refraction.cc

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/* Copyright (C) 2002-2012 Patrick Eriksson <patrick.eriksson@chalmers.se>
 
   This program 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 2, or (at your option) any
   later version.
 
   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
   USA. */
 
 
 
/*===========================================================================
  === File description
  ===========================================================================*/
 
/*===========================================================================
  === External declarations
  ===========================================================================*/
 
#include <cmath>
#include "auto_md.h"
#include "complex.h"          
#include "interpolation.h"
#include "geodetic.h"
#include "refraction.h"
#include "special_interp.h"
 
extern const Numeric DEG2RAD;
extern const Numeric RAD2DEG;
extern const Numeric TEMP_0_C;
 
 
 
/*===========================================================================
  === The functions (in alphabetical order)
  ===========================================================================*/
 
 
 
void complex_n_water_liebe93(
         Matrix&   complex_n,
   const Vector&   f_grid,
   const Numeric&  t )
{
  chk_if_in_range( "t", t, TEMP_0_C-40, TEMP_0_C+100 );
  chk_if_in_range( "min of f_grid", min(f_grid), 10e9, 1000e9 );
  chk_if_in_range( "max of f_grid", max(f_grid), 10e9, 1000e9 );
 
  const Index   nf = f_grid.nelem();
 
  complex_n.resize( nf, 2 );
 
  // Implementation following epswater93.m (by C. Mätzler), part of Atmlab,
  // but numeric values strictly following the paper version (146, not 146.4)
  const Numeric   theta = 1 - 300 / t;
  const Numeric   e0    = 77.66 - 103.3 * theta;
  const Numeric   e1    = 0.0671 * e0;
  const Numeric   f1    = 20.2 + 146 * theta + 316 * theta * theta;
  const Numeric   e2    = 3.52;  
  const Numeric   f2    = 39.8 * f1;
 
  for( Index iv=0; iv<nf; iv++ )
    { 
      const Complex  ifGHz( 0.0, f_grid[iv]/1e9 );
          
      Complex n = sqrt( e2 + (e1-e2) / (Numeric(1.0)-ifGHz/f2) + 
                             (e0-e1) / (Numeric(1.0)-ifGHz/f1) );
    
      complex_n(iv,0) = n.real();
      complex_n(iv,1) = n.imag();
    }
}
 
 
 
 
void get_refr_index_1d(
          Workspace&  ws,
          Numeric&    refr_index_air,
          Numeric&    refr_index_air_group,
    const Agenda&     refr_index_air_agenda,
    ConstVectorView   p_grid,
    ConstVectorView   refellipsoid,
    ConstTensor3View  z_field,
    ConstTensor3View  t_field,
    ConstTensor4View  vmr_field,
    ConstVectorView   f_grid,
    const Numeric&    r )
{ 
  Numeric   rtp_pressure, rtp_temperature;
  Vector    rtp_vmr;
 
  // Pressure grid position
  ArrayOfGridPos   gp(1);
  gridpos( gp, z_field(joker,0,0), Vector( 1, r - refellipsoid[0] ) );
 
  // Altitude interpolation weights
  Matrix   itw(1,2);
  interpweights( itw, gp );
 
  // Pressure
  Vector   dummy(1);
  itw2p( dummy, p_grid, gp, itw );
  rtp_pressure = dummy[0];
 
  // Temperature
  interp( dummy, itw, t_field(joker,0,0), gp );
  rtp_temperature = dummy[0];
 
  // VMR
  const Index   ns = vmr_field.nbooks();
  //
  rtp_vmr.resize(ns);
  //
  for( Index is=0; is<ns; is++ )
    {
      interp( dummy, itw, vmr_field(is,joker,0,0), gp );
      rtp_vmr[is] = dummy[0];
    }
 
  refr_index_air_agendaExecute( ws, refr_index_air, refr_index_air_group, 
                            rtp_pressure, rtp_temperature, rtp_vmr, 
                            f_grid, refr_index_air_agenda );
}
 
 
 
 
void get_refr_index_2d(
          Workspace&  ws,
          Numeric&    refr_index_air,
          Numeric&    refr_index_air_group,
    const Agenda&     refr_index_air_agenda,
    ConstVectorView   p_grid,
    ConstVectorView   lat_grid,
    ConstVectorView   refellipsoid,
    ConstTensor3View  z_field,
    ConstTensor3View  t_field,
    ConstTensor4View  vmr_field,
    ConstVectorView   f_grid,
    const Numeric&    r,
    const Numeric&    lat )
{ 
  Numeric   rtp_pressure, rtp_temperature;
  Vector    rtp_vmr;
 
  // Determine the geometric altitudes at *lat*
  const Index      np = p_grid.nelem();
  Vector           z_grid(np);
  ArrayOfGridPos   gp_lat(1);
  //
  gridpos( gp_lat, lat_grid, lat );
  z_at_lat_2d( z_grid, p_grid, lat_grid, z_field(joker,joker,0), gp_lat[0] );
 
  // Determine the ellipsoid radius at *lat*
  const Numeric   rellips = refell2d( refellipsoid, lat_grid, gp_lat[0] );
 
  // Altitude (equal to pressure) grid position
  ArrayOfGridPos   gp_p(1);
  gridpos( gp_p, z_grid, Vector( 1, r - rellips ) );
 
  // Altitude interpolation weights
  Matrix   itw(1,2);
  Vector   dummy(1);
  interpweights( itw, gp_p );
 
  // Pressure
  itw2p( dummy, p_grid, gp_p, itw );
  rtp_pressure = dummy[0];
 
  // Temperature
  itw.resize(1,4);
  interpweights( itw, gp_p, gp_lat );
  interp( dummy, itw, t_field(joker,joker,0), gp_p, gp_lat );
  rtp_temperature = dummy[0];
 
  // VMR
  const Index   ns = vmr_field.nbooks();
  //
  rtp_vmr.resize(ns);
  //
  for( Index is=0; is<ns; is++ )
    {
      interp( dummy, itw, vmr_field(is,joker,joker,0), gp_p, gp_lat );
      rtp_vmr[is] = dummy[0];
    }
 
 
  refr_index_air_agendaExecute( ws, refr_index_air, refr_index_air_group, 
                            rtp_pressure, rtp_temperature, rtp_vmr, 
                            f_grid, refr_index_air_agenda );
}
 
 
 
void get_refr_index_3d(
          Workspace&  ws,
          Numeric&    refr_index_air,
          Numeric&    refr_index_air_group,
    const Agenda&     refr_index_air_agenda,
    ConstVectorView   p_grid,
    ConstVectorView   lat_grid,
    ConstVectorView   lon_grid,
    ConstVectorView   refellipsoid,
    ConstTensor3View  z_field,
    ConstTensor3View  t_field,
    ConstTensor4View  vmr_field,
    ConstVectorView   f_grid,
    const Numeric&    r,
    const Numeric&    lat,
    const Numeric&    lon )
{ 
  Numeric   rtp_pressure, rtp_temperature;
  Vector    rtp_vmr;
 
  // Determine the geometric altitudes at *lat* and *lon*
  const Index      np = p_grid.nelem();
  Vector           z_grid(np);
  ArrayOfGridPos   gp_lat(1), gp_lon(1);
  //
  gridpos( gp_lat, lat_grid, lat );
  gridpos( gp_lon, lon_grid, lon );
  z_at_latlon( z_grid, p_grid, lat_grid, lon_grid, z_field, 
                                                        gp_lat[0], gp_lon[0] );
  
  // Determine the elipsoid radius at *lat*
  const Numeric   rellips = refell2d( refellipsoid, lat_grid, gp_lat[0] );
 
  // Altitude (equal to pressure) grid position
  ArrayOfGridPos   gp_p(1);
  gridpos( gp_p, z_grid, Vector( 1, r - rellips ) );
 
  // Altitude interpolation weights
  Matrix   itw(1,2);
  Vector   dummy(1);
  interpweights( itw, gp_p );
 
  // Pressure
  itw2p( dummy, p_grid, gp_p, itw );
  rtp_pressure = dummy[0];
 
  // Temperature
  itw.resize(1,8);
  interpweights( itw, gp_p, gp_lat, gp_lon );
  interp( dummy, itw, t_field, gp_p, gp_lat, gp_lon );
  rtp_temperature = dummy[0];
 
  // VMR
  const Index   ns = vmr_field.nbooks();
  //
  rtp_vmr.resize(ns);
  //
  for( Index is=0; is<ns; is++ )
    {
      interp( dummy, itw, vmr_field(is,joker,joker,joker), gp_p, gp_lat, 
                                                                      gp_lon );
      rtp_vmr[is] = dummy[0];
    }
 
  refr_index_air_agendaExecute( ws, refr_index_air, refr_index_air_group, 
                            rtp_pressure, rtp_temperature, rtp_vmr, 
                            f_grid, refr_index_air_agenda );
}
 
 
 
 
void refr_gradients_1d(
          Workspace&  ws,
          Numeric&    refr_index_air,
          Numeric&    refr_index_air_group,
          Numeric&    dndr,
    const Agenda&     refr_index_air_agenda,
    ConstVectorView   p_grid,
    ConstVectorView   refellipsoid,
    ConstTensor3View  z_field,
    ConstTensor3View  t_field,
    ConstTensor4View  vmr_field,
    ConstVectorView   f_grid,
    const Numeric&    r )
{ 
  get_refr_index_1d( ws, refr_index_air, refr_index_air_group, 
                     refr_index_air_agenda, p_grid, refellipsoid, 
                     z_field, t_field, vmr_field, f_grid, r );
 
  const Numeric   n0 = refr_index_air;
        Numeric   dummy;
 
  get_refr_index_1d( ws, refr_index_air, dummy, 
                     refr_index_air_agenda, p_grid, refellipsoid, 
                     z_field, t_field, vmr_field, f_grid, r+1 );
 
  dndr = refr_index_air - n0;
 
  refr_index_air = n0;
}
 
 
 
 
void refr_gradients_2d(
          Workspace&  ws,
          Numeric&    refr_index_air,
          Numeric&    refr_index_air_group,
          Numeric&    dndr,
          Numeric&    dndlat,
    const Agenda&     refr_index_air_agenda,
    ConstVectorView   p_grid,
    ConstVectorView   lat_grid,
    ConstVectorView   refellipsoid,
    ConstTensor3View  z_field,
    ConstTensor3View  t_field,
    ConstTensor4View  vmr_field,
    ConstVectorView   f_grid,
    const Numeric&    r,
    const Numeric&    lat )
{ 
  get_refr_index_2d( ws, refr_index_air, refr_index_air_group, 
                     refr_index_air_agenda, p_grid, lat_grid, refellipsoid, 
                     z_field, t_field, vmr_field, f_grid, r, lat );
 
  const Numeric   n0 = refr_index_air;
        Numeric   dummy;
 
  get_refr_index_2d( ws, refr_index_air, dummy, refr_index_air_agenda, p_grid, 
                     lat_grid, refellipsoid, z_field, t_field, vmr_field, 
                     f_grid, r+1, lat );
 
  dndr = refr_index_air - n0;
 
  const Numeric   dlat = 1e-4;
 
  get_refr_index_2d( ws, refr_index_air, dummy, refr_index_air_agenda, p_grid, 
                     lat_grid, refellipsoid, z_field, t_field, vmr_field, 
                     f_grid, r, lat+dlat );
 
  dndlat = ( refr_index_air - n0 ) / ( DEG2RAD * dlat * r ); 
 
  refr_index_air = n0;
}
 
 
 
 
void refr_gradients_3d(
          Workspace&  ws,
          Numeric&    refr_index_air,
          Numeric&    refr_index_air_group,
          Numeric&    dndr,
          Numeric&    dndlat,
          Numeric&    dndlon,
    const Agenda&     refr_index_air_agenda,
    ConstVectorView   p_grid,
    ConstVectorView   lat_grid,
    ConstVectorView   lon_grid,
    ConstVectorView   refellipsoid,
    ConstTensor3View  z_field,
    ConstTensor3View  t_field,
    ConstTensor4View  vmr_field,
    ConstVectorView   f_grid,
    const Numeric&    r,
    const Numeric&    lat,
    const Numeric&    lon )
{ 
  get_refr_index_3d( ws, refr_index_air, refr_index_air_group, 
                     refr_index_air_agenda, p_grid, lat_grid, lon_grid, 
                     refellipsoid, z_field, t_field, vmr_field, f_grid, 
                     r, lat, lon );
 
  const Numeric   n0 = refr_index_air;
        Numeric   dummy;
 
  get_refr_index_3d( ws, refr_index_air, dummy, refr_index_air_agenda, p_grid, 
                     lat_grid, lon_grid, refellipsoid, z_field, t_field, 
                     vmr_field, f_grid, r+1, lat, lon );
 
  dndr = refr_index_air - n0;
 
  const Numeric   dlat = 1e-4;
 
  get_refr_index_3d( ws, refr_index_air, dummy, refr_index_air_agenda, p_grid, 
                     lat_grid, lon_grid, refellipsoid, z_field, t_field, 
                     vmr_field, f_grid, r, lat+dlat, lon );
 
  dndlat = ( refr_index_air - n0 ) / ( DEG2RAD * dlat * r ); 
 
  const Numeric   dlon = 1e-4;
 
  get_refr_index_3d( ws, refr_index_air, dummy, refr_index_air_agenda, p_grid, 
                     lat_grid, lon_grid, refellipsoid, z_field, t_field, 
                     vmr_field, f_grid, r, lat, lon+dlon);
 
  dndlon = ( refr_index_air - n0 ) / 
           ( DEG2RAD * dlon * r * cos( DEG2RAD*lat ) ); 
  
  refr_index_air = n0;
}