International Polarized Radiative Transfer

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.

General definition of angles for all simulations in spherical geometry: We refer to the angles at the position of the observer, i.e. at the top of the atmosphere VZA=θ_v' and SZA=θ₀'. For the observer at the surface VZA=θ_v and SZA=θ₀. The azimuth angles also refer to the position of the observer. The figure is taken from Gao et al. 2023.

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 IPRT_phase3_MODELNAME.nc.