==== Case D1: Rayleigh scattering ====

The most simple setup contains only one layer with scattering (non-absorbing) molecules. Radiance shall be calculated for various sun-observer geometries, for twilight conditions and for limb observation geometries. We use the same model setup as for case B1, only change from plane-parallel to spherical geometry.  

//Setup://

  * optical thickness of layer: 0.5
  * Rayleigh depolarization factor: 0.03
  * no molecular absorption
  * Earth radius: 6371 km
  * Thickness of layer: 100 km

  * D1_1: Twilight radiance field (normalized to incident irradiance) at the bottom of the layer:
    * sun position: //sza//:92°, //saa//:65°
    * viewing zenith angles: //vza//: 0° - 90°, 5° increment (up-looking)
    * viewing azimuth angles: //vaa//: 0° - 360°, 5° increment	     

  *D1_2: Limb radiance at top of atmosphere for 20 km tangent height
    * viewing zenith angle at TOA: //vza//: 81.9°
    * viewing azimuth angle at TOA: //vaa//: 30°
    * solar zenith angles: //sza//: 0° - 90°, 5° increment 
    * solar azimuth angles: //saa//: 0° - 360°, 5° increment	     
  

//Output format://

Please include your data in the netcdf file {{:intercomparisons:phase_d:iprt_phase3_model.nc|IPRT_phase3_MODELNAME.nc}}.