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21 michaesp 1
c     ************************************************************
2
c     * This package provides input routines to read the wind    *
3
c     * and other fields from IVE necdf files. The routines are  *
4
c     *                                                          *
5
c     * 1) input_open  : to open a data file                     *
6
c     * 2) input_grid  : to read the grid information, including *
7
c     *                  the vertical levels                     *
8
c     * 3) input_wind  : to read the wind components             *
9
c     * 4) input_close : to close an input file                  *
10
c     *                                                          *
11
c     * The file is characterised by an filename <filename> and  *
12
c     * a file identifier <fid>. The horizontal grid is given by *
13
c     * <xmin,xmax,ymin,ymax,dx,dy,nx,ny> where the pole of the  *
14
c     * rotated grid is given by <pollon,pollat>. The vertical   *
15
c     * grid is characterised by the surface pressure <ps> and   *
16
c     * the pressure at staggered <slev> and unstaggered <ulev>  *
17
c     * levels. The number of levels is given by <nz>. Finally,  *
18
c     * the retrieval of the wind <field> with name <fieldname>  *
19
c     * is characterised by a <time> and a missing data value    *
20
c     * <mdv>.                                                   *
21
c     *                                                          *
22
c     * Author: Michael Sprenger, Autumn 2008                    *
23
c     ************************************************************
24
 
25
c     ------------------------------------------------------------
26
c     Open input file
27
c     ------------------------------------------------------------
28
 
29
      subroutine input_open (fid,filename)
30
 
31
c     Open the input file with filename <filename> and return the
32
c     file identifier <fid> for further reference. 
33
 
34
      use netcdf
35
 
36
      implicit none
37
 
38
c     Declaration of subroutine parameters
39
      integer      fid              ! File identifier
40
      character*80 filename         ! Filename
41
 
42
c     Declaration of auxiliary variables
43
      integer      ierr
44
 
45
c     Open netcdf file
46
      ierr = NF90_OPEN(TRIM(filename),nf90_nowrite, fid)
47
      IF ( ierr /= nf90_NoErr ) PRINT *,NF90_STRERROR(ierr)
48
 
49
c     Exception handling
50
      return
51
 
52
      end
53
 
54
c     ------------------------------------------------------------
55
c     Read information about the grid
56
c     ------------------------------------------------------------
57
 
58
      subroutine input_grid 
59
     >                   (fid,fieldname,xmin,xmax,ymin,ymax,dx,dy,nx,ny,
60
     >                    time,pollon,pollat,p3,ps,nz,ak,bk,stagz,
61
     >                    timecheck)
62
 
63
c     Read grid information at <time> from file with identifier <fid>. 
64
c     The horizontal grid is characterized by <xmin,xmax,ymin,ymax,dx,dy>
65
c     with pole position at <pollon,pollat> and grid dimension <nx,ny>.
66
c     The 3d arrays <p3(nx,ny,nz)> gives the vertical coordinates, either
67
c     on the staggered or unstaggered grid (with <stagz> as the flag).
68
c     The surface pressure is given in <ps(nx,ny)>. If <fid> is negative, 
69
c     only the grid dimensions and grid parameters (xmin...pollat,nz) are 
70
c     determined and returned (this is needed for dynamical allocation of 
71
c     memory).
72
 
73
      use netcdf
74
 
75
      implicit none
76
 
77
c     Declaration of subroutine parameters 
78
      integer      fid                 ! File identifier
79
      real         xmin,xmax,ymin,ymax ! Domain size
80
      real         dx,dy               ! Horizontal resolution
81
      integer      nx,ny,nz            ! Grid dimensions
82
      real         pollon,pollat       ! Longitude and latitude of pole
83
      real         p3(nx,ny,nz)        ! Staggered levels
84
      real         ps(nx,ny)           ! Surface pressure
85
      real         time                ! Time of the grid information
86
      real         ak(nz),bk(nz)       ! Ak and Bk for layers or levels
87
      real         stagz               ! Vertical staggering (0 or -0.5)
88
      character*80 fieldname           ! Variable from which to take grid info
89
      character*80 timecheck           ! Either 'yes' or 'no'
90
 
91
c     Numerical and physical parameters
92
      real          eps                 ! Numerical epsilon
93
      parameter    (eps=0.001)
94
 
95
c     Netcdf variables
96
      integer      vardim(4)
97
      real         varmin(4),varmax(4)
98
      real         mdv
99
      real         stag(4)
100
      integer      ndim
101
      character*80 cstfile
102
      integer      cstid
103
      integer      nvars
104
      character*80 vars(100)
25 michaesp 105
      integer        dimids (nf90_max_var_dims),dimid
21 michaesp 106
      character*80   dimname(nf90_max_var_dims)
25 michaesp 107
      character*80   stdname
21 michaesp 108
      real,allocatable, dimension (:)     :: lon,lat,lev
109
      real,allocatable, dimension (:)     :: times
110
      real,allocatable, dimension (:,:)   :: tmp2
111
      real,allocatable, dimension (:,:,:) :: tmp3
23 michaesp 112
      real,allocatable, dimension (:)     :: aktmp,bktmp
21 michaesp 113
      character*80  units
25 michaesp 114
      character*80  leveltype
115
      integer       nakbktmp
116
      integer       vertical_swap
21 michaesp 117
 
118
c     Auxiliary variables
119
      integer      ierr       
120
      integer      i,j,k
121
      integer      isok
122
      real         tmp(200)
123
      character*80 varname
124
      real         rtime
125
      integer      varid
126
      integer      cdfid
127
      integer      stat
128
      real         delta
129
      integer      closear
130
      real         maxps,minps
131
 
25 michaesp 132
c     ---- Read data from netCDF file as they are ---------------------
133
 
134
c     Set file identifier
21 michaesp 135
      if (fid.lt.0) then
136
        cdfid = -fid
137
      else 
138
        cdfid = fid
139
      endif
140
 
141
c     Special handling if 3D pressure is
142
      if ( fieldname.eq.'P' ) then
143
         fieldname = 'U'
144
      endif
145
 
146
c     Get number of dimensions of variable -> ndim
147
      ierr = NF90_INQ_VARID(cdfid,fieldname,varid)
148
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
149
      ierr = nf90_inquire_variable(cdfid, varid, ndims  = ndim)
150
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
151
      if ( ndim.ne.4 ) then
152
          print*,' ERROR: netCDF variables need to be 4D'
153
          print*,'      ',trim(fieldname)
154
          stop
155
      endif
156
 
157
c     Get dimensions -> vardim(1:ndim),dimname(1:ndim)
158
      ierr = NF90_INQ_VARID(cdfid,fieldname,varid)
159
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
160
      ierr = nf90_inquire_variable(cdfid, varid, 
161
     >                                   dimids = dimids(1:ndim))
162
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
163
      do i=1,ndim
164
           ierr = nf90_inquire_dimension(cdfid, dimids(i), 
165
     >                               name = dimname(i) )
166
           IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
167
           ierr = nf90_inquire_dimension(cdfid, dimids(i),len=vardim(i))
168
           IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
169
      enddo
170
 
25 michaesp 171
c     Get dimension of AK,BK
172
      varname = 'nhym'
173
      ierr = NF90_INQ_DIMID(cdfid,varname,dimid)
174
      ierr = nf90_inquire_dimension(cdfid, dimid,len=nakbktmp)
175
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
176
 
21 michaesp 177
c     Check whether the list of dimensions is OK
178
      if ( ( dimname(1).ne.'lon'  ).or.
179
     >     ( dimname(2).ne.'lat'  ).or. 
180
     >     ( dimname(3).ne.'lev'  ).and.( dimname(3).ne.'lev_2'  ).or.
181
     >     ( dimname(4).ne.'time' ) )
182
     >then
183
        print*,' ERROR: the dimensions of the variable are not correct'
184
        print*,'        expected -> lon / lat / lev / time'
185
        print*, ( trim(dimname(i))//' / ',i=1,ndim )
186
        stop
187
      endif
188
 
25 michaesp 189
c     Check about the type of vertical levels
190
      varname=dimname(3)
191
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
192
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
193
      ierr = nf90_get_att(cdfid, varid, "standard_name", leveltype)
194
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
195
      if ( (leveltype.ne.'hybrid_sigma_pressure').and.
196
     >     (leveltype.ne.'air_pressure'         ) )
197
     >then
198
         print*,' ERROR: input netCDF data must be on hybrid-sigma'
199
         print*,'        or air pressure levels!',trim(leveltype)
200
         stop
201
      endif
202
 
21 michaesp 203
c     Allocate memory for reading arrays
204
      allocate(tmp2(vardim(1),vardim(2)),stat=stat)
205
      if (stat.ne.0) print*,'*** error allocating array tmp2     ***'
206
      allocate(tmp3(vardim(1),vardim(2),vardim(3)),stat=stat)
207
      if (stat.ne.0) print*,'*** error allocating array tmp3     ***'
208
      allocate(lon(vardim(1)),stat=stat)
209
      if (stat.ne.0) print*,'*** error allocating array lon     ***' 
210
      allocate(lat(vardim(2)),stat=stat)
211
      if (stat.ne.0) print*,'*** error allocating array lat     ***' 
25 michaesp 212
      allocate(lev(vardim(3)),stat=stat)
213
      if (stat.ne.0) print*,'*** error allocating array lev     ***'
21 michaesp 214
      allocate(times(vardim(4)),stat=stat)
215
      if (stat.ne.0) print*,'*** error allocating array times   ***'
25 michaesp 216
      allocate(aktmp(nakbktmp),stat=stat)
23 michaesp 217
      if (stat.ne.0) print*,'*** error allocating array aktmp   ***'
25 michaesp 218
      allocate(bktmp(nakbktmp),stat=stat)
23 michaesp 219
      if (stat.ne.0) print*,'*** error allocating array bktmp   ***'
21 michaesp 220
 
25 michaesp 221
c     Get domain longitudes, latitudes and levels
21 michaesp 222
      varname = dimname(1)
223
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
224
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
225
      ierr = nf90_get_var(cdfid,varid,lon)
226
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
227
      varname = dimname(2)
228
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
229
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
230
      ierr = nf90_get_var(cdfid,varid,lat)
231
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
25 michaesp 232
      varname = dimname(3)
233
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
234
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
235
      ierr = nf90_get_var(cdfid,varid,lev)
236
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
21 michaesp 237
 
238
c     Get ak and bk
239
      varname='hyam'
240
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
241
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
23 michaesp 242
      ierr = nf90_get_var(cdfid,varid,aktmp)
21 michaesp 243
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
244
      varname='hybm'
245
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
246
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
23 michaesp 247
      ierr = nf90_get_var(cdfid,varid,bktmp)
21 michaesp 248
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
249
 
250
c     Check that unit of ak is in hPa - if necessary correct it
251
      varname='hyam'
252
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
253
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
254
      ierr = nf90_get_att(cdfid, varid, "units", units)
255
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
256
      if ( units.eq.'Pa' ) then
25 michaesp 257
         do k=1,nakbktmp
23 michaesp 258
            aktmp(k) = 0.01 * aktmp(k)
21 michaesp 259
         enddo
260
      endif
261
 
25 michaesp 262
c     Check that unit of lev is in hPa - if necessary correct it
263
      if ( leveltype.eq.'air_pressure' ) then
264
         varname='lev'
265
         ierr = NF90_INQ_VARID(cdfid,varname,varid)
266
         IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
267
         ierr = nf90_get_att(cdfid, varid, "units", units)
268
         IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
269
         if ( units.eq.'Pa' ) then
270
            do k=1,vardim(3)
271
               lev(k) = 0.01 * lev(k)
272
            enddo
273
         endif
274
      endif
275
 
27 michaesp 276
c     Decide whether to swap vertical levels - highest pressure at index 1
25 michaesp 277
      vertical_swap = 1
278
      if ( leveltype.eq.'hybrid_sigma_pressure') then
279
        if ( (aktmp(1) + bktmp(1) * 1000.).gt.
280
     >       (aktmp(2) + bktmp(2) * 1000.) )
281
     >  then
282
          vertical_swap = 0
283
        endif
284
      elseif ( leveltype.eq.'air_pressure') then
285
        if ( lev(1).gt.lev(2) ) then
286
          vertical_swap = 0
287
        endif
288
      endif
289
c      print*,' Vertical SWAP P -> ', vertical_swap
290
 
21 michaesp 291
c     Get time information (check if time is correct)
292
      varname = 'time'
293
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
294
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
295
      ierr = nf90_get_var(cdfid,varid,times)
296
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
297
      isok=0
298
      do i=1,vardim(4)
299
        if (abs(time-times(i)).lt.eps) then
300
               isok = 1
301
               rtime = times(i)
302
        elseif (timecheck.eq.'no') then
303
               isok = 1
304
               rtime = times(1)
305
        endif
306
      enddo
307
      if ( isok.eq.0 ) then
308
         print*,' ERROR: time ',rtime,' not found on netCDF file' 
309
         stop
310
      endif
311
 
312
c     Read surface pressure
313
      varname='PS'
314
      ierr = NF90_INQ_VARID(cdfid,varname,varid)
315
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
316
      ierr = nf90_get_var(cdfid,varid,tmp2)
317
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
318
 
319
c     Check that surface pressure is in hPa
25 michaesp 320
      maxps = -1.e19
321
      minps =  1.e19
21 michaesp 322
      do i=1,vardim(1)
323
        do j=1,vardim(2)
324
             if (tmp2(i,j).gt.maxps) maxps = tmp2(i,j)
325
             if (tmp2(i,j).lt.minps) minps = tmp2(i,j)
326
        enddo
327
      enddo
328
      if ( (maxps.gt.1500.).or.(minps.lt.300.) ) then
329
         print*,' ERROR: surface pressre PS must be in hPa'
330
         print*,'       ',maxps,minps
331
         stop
332
      endif
333
 
25 michaesp 334
c     ---- Define output of subroutine --------------------------------
21 michaesp 335
 
27 michaesp 336
c     If not full list of vertical levels, reduce AK,BK arrays
337
      if ( (leveltype.eq.'hybrid_sigma_pressure').and.
338
     >     (nakbktmp.ne.vardim(3) ) )
339
     >then
33 michaesp 340
c         print*,' WARNING: only subset of vertical levels used...'
27 michaesp 341
         do k=1,vardim(3)
342
            if ( vertical_swap.eq.1 ) then
343
               aktmp(k) = aktmp( k+nakbktmp-vardim(3) )
344
               bktmp(k) = bktmp( k+nakbktmp-vardim(3) )
345
            endif
346
         enddo
347
      endif
348
 
21 michaesp 349
c     Set the grid dimensions and constants
350
      nx      = vardim(1)
351
      ny      = vardim(2)
352
      nz      = vardim(3)
353
      xmin    = lon(1)
354
      ymin    = lat(1)
355
      xmax    = lon(nx)
356
      ymax    = lat(ny)
357
      dx      = (xmax-xmin)/real(nx-1)
358
      dy      = (ymax-ymin)/real(ny-1)
359
      pollon  = 0.
360
      pollat  = 90.
361
      stagz   = 0.
362
      delta   = xmax-xmin-360.
363
      if (abs(delta+dx).lt.eps) then
364
          xmax    = xmax + dx
365
          nx      = nx + 1
366
          closear = 1
367
      else
368
          closear = 0
369
      endif
370
 
371
c     Save the output arrays (if fid>0) - close arrays on request
372
      if ( fid.gt.0 ) then
373
 
25 michaesp 374
c        Calculate layer pressures
375
         if (leveltype.eq.'hybrid_sigma_pressure' ) then
376
            do i=1,vardim(1)
377
              do j=1,vardim(2)
378
                 do k=1,vardim(3)
379
                  tmp3(i,j,k)=aktmp(k)+bktmp(k)*tmp2(i,j)
380
                 enddo
381
              enddo
382
           enddo
383
         elseif (leveltype.eq.'air_pressure' ) then
384
           do i=1,vardim(1)
385
              do j=1,vardim(2)
386
                 do k=1,vardim(3)
387
                  tmp3(i,j,k)=lev(k)
388
                 enddo
389
              enddo
390
           enddo
391
         endif
392
 
393
c        Get PS - close array on demand
21 michaesp 394
         do j=1,vardim(2)
395
           do i=1,vardim(1)
396
             ps(i,j) = tmp2(i,j)
397
           enddo
398
           if (closear.eq.1) ps(vardim(1)+1,j) = ps(1,j)
399
         enddo
400
 
25 michaesp 401
c        Get P3 - close array on demand + vertical swap
21 michaesp 402
         do j=1,vardim(2)
403
           do k=1,vardim(3)
404
             do i=1,vardim(1)
25 michaesp 405
               if ( vertical_swap.eq.1 ) then
406
                  p3(i,j,k) = tmp3(i,j,vardim(3)-k+1)
407
               else
408
                  p3(i,j,k) = tmp3(i,j,k)
409
               endif
21 michaesp 410
             enddo
411
             if (closear.eq.1) p3(vardim(1)+1,j,k) = p3(1,j,k)
412
           enddo
413
         enddo
23 michaesp 414
 
25 michaesp 415
c        Get AK,BK - vertical swap on demand
416
         if ( leveltype.eq.'hybrid_sigma_pressure' ) then
417
           do k=1,vardim(3)
418
              if ( vertical_swap.eq.1 ) then
419
                 ak(k) = aktmp(vardim(3)-k+1)
420
                 bk(k) = bktmp(vardim(3)-k+1)
31 michaesp 421
              else
422
                 ak(k) = aktmp(k)
423
                 bk(k) = bktmp(k)
25 michaesp 424
              endif
425
           enddo
426
         elseif (leveltype.eq.'air_pressure' ) then
427
           do k=1,vardim(3)
428
              if ( vertical_swap.eq.1 ) then
429
                 ak(k) = lev(vardim(3)-k+1)
430
                 bk(k) = 0.
431
              else
432
                ak(k) = lev(k)
433
                bk(k) = 0.
434
              endif
435
           enddo
436
         endif
23 michaesp 437
 
21 michaesp 438
      endif
439
 
25 michaesp 440
 
21 michaesp 441
      return
442
 
443
      end
444
 
445
c     ------------------------------------------------------------
446
c     Read wind information
447
c     ------------------------------------------------------------
448
 
449
      subroutine input_wind (fid,fieldname,field,time,stagz,mdv,
450
     >                       xmin,xmax,ymin,ymax,dx,dy,nx,ny,nz,
451
     >                       timecheck)
452
 
453
c     Read the wind component <fieldname> from the file with identifier
454
c     <fid> and save it in the 3d array <field>. The vertical staggering 
455
c     information is provided in <stagz> and gives the reference to either
456
c     the layer or level field from <input_grid>. A consistency check is
457
c     performed to have an agreement with the grid specified by <xmin,xmax,
458
c     ymin,ymax,dx,dy,nx,ny,nz>.
459
 
460
      use netcdf
461
 
462
      implicit none
463
 
464
c     Declaration of variables and parameters
465
      integer      fid                 ! File identifier
466
      character*80 fieldname           ! Name of the wind field
467
      integer      nx,ny,nz            ! Dimension of fields
468
      real         field(nx,ny,nz)     ! 3d wind field
469
      real         stagz               ! Staggering in the z direction
470
      real         mdv                 ! Missing data flag
471
      real         xmin,xmax,ymin,ymax ! Domain size
472
      real         dx,dy               ! Horizontal resolution
473
      real         time                ! Time
474
      character*80 timecheck           ! Either 'yes' or 'no'
475
 
476
c     Numerical and physical parameters
477
      real        eps                 ! Numerical epsilon
478
      parameter  (eps=0.001)
479
      real        notimecheck         ! 'Flag' for no time check
480
      parameter  (notimecheck=7.26537)
481
 
482
c     Netcdf variables
483
      integer      ierr
484
      character*80 varname
485
      integer      vardim(4)
486
      real         varmin(4),varmax(4)
487
      real         stag(4)
488
      integer      ndim
489
      real         times(10)
490
      integer      ntimes
491
      character*80 cstfile
492
      integer      cstid
493
      real         aklay(200),bklay(200),aklev(200),bklev(200)
494
      real         ps(nx,ny)
495
      integer      dimids (nf90_max_var_dims)
496
      character*80 dimname(nf90_max_var_dims)
497
      integer      varid
498
      integer      cdfid
25 michaesp 499
      real,allocatable, dimension (:)     :: lon,lat,lev
21 michaesp 500
      real,allocatable, dimension (:,:)   :: tmp2
501
      real,allocatable, dimension (:,:,:) :: tmp3
25 michaesp 502
      real,allocatable, dimension (:)     :: aktmp,bktmp
503
      character*80  leveltype
504
      integer       vertical_swap
505
      character*80  units
506
      integer       nakbktmp
507
      integer       dimid
21 michaesp 508
 
509
c     Auxiliary variables
510
      integer      isok
511
      integer      i,j,k
512
      integer      nz1
513
      real         rtime
514
      integer      closear
515
      integer      stat
516
      real         delta
36 michaesp 517
      integer      pressure
21 michaesp 518
 
29 michaesp 519
c     Init mdv
520
      mdv = -999.
36 michaesp 521
 
522
c     Special handling if 3D pressure is
523
      if ( fieldname.eq.'P' ) then
524
         fieldname = 'U'
525
         pressure  = 1
526
      else
527
         pressure = 0
528
      endif
29 michaesp 529
 
21 michaesp 530
c     Get the number of dimensions -> ndim
531
      ierr = NF90_INQ_VARID(fid,fieldname,varid)
532
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
533
      ierr = nf90_inquire_variable(fid, varid, ndims  = ndim)
534
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
535
 
536
c     Get the dimensions of the arrays -> varid(1:ndim)
537
      ierr = NF90_INQ_VARID(fid,fieldname,varid)
538
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
539
      ierr = nf90_inquire_variable(fid, varid, 
540
     >                                   dimids = dimids(1:ndim))
541
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
542
      do i=1,ndim
543
           ierr = nf90_inquire_dimension(fid, dimids(i), 
544
     >                               name = dimname(i) )
545
           IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
546
           ierr = nf90_inquire_dimension(fid, dimids(i),len=vardim(i))
547
           IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
548
      enddo
549
 
550
c     Check whether the list of dimensions is OK
551
      if ( ( dimname(1).ne.'lon'  ).or.
552
     >     ( dimname(2).ne.'lat'  ).or.
553
     >     ( dimname(3).ne.'lev'  ).and.( dimname(3).ne.'lev_2'  ).or.
554
     >     ( dimname(4).ne.'time' ) )
555
     >then
556
        print*,' ERROR: the dimensions of the variable are not correct'
557
        print*,'        expected -> lon / lat / lev / time'
558
        print*, ( trim(dimname(i))//' / ',i=1,ndim )
559
        stop
560
      endif
561
 
25 michaesp 562
c     Get dimension of AK,BK
563
      varname = 'nhym'
564
      ierr = NF90_INQ_DIMID(fid,varname,dimid)
565
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
566
      ierr = nf90_inquire_dimension(fid, dimid,len=nakbktmp)
567
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
568
 
569
c     Check about the type of vertical levels
570
      varname=dimname(3)
571
      ierr = NF90_INQ_VARID(fid,varname,varid)
572
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
573
      ierr = nf90_get_att(fid, varid, "standard_name", leveltype)
574
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
575
      if ( (leveltype.ne.'hybrid_sigma_pressure').and.
576
     >     (leveltype.ne.'air_pressure'         ) )
577
     >then
578
         print*,' ERROR: input netCDF data must be on hybrid-sigma'
579
         print*,'        or air pressure levels!',trim(leveltype)
580
         stop
581
      endif
582
 
21 michaesp 583
c     Allocate memory for reading arrays - depending on <closear>
584
      allocate(tmp2(vardim(1),vardim(2)),stat=stat)
585
      if (stat.ne.0) print*,'*** error allocating array tmp2     ***'
586
      allocate(tmp3(vardim(1),vardim(2),vardim(3)),stat=stat)
587
      if (stat.ne.0) print*,'*** error allocating array tmp3     ***'
588
      allocate(lon(vardim(1)),stat=stat)
589
      if (stat.ne.0) print*,'*** error allocating array lon     ***'
590
      allocate(lat(vardim(2)),stat=stat)
591
      if (stat.ne.0) print*,'*** error allocating array lat     ***'
25 michaesp 592
      allocate(lev(vardim(3)),stat=stat)
593
      if (stat.ne.0) print*,'*** error allocating array lev     ***'
594
      allocate(aktmp(nakbktmp),stat=stat)
595
      if (stat.ne.0) print*,'*** error allocating array aktmp   ***'
596
      allocate(bktmp(nakbktmp),stat=stat)
597
      if (stat.ne.0) print*,'*** error allocating array bktmp   ***'
21 michaesp 598
 
25 michaesp 599
c     Get domain boundaries - longitude, latitude, levels
21 michaesp 600
      varname = dimname(1)
601
      ierr = NF90_INQ_VARID(fid,varname,varid)
602
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
603
      ierr = nf90_get_var(fid,varid,lon)
604
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
605
      varname = dimname(2)
606
      ierr = NF90_INQ_VARID(fid,varname,varid)
607
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
608
      ierr = nf90_get_var(fid,varid,lat)
609
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
25 michaesp 610
      varname = dimname(3)
611
      ierr = NF90_INQ_VARID(fid,varname,varid)
612
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
613
      ierr = nf90_get_var(fid,varid,lev)
614
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
31 michaesp 615
      varmin(1) = lon(1)
616
      varmax(1) = lon( vardim(1) )
617
      varmin(2) = lat(1)
618
      varmax(2) = lat( vardim(2) )
21 michaesp 619
 
25 michaesp 620
c     Get ak and bk
621
      varname='hyam'
622
      ierr = NF90_INQ_VARID(fid,varname,varid)
623
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
624
      ierr = nf90_get_var(fid,varid,aktmp)
625
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
626
      varname='hybm'
627
      ierr = NF90_INQ_VARID(fid,varname,varid)
628
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
629
      ierr = nf90_get_var(fid,varid,bktmp)
630
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
631
 
632
c     Check that unit of ak is in hPa - if necessary correct it
633
      varname='hyam'
634
      ierr = NF90_INQ_VARID(fid,varname,varid)
635
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
636
      ierr = nf90_get_att(fid, varid, "units", units)
637
      IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
638
      if ( units.eq.'Pa' ) then
639
         do k=1,nakbktmp
640
            aktmp(k) = 0.01 * aktmp(k)
641
         enddo
642
      endif
643
 
644
c     Check that unit of lev is in hPa - if necessary correct it
645
      if ( leveltype.eq.'air_pressure' ) then
646
         varname='lev'
647
         ierr = NF90_INQ_VARID(fid,varname,varid)
648
         IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
649
         ierr = nf90_get_att(fid, varid, "units", units)
650
         IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
651
         if ( units.eq.'Pa' ) then
652
            do k=1,vardim(3)
653
               lev(k) = 0.01 * lev(k)
654
            enddo
655
         endif
656
      endif
657
 
658
c     Decide whether to swap vertical levels
659
      vertical_swap = 1
660
      if ( leveltype.eq.'hybrid_sigma_pressure') then
661
        if ( (aktmp(1) + bktmp(1) * 1000.).gt.
662
     >       (aktmp(2) + bktmp(2) * 1000.) )
663
     >  then
664
          vertical_swap = 0
665
        endif
666
      elseif ( leveltype.eq.'air_pressure') then
667
        if ( lev(1).gt.lev(2) ) then
668
          vertical_swap = 0
669
        endif
29 michaesp 670
      endif
25 michaesp 671
 
36 michaesp 672
c     Read data /or set 3D pressure field) 
673
      if ( pressure.eq.0 ) then
674
         ierr = NF90_INQ_VARID(fid,fieldname,varid)
675
         IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
676
         ierr = nf90_get_var(fid,varid,tmp3)
677
         IF(ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
678
      else
679
         if (leveltype.eq.'hybrid_sigma_pressure' ) then
680
            do i=1,vardim(1)
681
              do j=1,vardim(2)
682
                 do k=1,vardim(3)
683
                  tmp3(i,j,k)=aktmp(k)+bktmp(k)*tmp2(i,j)
684
                 enddo
685
              enddo
686
           enddo
687
         elseif (leveltype.eq.'air_pressure' ) then
688
           do i=1,vardim(1)
689
              do j=1,vardim(2)
690
                 do k=1,vardim(3)
691
                  tmp3(i,j,k)=lev(k)
692
                 enddo
693
              enddo
694
           enddo
695
         endif
696
      endif
21 michaesp 697
 
698
c     If the field is 2D, expand it to 3D - simple handling of 2D tracing
699
      if ( vardim(3).eq.1 ) then
700
         do i=1,vardim(1)
701
            do j=1,vardim(2)
702
               do k=1,vardim(3)
703
                  tmp3(i,j,k) = tmp3(i,j,1)
704
               enddo
705
            enddo
706
         enddo
707
      endif
708
 
25 michaesp 709
c     Decide whether to close arrays
21 michaesp 710
      delta = varmax(1)-varmin(1)-360.
711
      if (abs(delta+dx).lt.eps) then
712
          closear = 1
713
      else
714
          closear = 0
715
      endif
716
 
25 michaesp 717
c     Save output array - close array and swap on demand
21 michaesp 718
      do j=1,vardim(2)
719
        do k=1,vardim(3)
720
          do i=1,vardim(1)
25 michaesp 721
             if ( vertical_swap.eq.1 ) then
722
                 field(i,j,k) = tmp3(i,j,vardim(3)-k+1)
723
             else
724
                 field(i,j,k) = tmp3(i,j,k)
725
             endif
21 michaesp 726
          enddo
727
          if (closear.eq.1) field(vardim(1)+1,j,k) = field(1,j,k)
728
        enddo
729
      enddo
730
 
731
c     Exit point
732
      return
733
 
734
      end
735
 
736
c     ------------------------------------------------------------
737
c     Close input file
738
c     ------------------------------------------------------------
739
 
740
      subroutine input_close(fid)
741
 
742
c     Close the input file with file identifier <fid>.
743
 
744
      use netcdf
745
 
746
      implicit none
747
 
748
c     Declaration of subroutine parameters
749
      integer fid
750
 
751
c     Auxiliary variables
752
      integer ierr
753
 
754
c     Close file
755
      ierr = NF90_CLOSE(fid)
756
      IF( ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
757
 
758
      end
759
 
760
c     ------------------------------------------------------------
761
c     Get a list of variables on netCDF file
762
c     ------------------------------------------------------------
763
 
764
      subroutine input_getvars(fid,vnam,nvars)
765
 
766
c     List of variables on netCDF file
767
 
768
      use netcdf
769
 
770
      implicit none
771
 
772
c     Declaration of subroutine parameters
773
      integer      fid
774
      integer      nvars
775
      character*80 vnam(200)
776
 
777
c     Auxiliary variables
778
      integer ierr
779
      integer i
780
      integer nDims,nGlobalAtts,unlimdimid
781
 
782
      ierr = nf90_inquire(fid, nDims, nVars, nGlobalAtts, unlimdimid)
783
      IF( ierr /= nf90_NoErr) PRINT *,NF90_STRERROR(ierr)
784
 
785
      do i=1,nVars
786
         ierr = nf90_inquire_variable(fid, i, name = vnam(i))
787
      enddo
788
 
789
      end