OUT FOR A 40 KM GRID. THIS
C WILL ALWAYS GET A MIN UNLESS THE GRID IS UNREALISTICALLY
C SMALL. IF THE GRIDPOINT IS LT 240 KM FROM AN EDGE,
C THE OPPOSITE DIRECTION IS USED FOR THE MIN.
C
XMAX=99999999.
C
IF(IX-(240/MESH).GE.1)THEN
XMAX=P(IX-(240/MESH),JY)
ENDIF
C
IF(IX+(240/MESH).LE.NX)THEN
C
IF(XMAX.EQ.99999999.)THEN
XMAX=P(IX+(240/MESH),JY)
ELSE
XMAX=MIN(XMAX,P(IX+(240/MESH),JY))
ENDIF
C
ENDIF
C
IF(XMAX.EQ.99999999.)THEN
WRITE(KFILDO,110)NX,NY
110 FORMAT(/' ****GRID UNREALISTICALLY SMALL.',
1 ' NX =',I5,' NY =',I5/
2 ' STOP AT 110 IN WNDCOR')
CALL W3TAGE('WNDCOR')
STOP 110
ENDIF
C
C OBTAIN MAX OF THE ENDPOINTS ALONG IX'TH COLUMN.
C THIS LOOKS MESH*3 GRIDLENGTHS OUT FOR AN 80 KM GRID AND
C LOOKS MESH*6 GRIDLENGTHS OUT FOR A 40 KM GRID. THIS
C WILL ALWAYS GET A MIN UNLESS THE GRID IS UNREALISTICALLY
C SMALL. IF THE GRIDPOINT IS LT 240 KM FROM AN EDGE,
C THE OPPOSITE DIRECTION IS USED FOR THE MIN.
C
YMAX=99999999.
C
IF(JY-(240/MESH).GE.1)THEN
YMAX=P(IX,JY-(240/MESH))
ENDIF
C
IF(JY+(240/MESH).LE.NY)THEN
C
IF(YMAX.EQ.99999999.)THEN
YMAX=P(IX,JY+(240/MESH))
ELSE
YMAX=MIN(YMAX,P(IX,JY+(240/MESH)))
ENDIF
C
ENDIF
C
IF(YMAX.EQ.99999999.)THEN
WRITE(KFILDO,120)NX,NY
120 FORMAT(/' ****GRID UNREALISTICALLY SMALL.',
1 ' NX =',I5,' NY =',I5/
2 ' STOP AT 120 IN WNDCOR')
CALL W3TAGE('WNDCOR')
STOP 120
ENDIF
C
XRANGE=XMAX-P(IX,JY)
YRANGE=YMAX-P(IX,JY)
IWINDX=0
IWINDY=0
C
C CHECK THE GRADIENT AND MINIMUM IN X DIRECTION.
C
IF(XRANGE/240..GT.TGRAD)THEN
C THE RANGE IS ALWAYS OVER 240 KM.
GRAD=XRANGE/240.
C*** WRITE(KFILDO,125)IX,JY,GRAD,TGRAD
C*** 125 FORMAT(/' WIND CORRECTION IN X-DIRECTION--',
C*** 1 'IX,JY,GRAD,TGRAD',2I5,3F8.3)
C
C THIS LOOP USED WHEN THE ANALYSIS LINES ARE ORIENTED MORE
C VERTICALLY THAN HORIZONTALLY. THEREFORE, LOOK ACROSS
C THE X AXIS FOR MINIMA TO NOT SMOOTH.
C
DO 130 M=-240/MESH,+240/MESH
IF(IX+M.LT.1.OR.IX+M.GT.NX)GO TO 130
IF(P(IX+M,JY).LT.P(IX,JY))GO TO 132
C POINT NOT A MINIMUN IN X DIRECTION, CHECK Y DIRECTION.
130 CONTINUE
C
C DROP THROUGH HERE MEANS THE POINT WAS A MINIMUM IN THE
C X DIRECTION AND THE GRADIENT MET THE CRITERIA IN THAT
C DIRECTION.
C
IWINDX=1
C
ENDIF
C
C CHECK THE GRADIENT AND MINIMUM IN Y DIRECTION.
C
132 IF(YRANGE/240..GT.TGRAD)THEN
C THE RANGE IS ALWAYS OVER 240 KM.
GRAD=YRANGE/240.
C*** WRITE(KFILDO,134)IX,JY,GRAD,TGRAD
C*** 134 FORMAT(/' WIND CORRECTION IN Y-DIRECTION--',
C*** 1 'IX,JY,GRAD,TGRAD',2I5,3F8.3)
C
C THIS LOOP USED WHEN THE ANALYSIS LINES ARE ORIENTED MORE
C HORIZONTALLY THAN VERTICALLY. THEREFORE, LOOK ALONG
C THE Y AXIS FOR MINIMA TO NOT SMOOTH.
C
DO 135 M=-240/MESH,+240/MESH
IF(JY+M.LT.1.OR.JY+M.GT.NY)GO TO 135
IF(P(IX,JY+M).LT.P(IX,JY))GO TO 140
C POINT NOT A MINIMUM.
135 CONTINUE
C
C DROP THROUGH HERE MEANS THE POINT WAS A MINIMUM IN THE
C Y DIRECTION AND THE GRADIENT MET THE CRITERIA IN THAT
C DIRECTION.
C
IWINDY=1
C
ENDIF
C
140 RETURN
END