bands.c

Go to the documentation of this file.

/*
  This file is part of the IASI Code Collection.
  
  the IASI Code Collections is free software: you can redistribute it
  and/or modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation, either version 3 of
  the License, or (at your option) any later version.
  
  The IASI Code Collection is distributed in the hope that it will be
  useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with the IASI Code Collection. If not, see
  <http://www.gnu.org/licenses/>.
  
  Copyright (C) 2019-2026 Forschungszentrum Juelich GmbH
*/
 
#include "libiasi.h"
 
/* ------------------------------------------------------------
   Dimensions...
   ------------------------------------------------------------ */
 
/* Maximum number of bands... */
#define NB 100
 
/* ------------------------------------------------------------
   Main...
   ------------------------------------------------------------ */
 
int main(
  int argc,
  char *argv[]) {
 
  static iasi_rad_t *iasi_rad;
 
  static FILE *out;
 
  static double numin[NB], numax[NB], rad[NB];
 
  static int iarg, ib, ichan, n, nb, track, xtrack, format;
 
  /* Check arguments... */
  if (argc < 4)
    ERRMSG("Give parameters: <ctl> <out.tab> <l1b_file1> [<l1b_file2> ...]");
 
  /* Allocate... */
  ALLOC(iasi_rad, iasi_rad_t, 1);
 
  /* Get control parameters... */
  nb = (int) scan_ctl(argc, argv, "NB", -1, "1", NULL);
  if (nb > NB)
    ERRMSG("Too many bands!");
  for (ib = 0; ib < nb; ib++) {
    numin[ib] = scan_ctl(argc, argv, "NUMIN", ib, "", NULL);
    numax[ib] = scan_ctl(argc, argv, "NUMAX", ib, "", NULL);
  }
  format = (int) scan_ctl(argc, argv, "FORMAT", -1, "1", NULL);
 
  /* Create file... */
  printf("Write band data: %s\n", argv[2]);
  if (!(out = fopen(argv[2], "w")))
    ERRMSG("Cannot create file!");
 
  /* Loop over IASI files... */
  for (iarg = 3; iarg < argc; iarg++) {
 
    /* Read IASI data... */
    printf("Read IASI Level-1C data file: %s\n", argv[iarg]);
    iasi_read(format, argv[iarg], iasi_rad);
 
    /* Write header... */
    if (iarg == 3) {
      fprintf(out,
              "# $1 = time [s]\n"
              "# $2 = footprint longitude [deg]\n"
              "# $3 = footprint latitude [deg]\n"
              "# $4 = satellite altitude [km]\n"
              "# $5 = satellite longitude [deg]\n"
              "# $6 = satellite latitude [deg]\n");
      for (ib = 0; ib < nb; ib++)
        fprintf(out,
                "# $%d = BT(%.2f/cm...%.2f/cm) [K]\n",
                7 + ib, numin[ib], numax[ib]);
    }
 
    /* Loop over scans... */
    for (track = 0; track < iasi_rad->ntrack; track++) {
 
      /* Write output... */
      fprintf(out, "\n");
 
      /* Loop over footprints... */
      for (xtrack = 0; xtrack < L1_NXTRACK; xtrack++) {
 
        /* Write output... */
        fprintf(out, "%.2f %.4f %.4f %.3f %.4f %.4f",
                iasi_rad->Time[track][xtrack],
                iasi_rad->Longitude[track][xtrack],
                iasi_rad->Latitude[track][xtrack],
                iasi_rad->Sat_z[track],
                iasi_rad->Sat_lon[track], iasi_rad->Sat_lat[track]);
 
        /* Loop over bands... */
        for (ib = 0; ib < nb; ib++) {
 
          /* Get mean radiance... */
          n = 0;
          rad[ib] = 0;
          for (ichan = 0; ichan <= IASI_L1_NCHAN; ichan++)
            if (iasi_rad->freq[ichan] >= numin[ib]
                && iasi_rad->freq[ichan] <= numax[ib]
                && gsl_finite(iasi_rad->Rad[track][xtrack][ichan])) {
              rad[ib] += iasi_rad->Rad[track][xtrack][ichan];
              n++;
            }
          if (n > 0)
            rad[ib] /= n;
          else
            rad[ib] = GSL_NAN;
 
          /* Convert to brightness temperature... */
          rad[ib] = BRIGHT(rad[ib], 0.5 * (numin[ib] + numax[ib]));
 
          /* Write output... */
          fprintf(out, " %.3f", rad[ib]);
        }
 
        /* Write output... */
        fprintf(out, "\n");
      }
    }
  }
 
  /* Close file... */
  fclose(out);
 
  /* Free... */
  free(iasi_rad);
 
  return EXIT_SUCCESS;
}