{
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  {
   "cell_type": "markdown",
   "id": "e451ae3f",
   "metadata": {},
   "source": [
    "# Multiple Species Weighting Function Calculations\n",
    "\n",
    "One of the most useful features of SK-DO is that it can compute weighting functions with respect to any number of input atmospheric species as well as surface reflectance."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "8b61b190",
   "metadata": {},
   "outputs": [],
   "source": [
    "%matplotlib inline"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "e58580cd",
   "metadata": {},
   "outputs": [],
   "source": [
    "import sasktran as sk\n",
    "import sasktran.disco.interface as do\n",
    "import numpy as np\n",
    "import matplotlib.pyplot as plt"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "c68e4f4b",
   "metadata": {},
   "source": [
    "Start by setting up the geometry, use a SZA of 60 degrees with a pure nadir viewing geometry.  Set up the atmosphere to contain rayleigh scattering, ozone and NO2 absorption, and a Lambertian surface"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "3a6db2b0",
   "metadata": {},
   "outputs": [],
   "source": [
    "geometry = sk.NadirGeometry()\n",
    "geometry.from_zeniths_and_azimuth_difference(60, 0, 0)\n",
    "\n",
    "atmosphere = sk.Atmosphere()\n",
    "\n",
    "# add our species\n",
    "atmosphere['rayleigh'] = sk.Species(sk.Rayleigh(), sk.MSIS90())\n",
    "atmosphere['o3'] = sk.Species(sk.O3OSIRISRes(), sk.Labow())\n",
    "atmosphere['no2'] = sk.Species(sk.NO2OSIRISRes(), sk.Pratmo())\n",
    "atmosphere.atmospheric_state = sk.MSIS90()\n",
    "\n",
    "# add our surface properties\n",
    "# setting to a scalar automatically sets the surface to be Lambertian\n",
    "atmosphere.brdf = 0.3"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e7f9fad3",
   "metadata": {},
   "source": [
    "Next we set the weighting function calculation to calculate with respect to all three species in the atmosphere as well as the surface"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "d2df49f1",
   "metadata": {},
   "outputs": [],
   "source": [
    "atmosphere.wf_species = ['rayleigh', 'o3', 'no2', 'brdf']"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "2d72093c",
   "metadata": {},
   "source": [
    "Run the calculation and print the results"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "09fe4932",
   "metadata": {},
   "outputs": [],
   "source": [
    "wavelengths = np.linspace(340,700, 361)\n",
    "engine = do.EngineDO(geometry=geometry, atmosphere=atmosphere, wavelengths=wavelengths)\n",
    "rad = engine.calculate_radiance()\n",
    "print(rad)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "7963dd78",
   "metadata": {},
   "source": [
    "In the resulting dataset we have weighting functions for the three species as a function of altitude, and the weighting function for the surface that is not a function of altitude."
   ]
  }
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