1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
|
C Copyright 1981-2007 ECMWF
C
C Licensed under the GNU Lesser General Public License which
C incorporates the terms and conditions of version 3 of the GNU
C General Public License.
C See LICENSE and gpl-3.0.txt for details.
C
INTEGER FUNCTION WAVEXX2(NPARAM, NUMLATS, NPTS,
X NLATS, STEPNS, STEPWE,
X OLDWAVE,
X NEWWAVE, NORTH, WEST, PMISS)
C
C---->
C*****WAVEXX2*
C
C PURPOSE
C -------
C
C Interpolates wave fields (except 2D spectra).
C
C
C INTERFACE
C ---------
C
C IRET = WAVEXX2(NPARAM, NUMLATS, NLATS, STEPNS, STEPWE,
C X OLDWAVE, NEWIDX, DISTNEW,
C X NEWWAVE, NORTH, WEST, PMISS)
C
C Input arguments
C ---------------
C
C NUMLATS - Input lat number north-south
C NPTS - Array giving number of points along each latitude
C (empty latitudes have entry 0)
C NLATS - Number of points N-S in new grid
C STEPNS - Output grid north-south resolution (degrees)
C STEPWE - Output grid west-east resolution (degrees)
C OLDWAVE - Original wave field
C NORTH - Output grid northernmost latitude (degrees)
C WEST - Output grid westernmost longitude (degrees)
C PMISS - Missing data value
C
C Output arguments
C ----------------
C
C NEWWAVE - New wave field
C
C Function returns 0 if the interpolation was OK.
C
C
C METHOD
C ------
C
C Builds the index of neighbouring points for the output grid.
C Then works through the output grid points, checking for subarea
C boundaries and looking up neighbouring point values and weights.
C (Neighbours may have missing data).
C
C
C EXTERNALS
C ---------
C
C WAVEIDX - determines which nearest-neighbour values to use for
C interpolating to new output grid point
C NUMPTWE - Calculates number of grid points between west/east
C area boundaries
C INTLOG - Log error message
C
C
C REFERENCE
C ---------
C
C None.
C
C
C Author.
C -------
C
C S. Curic ECMWF Jun 2009
C
C
C
C----<
C
IMPLICIT NONE
C
C Parameters
C
#include "parim.h"
#include "nifld.common"
#include "nofld.common"
#include "grspace.h"
INTEGER JPROUTINE, JPMXLAT
PARAMETER (JPROUTINE = 40100)
PARAMETER (JPMXLAT = 1801)
INTEGER JPNW, JPNE, JPSW, JPSE, JPN, JPS
INTEGER JPDISNW, JPDISNE, JPDISSW, JPDISSE
PARAMETER (JPNW = 1)
PARAMETER (JPNE = 2)
PARAMETER (JPSW = 3)
PARAMETER (JPSE = 4)
PARAMETER (JPN = 5)
PARAMETER (JPS = 6)
PARAMETER (JPDISNW = 7)
PARAMETER (JPDISNE = 8)
PARAMETER (JPDISSW = 9)
PARAMETER (JPDISSE = 10)
C
C Subroutine arguments
C
INTEGER NPTS,NLATS
DIMENSION NPTS(*)
REAL STEPNS, STEPWE, OLDWAVE, NEWWAVE, NORTH, WEST, PMISS
DIMENSION OLDWAVE(*), NEWWAVE(*)
INTEGER NEWIDX
DIMENSION NEWIDX(4,1440*721)
REAL*4 DISTNEW
DIMENSION DISTNEW(10,1440*721)
INTEGER NUMLATS
C
C Local arguments
C
REAL RLATINC
REAL ONORTH,OSOUTH,OWEST, OEAST
INTEGER IEOFSET, IWOFSET, ISTART, IWEST
REAL SOUTH, PTLAT, AWEST, EAST, PTLONG
REAL REFVAL, SCALE
INTEGER NSPT1, INSPT, NEXP, NMANT, NRETA, NRETB, NLENG, NBIT
INTEGER NPARAM, ISCALE, NSCALE, IBITS, ITEMP
INTEGER IRET, IEDITN
INTEGER NEXT, NEXTWV, NROW, NCOL, INDEX
INTEGER MISSLAT, LOOP, NUMNEW, KOLDNUM, KNEWNUM
DIMENSION NUMNEW(JPMXLAT)
REAL OLDLATS, NEWLATS, ROWINC
DIMENSION OLDLATS(JPMXLAT), NEWLATS(JPMXLAT)
LOGICAL LDIREC
REAL*4 DISNW, DISNE, DISSW, DISSE
REAL*4 NW_PT, NE_PT, SW_PT, SE_PT
REAL*4 RAD
DATA RAD/0.017453293/
REAL*4 DI1N, DI1S, DI2N, DI2S, DK1, DK2
REAL*4 CNW_PT, CNE_PT, CSW_PT, CSE_PT
REAL*4 SNW_PT, SNE_PT, SSW_PT, SSE_PT
REAL*4 U1, U2, C1, C2, S1, S2, CC, SS
INTEGER INW, INE, ISW, ISE, JNW, JNE, JSW, JSE
C
C Externals
C
INTEGER WAVEIDX, NUMPTWE
EXTERNAL WAVEIDX, NUMPTWE
C
C ---------------------------------------------------------------------
C* Section 1. Initalisation.
C ---------------------------------------------------------------------
C
100 CONTINUE
C
WAVEXX2 = 0
C Initialise the bitmap value lookup function
C
MISSLAT = 0
ONORTH = FLOAT(NIAREA(1))/PPMULT
OSOUTH = FLOAT(NIAREA(3))/PPMULT
RLATINC = FLOAT(NIGRID(2))/PPMULT
C
C Calculate number of latitudes if grid had been full from
C North pole to South pole
C
IF( NUMLATS.GT.JPMXLAT ) THEN
CALL INTLOG(JP_ERROR,
X 'WAVEXX2: Number of latitudes in input grid = ',NUMLATS)
CALL INTLOG(JP_ERROR,
X 'WAVEXX2: And is greater than allowed maximum = ',JPMXLAT)
WAVEXX2 = JPROUTINE + 1
GOTO 900
ENDIF
C
C
C Fill an array with the number of points at each latitude for the
C input field.
C
IF(NIREPR.EQ.JPREDLL) THEN
CALL INTLOG(JP_ERROR,
X 'WAVEXX2: Input field is reduced latitude/longitude',NUMLATS)
C
C Input field is a reduced latitude/longitude grid
C
C .. but it may be 'pseudo-gaussian' in layout
C (ie global, symmetric about the equator but no latitude
C at the equator)
C
IF( (ONORTH.NE.90000).AND.(MOD(NUMLATS,2).EQ.0) ) THEN
C
C
DO LOOP = 1, NUMLATS
OLDLATS(LOOP) = ONORTH - (LOOP-1)*RLATINC
ENDDO
C
C
ELSE
C
DO LOOP = 1, NUMLATS
OLDLATS(LOOP) = 90.0 - (LOOP-1)*RLATINC
ENDDO
C
ENDIF
C
ELSE
C
C Input field is a regular latitude/longitude grid
C
C
DO LOOP = 1, NUMLATS
OLDLATS(LOOP) = 90.0 - (LOOP-1)*RLATINC
ENDDO
C
MISSLAT = (90.0 - ONORTH)/RLATINC
DO LOOP = 1, MISSLAT
NPTS(LOOP) = 0
ENDDO
KOLDNUM = 1 + NINT((90.0 - OSOUTH)/RLATINC)
DO LOOP = 1, (KOLDNUM-MISSLAT)
NPTS(LOOP+MISSLAT) = NIWE
ENDDO
DO LOOP = (KOLDNUM+1), NUMLATS
NPTS(LOOP) = 0
ENDDO
ENDIF
C
C ---------------------------------------------------------------------
C* Section 2. Setup number of points at each latitude for the
C output latitude/longitude field.
C ---------------------------------------------------------------------
C
200 CONTINUE
C
IF( (NOREPR.EQ.JPQUASI) .OR. (NOREPR.EQ.JPGAUSSIAN) ) THEN
C
C Reduced (quasi-regular) gaussian output
C
KNEWNUM = NOGAUSS*2
DO LOOP = 1, KNEWNUM
NUMNEW(LOOP) = NOLPTS(LOOP)
NEWLATS(LOOP) = ROGAUSS(LOOP)
ENDDO
C
ELSE IF( NOREPR.EQ.JPREDLL ) THEN
C
C Reduced (quasi-regular) lat/long output
C
KNEWNUM = NOREDLL
DO LOOP = 1, KNEWNUM
NUMNEW(LOOP) = NOLPTS(LOOP)
NEWLATS(LOOP) = ROREDLL(LOOP)
ENDDO
C
ELSE
C
C Regular output
C
MISSLAT = NINT((90.0 - NORTH)/STEPNS)
DO LOOP = 1, MISSLAT
NUMNEW(LOOP) = 0
ENDDO
DO LOOP = 1, NLATS
NUMNEW(LOOP+MISSLAT) = NINT(360.0/STEPWE)
ENDDO
C
KNEWNUM = MISSLAT + NLATS
DO LOOP = 1, KNEWNUM
NEWLATS(LOOP) = 90.0 - (LOOP-1)*STEPNS
ENDDO
C
ENDIF
C
C ---------------------------------------------------------------------
C* Section 3. Get the input GRIB field characteristics.
C ---------------------------------------------------------------------
C
300 CONTINUE
C
C Calculate the indices of the input grid points to be used for
C the output points
C
OWEST = FLOAT(NIAREA(2))/PPMULT
OEAST = FLOAT(NIAREA(4))/PPMULT
WAVEXX2 = WAVEIDX(NUMLATS,NPTS,OLDLATS,OWEST,OEAST,
X KNEWNUM, NUMNEW, NEWLATS,
X NEWIDX, DISTNEW)
IF( WAVEXX2.NE.0 ) THEN
CALL INTLOG(JP_ERROR,
X 'WAVEXX2: Unable to calculate output grid indices',JPQUIET)
WAVEXX2 = JPROUTINE + 2
GOTO 900
ENDIF
C
C Wave direction parameters need special handling
C (MWD, MDWW, MDPS, MDWI)
C
LDIREC = ( (NPARAM.EQ.230) .OR.
X (NPARAM.EQ.235) .OR.
X (NPARAM.EQ.238) .OR.
X (NPARAM.EQ.242) )
C
C ---------------------------------------------------------------------
C* Section 4. Work through the output subarea.
C ---------------------------------------------------------------------
C
400 CONTINUE
C
C Fill in the wave spectra values
C
NEXT = 0
NEXTWV = 0
C
SOUTH = NOAREA(3)/PPMULT
EAST = NOAREA(4)/PPMULT
ISTART = 0
C
C Work down through latitudes from north to south.
C
DO NROW = 1, KNEWNUM
C
C If inside north-south (subarea) boundaries ..
C
IF( (NOREPR.EQ.JPGAUSSIAN).OR.(NOREPR.EQ.JPQUASI) ) THEN
PTLAT = ROGAUSS(NROW)
ELSE
PTLAT = 90.0 - (NROW-1)*STEPNS
ENDIF
IF( (PTLAT.LE.NORTH).AND.(ABS(PTLAT-SOUTH).GT.-0.0005) ) THEN
C
C Calculate number of points between west boundary of area and
C Greenwich
C
ROWINC = 360.0/NUMNEW(NROW)
C
IWEST = INT(WEST/ROWINC)
IF( (WEST.GT.0.0).AND.(WEST.NE.(IWEST*ROWINC)) )
X IWEST = IWEST + 1
AWEST = IWEST * ROWINC
IWOFSET = NUMPTWE(AWEST,0.0,ROWINC)
IEOFSET = NUMPTWE(AWEST,EAST,ROWINC)
C
C Work through subarea longitudes from west to east.
C
DO NCOL = 1, NUMNEW(NROW)
PTLONG = AWEST + (NCOL-1)*ROWINC
NEXT = NUMPTWE(AWEST,PTLONG,ROWINC)
IF( (NEXT.LE.IEOFSET).AND.(NEXT.GE.0) ) THEN
C
C .. and inside west-east (subarea) boundaries
C
NEXT = 1 + NEXT - IWOFSET
IF( NEXT.LE.0) NEXT = NEXT + NUMNEW(NROW)
NEXT = NEXT + ISTART
NEXTWV = NEXTWV + 1
C
INW = NEWIDX(JPNW,NEXT)
INE = NEWIDX(JPNE,NEXT)
ISW = NEWIDX(JPSW,NEXT)
ISE = NEWIDX(JPSE,NEXT)
C
C Test if any of the four neighbouring points is missing.
C
IF( (INW.EQ.0) .OR. (OLDWAVE(INW).EQ.PMISS) .OR.
X (ISW.EQ.0) .OR. (OLDWAVE(ISW).EQ.PMISS) .OR.
X (INE.EQ.0) .OR. (OLDWAVE(INE).EQ.PMISS) .OR.
X (ISE.EQ.0) .OR. (OLDWAVE(ISE).EQ.PMISS) ) THEN
C
C If so, take nearest grid point value.
C
DISNW = DISTNEW(JPDISNW,NEXT)
DISNE = DISTNEW(JPDISNE,NEXT)
DISSW = DISTNEW(JPDISSW,NEXT)
DISSE = DISTNEW(JPDISSE,NEXT)
C
IF( (DISNW.LE.DISNE).AND.
X (DISNW.LE.DISSW).AND.
X (DISNW.LE.DISSE)) THEN
INDEX = INW
C
ELSE IF( (DISNE.LE.DISSW).AND.
X (DISNE.LE.DISSE) ) THEN
INDEX = INE
C
ELSE IF( (DISSW.LE.DISSE) ) THEN
INDEX = ISW
C
ELSE
INDEX = ISE
ENDIF
C
IF(INDEX.EQ.0.OR.(OLDWAVE(INDEX).EQ.PMISS)) THEN
C
C Nearest point is missing
C
NEWWAVE(NEXTWV) = PMISS
C
ELSE
NEWWAVE(NEXTWV) = OLDWAVE(INDEX)
ENDIF
C
ELSE
C
C Use bi-linear interpolation from four
C neighbouring sea points.
C
C
DI1N = DISTNEW(JPNW,NEXT)
DI2N = DISTNEW(JPNE,NEXT)
DI1S = DISTNEW(JPSW,NEXT)
DI2S = DISTNEW(JPSE,NEXT)
DK1 = DISTNEW(JPN,NEXT)
DK2 = DISTNEW(JPS,NEXT)
C
NW_PT = OLDWAVE(INW)
NE_PT = OLDWAVE(INE)
SW_PT = OLDWAVE(ISW)
SE_PT = OLDWAVE(ISE)
IF( .NOT. LDIREC ) THEN
U1 = NW_PT*DI2N + NE_PT*DI1N
U2 = SW_PT*DI2S + SE_PT*DI1S
NEWWAVE(NEXTWV) = U1*DK2 + U2*DK1
ELSE
C
C Fields representing a 'direction': resolve into
C components and interpolate each separately.
C
CNW_PT = COS(NW_PT*RAD)
CNE_PT = COS(NE_PT*RAD)
CSW_PT = COS(SW_PT*RAD)
CSE_PT = COS(SE_PT*RAD)
SNW_PT = SIN(NW_PT*RAD)
SNE_PT = SIN(NE_PT*RAD)
SSW_PT = SIN(SW_PT*RAD)
SSE_PT = SIN(SE_PT*RAD)
C1 = CNW_PT*DI2N + CNE_PT*DI1N
C2 = CSW_PT*DI2S + CSE_PT*DI1S
CC = C1*DK2 + C2*DK1
S1 = SNW_PT*DI2N + SNE_PT*DI1N
S2 = SSW_PT*DI2S + SSE_PT*DI1S
SS = S1*DK2 + S2*DK1
IF( SS.LT.0.0 ) THEN
NEWWAVE(NEXTWV) = ATAN2(SS,CC)/RAD + 360.0
ELSE
NEWWAVE(NEXTWV) = ATAN2(SS,CC)/RAD
ENDIF
ENDIF
ENDIF
ENDIF
ENDDO
C
ENDIF
ISTART = ISTART + NUMNEW(NROW)
ENDDO
C
C ---------------------------------------------------------------------
C* Section 9. Closedown.
C ---------------------------------------------------------------------
C
900 CONTINUE
RETURN
END
|
