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    "# Calculating Weighting Functions with HR\n",
    "\n",
    "In this example we calculate weighting functions for ozone in a one-dimensional atmosphere using the HR model.  "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "%matplotlib inline"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import sasktran as sk\n",
    "import matplotlib.pyplot as plt\n",
    "import numpy as np\n",
    "from sasktran.geometry import VerticalImage\n",
    "\n",
    "tanalts_km = np.arange(10, 50, 1)\n",
    "\n",
    "# First recreate our geometry and atmosphere classes\n",
    "geometry = VerticalImage()\n",
    "geometry.from_sza_saa(sza=60, saa=60, lat=0, lon=0, tanalts_km=tanalts_km, mjd=54372, locallook=0,\n",
    "                      satalt_km=600, refalt_km=20)\n",
    "\n",
    "atmosphere = sk.Atmosphere()\n",
    "\n",
    "atmosphere['ozone'] = sk.Species(sk.O3OSIRISRes(), sk.Labow())\n",
    "atmosphere['air'] = sk.Species(sk.Rayleigh(), sk.MSIS90())\n",
    "\n",
    "# Set the species to calculate the weighting function for\n",
    "atmosphere.wf_species = 'ozone'\n",
    "\n",
    "# And now make the engine\n",
    "engine = sk.EngineHR(geometry=geometry, atmosphere=atmosphere)\n",
    "\n",
    "# Choose some wavelengths to do the calculation at\n",
    "engine.wavelengths = [330]\n",
    "\n",
    "# Set up where we want to calculate the WF\n",
    "# Here we do 1000 m shells centered at 500m, 1500m, 2500m, ...\n",
    "wf_alts_m = np.arange(500, 55000, 1000)\n",
    "engine.options['wfheights'] = wf_alts_m\n",
    "engine.options['wfwidths'] = np.ones_like(wf_alts_m) * 1000\n",
    "\n",
    "# And do the calculation\n",
    "radiance, wf = engine.calculate_radiance()\n",
    "\n",
    "# wf is shape [wavelength, lines of sight, perturbation]\n",
    "plt.plot(wf[0, :, :].T, wf_alts_m)\n",
    "plt.xlabel('dI/dn')\n",
    "plt.ylabel('Altitude [m]')\n",
    "\n",
    "plt.show()"
   ]
  }
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