International Polarized Radiative Transfer intercomparisons

intercomparisons:a1_rayleigh

2015-03-10T16:39:41+00:00

Case A 1: Rayleigh scattering The most simple setup contains only one layer with scattering (non-absorbing) molecules. The radiance should be calculated for various geometries to check whether polarization is included correctly, in particular for special directions (e.g. solar zenith angle 0° or viewing zenith angle 0°). This test also checks, whether the Rayleigh depolarization factor is correctly included.

intercomparisons:a2_lambert

2015-03-10T16:41:35+00:00

Case A2: Rayleigh atmosphere with Lambertian surface Setup: * similar to case A1, with small modifications * surface albedo: 0.3 * optical thickness: 0.1 * Rayleigh depolarization factor: 0.03 * transmittance at bottom and reflectance at top of layer

intercomparisons:a3_aerosol_spherical

2015-03-10T16:42:36+00:00

Case A 3: Aerosol - spherical particles Setup: * typical water soluble aerosol for 50% relative humidity at 500 nm from OPAC database * aerosol optical thickness: 0.2 * aerosol optical properties: [netCDF], [ascii] The variable “phase” includes the phase matrix, as a function of the scattering angle (variable

intercomparisons:a4_aerosol_spheroid

2015-03-10T16:42:57+00:00

Case A 4: Aerosol - spheroidal particles Setup: * same settings as case A3 but for spheroidal aerosol particles * aerosol optical thickness: 0.2 * aerosol optical properties: [netCDF],[ascii] The variable “phase” includes the phase matrix, as a function of the scattering angle (variable

intercomparisons:a5_water_cloud

2015-05-19T12:42:21+00:00

Case A 5: Liquid water cloud The purpose of this test is to check whether the forward scattering peak and features of the phase matrix like the rainbow can be simulated. For this reason simulations in the principal plane and almucanter plane respectively are performed with an angular resolution of 1°.

intercomparisons:a6_ocean1

2025-09-11T12:13:09+00:00

Case A6: Ocean surface Setup: * Ocean reflectance matrix by Mishchenko's code ocean.shadow.f (uses anti-clockwise convention for azimuth angle!) * refractive index of water (1.33 + 0i) * wind speed 2m/s * scattering optical thickness (Rayleigh) of layer: 0.1

intercomparisons:b1_rayleigh

2015-03-10T17:04:58+00:00

Case B 1: Rayleigh scattering, standard atmosphere In this case it shall be tested whether the coupling between model layers is correctly included. Setup: * model atmosphere with 30 layers, optical thicknesses provided in . The file includes 2 columns where the first is the altitude of the layer boundaries in km, and the second is the layer optical thickness (e.g. the value for 0 km corresponds to the optical thickness for the layer from 0 to 1 km).

intercomparisons:b2_absorption

2015-03-10T17:07:22+00:00

Case B2: Rayleigh scattering and molecular absorption This test checks whether molecular absorption is correct. The setup is the same as for case B1 but with molecular absorption and at a different wavelength. Setup: * model atmosphere with 30 layers, scattering optical thicknesses provided in

intercomparisons:b2_absortpion

2014-10-30T10:14:31+00:00

Case B2: Rayleigh scattering and molecular absorption This test checks whether molecular absorption is correct. The setup is the same as for case B1 but with molecular absorption. Setup: * model atmosphere with 30 layers, scattering optical thicknesses provided in

intercomparisons:b3_aerosol

2015-03-10T17:08:21+00:00

Case B3: Aerosol profile This test case includes a standard atmosphere with Rayleigh scattering and molecular absorption (as case B2). Aerosol with a specified optical thickness profile is added. The aerosol optical properties are the same as in case A4 (spheroidal particles)

intercomparisons:b4_cloud_ocean

2015-03-10T17:08:39+00:00

Case B4: Standard atmosphere with cloud layer and underlying ocean surface This test case includes a standard atmosphere with Rayleigh scattering (as case B1). A cloud layer and an ocean surface is added. Setup: * model atmosphere with 30 layers, scattering optical thicknesses provided in

intercomparisons:c1_stepcloud

2018-01-08T12:22:58+00:00

Case C 1: Step cloud This test case has been adopted from phase 1 of the I3RC project (see ) Setup: [Definition of step cloud] * simple 1D step cloud * 32 pixels along the x-direction, first 16 have optical depth of 2, remaining have optical thickness of 18. * size of field is set to 0.5 km, i.e. all pixels have a width of 0.5/32 km

intercomparisons:c2_cubiccloud

2018-01-08T12:22:44+00:00

Case C 2: Cubic cloud Setup: [Definition of cubic cloud] * simple cubic cloud * domain: 7×7 km in x-y-plane, 5 km in z direction * cubic cloud 1x1x1 km in domain center: x: 3-4km, y: 3-4km, z: 2-3km * 70×70 pixels along x-y direction * periodic boundary conditions

intercomparisons:c3_cumulus

2018-01-08T12:23:36+00:00

Case C3: Cumulus cloud Setup: [Definition of cumulus cloudfield] * Cumulus cloud field from LES model (same as used in I3RC project, depending on LWC): , the format of the ascii file is as follows: Nx Ny Nz flag dx dy z1 z2 z3 .... ix iy iz ext Reff ...

intercomparisons:d1_rayleigh

2025-11-26T14:16:16+00:00

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 A1, only change from plane-parallel to spherical geometry.

intercomparisons:d2_lambert

2025-07-21T22:17:03+00:00

Case D2: Rayleigh scattering layer above Lambertian surface This case includes the same setup as case D1 but with smaller optical thickness and a Lambertian surface below the Rayleigh scattering layer. Setup: * optical thickness of layer: 0.1 *

intercomparisons:d3_aerosol_spherical

2025-09-15T12:37:15+00:00

Case D3: Aerosol layer (spherical) This case includes the same setup as case D1 but including spherical aerosol particles instead of molecules, the same as in case A3. Setup: * no molecules * typical water soluble aerosol for 50% relative humidity at 500 nm from OPAC database

intercomparisons:d4_aerosol_spheroid

2026-02-18T13:50:43+00:00

Case D4: Aerosol layer (spheroid) This case includes the same setup as case D1 but including spheroidal aerosol particles instead of molecules. Setup: * no molecules * aerosol optical thickness: 0.2 * aerosol optical properties: [netCDF],[ascii] The variable

intercomparisons:d5_water_cloud

2025-07-21T22:17:27+00:00

Case D5: Liquid water cloud layer This case includes the same setup as case D1 but including liquid cloud droplets. Setup: * cloud optical thickness: 5 * effective radius: 10 m * cloud optical properties: [netCDF],[ascii] The variable “phase” includes the phase matrix, as a function of the scattering angle (variable

intercomparisons:d6_mixed

2025-07-21T21:47:03+00:00

Case DX: Mixed particle types This case includes the same setup as case D1 but including a mixture of molecules, spherical and spheroidal aerosol particles. The aerosol optical properties are the same as defined in cases D3 and D4. Setup: * Molecular optical thickness: 0.5

intercomparisons:d6_ocean

2025-09-15T08:29:04+00:00

Case D6: Ocean surface This case includes the same setup as case D1 but including an ocean surface (reflectance matrix). Setup: * Ocean reflectance matrix by Mishchenko's code ocean.shadow.f (uses anti-clockwise convention for azimuth angle!) * refractive index of water (1.33 + 0i)

intercomparisons:e1_rayleigh

2025-07-21T22:17:43+00:00

Case E1: Rayleigh scattering, US standard atmosphere In this case we include the US standard atmosphere, the corresponding Rayleigh scattering optical thickness profile is provided for 450nm. Setup: * model atmosphere US-standard, scattering optical thickness provided in file

intercomparisons:e2_absorption

2025-07-21T22:17:49+00:00

Case E2: Rayleigh scattering and absorption, US standard atmosphere In this case we include the US standard atmosphere, the corresponding Rayleigh scattering optical thickness and molecular absorption profiles are provided at 320nm. Setup: * model atmosphere US-standard, scattering optical thickness provided in file

intercomparisons:e3_aerosol

2025-07-21T22:17:55+00:00

Case E3: US standard atmosphere and tropospheric aerosol layer In this case we include the US standard atmosphere, the corresponding Rayleigh scattering optical thickness and molecular absorption profiles are provided at 450 nm. In addition an aerosol layer is added between 0 and 3km altitude.

intercomparisons:e4_aerosol_stratos

2025-07-21T22:18:02+00:00

Case E4: US standard atmosphere and two aerosol layers In this case we include the US standard atmosphere, the corresponding Rayleigh scattering optical thickness and molecular absorption profiles are provided at 450 nm. In addition two aerosol layers are added: desert dust in the troposphere and sulfate in the stratosphere.

intercomparisons:e5_cirrus

2025-09-10T18:03:59+00:00

Case E5: US standard atmosphere and cirrus cloud In this case we include the US standard atmosphere, the corresponding Rayleigh scattering optical thickness and molecular absorption profiles are provided at 450 nm. In addition we include a cirrus cloud layer.

intercomparisons:e6_ocean_planet

2026-03-20T17:02:07+00:00

Case E6: Planet with US standard atmosphere and ocean surface In this case we include the US standard atmosphere, the corresponding Rayleigh scattering optical thickness and molecular absorption profiles are provided at 450 nm. Below we add a water surface described by a bidirectional reflectance distribution function including the specular reflection.

intercomparisons:intercomparison_studies

2014-10-30T10:14:31+00:00

Line-by-line calculations (GOSAT spectra) This intercomparison is part of the SWIR Carbon Observation Retrieval Model Intercomparison Project (SCORE-MIP). The objectives of SCOREMIP are to intercompare radiative transfer codes and retrieval methods used for

intercomparisons:intercomparisons

2026-02-16T09:18:32+00:00

IPRT polarized radiative transfer model intercomparison General conventions: * For all cases normalized radiances are compared (i.e. Stokes vector components devided by the extraterrestrial irradiance). * The viewing azimuth angle is defined clockwise

intercomparisons:scoremip

2014-10-30T10:14:31+00:00

SWIR Carbon Observation Retrieval Model Intercomparison Project (SCORE-MIP) Hartmut Boesch, Andre Butz, Yukio Yoshida, and Claudia Emde Comparison of scalar and vector radiative transfer codes Objective: Radiative transfer intercomparisons of scalar and vector RT codes for synchronized layer properties for the SWIR spectral range.