atm_split.c

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/*
  This file is part of MPTRAC.
  
  MPTRAC 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.
  
  MPTRAC 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 MPTRAC. If not, see <http://www.gnu.org/licenses/>.
  
  Copyright (C) 2013-2026 Forschungszentrum Juelich GmbH
*/
 
#include "mptrac.h"
 
/* ------------------------------------------------------------
   Functions...
   ------------------------------------------------------------ */
 
void usage(
  void);
 
/* ------------------------------------------------------------
   Main...
   ------------------------------------------------------------ */
 
int main(
  int argc,
  char *argv[]) {
 
  atm_t *atm, *atm2;
 
  ctl_t ctl;
 
  char kernel[LEN];
 
  double k, kw[EP], kz[EP], mmax = 0, mtot = 0, z, zmin = 0, zmax = 0;
 
  int ip, nk = 0;
 
  /* Allocate... */
  ALLOC(atm, atm_t, 1);
  ALLOC(atm2, atm_t, 1);
 
  /* Print usage information... */
  USAGE;
 
  /* Check arguments... */
  if (argc < 4)
    ERRMSG("Missing or invalid command-line arguments.\n\n"
           "Usage: atm_split <ctl> <atm_in> <atm_out> [KEY VALUE ...]\n\n"
           "Use -h for full help.");
 
  /* Read control parameters... */
  mptrac_read_ctl(argv[1], argc, argv, &ctl);
  const int n = (int) scan_ctl(argv[1], argc, argv, "SPLIT_N", -1, "", NULL);
  const double m = scan_ctl(argv[1], argc, argv, "SPLIT_M", -1, "-999", NULL);
  const double um = scan_ctl(argv[1], argc, argv, "SPLIT_UM", -1, "0", NULL);
  const double dt = scan_ctl(argv[1], argc, argv, "SPLIT_DT", -1, "0", NULL);
  const double t0 = scan_ctl(argv[1], argc, argv, "SPLIT_T0", -1, "0", NULL);
  const double t1 = scan_ctl(argv[1], argc, argv, "SPLIT_T1", -1, "0", NULL);
  const double dz = scan_ctl(argv[1], argc, argv, "SPLIT_DZ", -1, "0", NULL);
  const double z0 = scan_ctl(argv[1], argc, argv, "SPLIT_Z0", -1, "0", NULL);
  const double z1 = scan_ctl(argv[1], argc, argv, "SPLIT_Z1", -1, "0", NULL);
  const double dx = scan_ctl(argv[1], argc, argv, "SPLIT_DX", -1, "0", NULL);
  const double lon0 =
    scan_ctl(argv[1], argc, argv, "SPLIT_LON0", -1, "0", NULL);
  const double lon1 =
    scan_ctl(argv[1], argc, argv, "SPLIT_LON1", -1, "0", NULL);
  const double lat0 =
    scan_ctl(argv[1], argc, argv, "SPLIT_LAT0", -1, "0", NULL);
  const double lat1 =
    scan_ctl(argv[1], argc, argv, "SPLIT_LAT1", -1, "0", NULL);
  scan_ctl(argv[1], argc, argv, "SPLIT_KERNEL", -1, "-", kernel);
 
  /* Init random number generator... */
  gsl_rng_env_setup();
  gsl_rng *rng = gsl_rng_alloc(gsl_rng_default);
 
  /* Read atmospheric data... */
  if (!mptrac_read_atm(argv[2], &ctl, atm))
    ERRMSG("Cannot open file!");
 
  /* Read kernel function... */
  if (kernel[0] != '-') {
    read_kernel(kernel, kz, kw, &nk);
    zmax = gsl_stats_max(kz, 1, (size_t) nk);
    zmin = gsl_stats_min(kz, 1, (size_t) nk);
  }
 
  /* Get total and maximum mass... */
  if (ctl.qnt_m >= 0)
    for (ip = 0; ip < atm->np; ip++) {
      mtot += atm->q[ctl.qnt_m][ip];
      mmax = MAX(mmax, atm->q[ctl.qnt_m][ip]);
    }
  if (m >= 0)
    mtot = m;
 
  /* Loop over air parcels... */
  for (int i = 0; i < n; i++) {
 
    /* Select air parcel... */
    if (ctl.qnt_m >= 0)
      do {
        ip = (int) gsl_rng_uniform_int(rng, (long unsigned int) atm->np);
      } while (gsl_rng_uniform(rng) > atm->q[ctl.qnt_m][ip] / mmax);
    else
      ip = (int) gsl_rng_uniform_int(rng, (long unsigned int) atm->np);
 
    /* Set time... */
    if (t1 > t0)
      atm2->time[atm2->np] = t0 + (t1 - t0) * gsl_rng_uniform_pos(rng);
    else
      atm2->time[atm2->np] = atm->time[ip]
        + gsl_ran_gaussian_ziggurat(rng, dt / 2.3548);
 
    /* Set vertical position... */
    do {
      if (nk > 0) {
        do {
          z = zmin + (zmax - zmin) * gsl_rng_uniform_pos(rng);
          k = kernel_weight(kz, kw, nk, P(z));
        } while (gsl_rng_uniform(rng) > k);
        atm2->p[atm2->np] = P(z);
      } else if (z1 > z0)
        atm2->p[atm2->np] = P(z0 + (z1 - z0) * gsl_rng_uniform_pos(rng));
      else
        atm2->p[atm2->np] = atm->p[ip]
          + DZ2DP(gsl_ran_gaussian_ziggurat(rng, dz / 2.3548), atm->p[ip]);
    } while (atm2->p[atm2->np] < P(100.) || atm2->p[atm2->np] > P(-1.));
 
    /* Set horizontal position... */
    if (lon1 > lon0 && lat1 > lat0) {
      atm2->lon[atm2->np] = lon0 + (lon1 - lon0) * gsl_rng_uniform_pos(rng);
      atm2->lat[atm2->np] = lat0 + (lat1 - lat0) * gsl_rng_uniform_pos(rng);
    } else {
      atm2->lon[atm2->np] = atm->lon[ip]
        + gsl_ran_gaussian_ziggurat(rng, DX2DEG(dx, atm->lat[ip]) / 2.3548);
      atm2->lat[atm2->np] = atm->lat[ip]
        + gsl_ran_gaussian_ziggurat(rng, DY2DEG(dx) / 2.3548);
    }
 
    /* Copy quantities... */
    for (int iq = 0; iq < ctl.nq; iq++)
      atm2->q[iq][atm2->np] = atm->q[iq][ip];
 
    /* Adjust mass... */
    if (ctl.qnt_m >= 0)
      atm2->q[ctl.qnt_m][atm2->np]
        = (mtot + (um > 0 ? um * (gsl_rng_uniform_pos(rng) - 0.5) : 0.0)) / n;
 
    /* Adjust air parcel index... */
    if (ctl.qnt_idx >= 0)
      atm2->q[ctl.qnt_idx][atm2->np] = atm2->np;
 
    /* Increment particle counter... */
    if ((++atm2->np) > NP)
      ERRMSG("Too many air parcels!");
  }
 
  /* Save data and close file... */
  mptrac_write_atm(argv[3], &ctl, atm2, 0);
 
  /* Free... */
  free(atm);
  free(atm2);
 
  return EXIT_SUCCESS;
}
 
/*****************************************************************************/
 
void usage(
  void) {
 
  printf("\nMPTRAC atm_split tool.\n\n");
  printf("Split air parcels into a larger number of parcels.\n");
  printf("\n");
  printf("Usage:\n");
  printf("  atm_split <ctl> <atm_in> <atm_out> [KEY VALUE ...]\n");
  printf("\n");
  printf("Arguments:\n");
  printf("  <ctl>      Control file.\n");
  printf("  <atm_in>   Atmospheric input file.\n");
  printf("  <atm_out>  Atmospheric output file.\n");
  printf("  [KEY VALUE]  Optional control parameters.\n");
  printf("\nFurther information:\n");
  printf("  Manual: https://slcs-jsc.github.io/mptrac/\n");
}