====== Setup for SCORE-MIP radiative transfer model intercomparison ======

{{:intercomparisons:scoremip:task1a_rt_comparison_march2010.pdf|Download pdf}}

[[:intercomparisons:scoremip:results|See results]]

==== Geophysical scenarios ====

  * for 5 different aerosol scenarios:
    - Low aerosol loading (AOD ~ 0.05); no cirrus cloud: use gas +  Rayleigh + aerosol (low_aod)
    - Low aerosol loading (AOD ~ 0.05) with cirrus cloud: use gas + Rayleigh + aerosol (low_aod) + cirrus
    - High aerosol loading (AOD ~ 0.3) no cirrus cloud: use gas + Rayleigh + aerosol (high_aod) 
    - High aerosol loading (AOD ~ 0.3) with cirrus cloud: use gas + Rayleigh + aerosol (high_aod) + cirrus
    - No aerosol (pure Rayleigh): use gas + Rayleigh
  * Geometry
    - Solar zenith angle: SZA = 10, **45**, 70
    - Viewing angle: nadir and sunglint
  * Surface
    - Lambert albedo (same in each band): 0.05, **0.1**, 0.3
    - Ocean sunglint: windspeed 5 m/s with viewing zenith angle = solar zenith angle

==== Setup of input layer data ====
  * For each layer of a 60 layer atmosphere:
    - Optical depth of gaseous absorption, aerosol, cirrus and Rayleigh extinction
    - Single scattering albedo of aerosols and cirrus
    - Scattering matrix for aerosols, cirrus and Rayleigh (layer independent)
  * Spectral range:
    - Band 1: O2 A-band:
      - **Window w1: 13080 – 13090 cm-1** (1000 spectral points)
      - Window w2: 12976 – 12980 cm-1 (400 spectral points)
    - Band 2: 1.61 micron CO2:
      - Window w1: 6202 – 6206 cm-1 (400 spectral points)
    - Band 3: 2.04 micron CO2:
      - Window w1: 4841-4845 cm-1 (400 spectral points)
      - **Window w2: 4815–4819 cm-1** (400 spectral points)

==== RT setup ====
  * The RT calculations for each scenario will be carried out for 4 setups of the RT code:
    - 'scalar accurate': scalar RT with standardized setups
    - 'scalar fast': fast version of scalar RT code
    - 'vector accurate': vector RT with standardized setups
    - 'vector fast': fast version of vector RT code
  * Parameters for ‘accurate’ setup: 32 full streams, delta-M on, single scattering correction on, plane parallel, 60 vertical layers 
  * ‘Fast’ setup: here the code should be run in a configuration so that the RT calculations are sufficiently fast for the retrieval of a large number of spectra
  *  Groups can also provide the RT calculations only for some of the 4 setups.

==== Reduced set of test cases ====

All combinations of parameters result in a very large set of spectra to be compared. As a first step we evaluate only SZA=45°, albedo=0.1 or BPDF, band 1 (window 1) and band 3 (window 2). 
 
This results in the following 20 test cases:

|                      | b1 w1 Lambert| b1 w1 Ocean | b3 w2 Lambert | b3 w2 Ocean|
|low aerosol           |  1a  |  1b  |  1c  |  1d  |
|low aerosol + cirrus  |  2a  |  2b  |  2c  |  2d  |
|high aerosol          |  3a  |  3b  |  3c  |  3d  |
|high aerosol + cirrus |  4a  |  4b  |  4c  |  4d  |
|pure Rayleigh         |  5a  |  5b  |  5c  |  5d  |
 


==== Input data ====

Please download the input data: {{:intercomparisons:scoremip:data.zip}}. 
   * The data directory contains subdirectories for aerosol, cirrus, gas and Rayleigh that contain files with the optical depth, single scattering abedo and scatteringmatrix
  * Optical depth for is given for each spectral point and each vertical layer. The uppermost layer and the last column is the optical depth of the bottom layer.
  * Single scattering albedo (ssa) for aerosol and cirrus is given for each spectral point
  * The input files are given for each spectral band separately. They will be identified with b1, b2, b3 for the O2 A Band, the 1.6 micron Band and the 2.03 micron band followed by the window number (w1 or w2). 
  * We assume that the scattering matrix is constant across each band, ie. only one scattering matrix is given per band. The scatteringmatrix file contains all 3 bands
  * Scattering matrix is given as alpha1-4,beta1-2 according to following representation (Note that alpha1 is the scalar phase function):
  * Rayleigh depolarization factor 0.0279	   
  * Please note that the forward peak of cirrus phase function has been truncated and the other optical properties of cirrus (single scattering albedo) have been modified accordingly.

==== Organization of output data ====

  * Give output as 2 column ASCII files with wavenumber and I or I-Q
  * Generate separate file for each geophysical scenario
  * Include header that provides information about the run (RT setup, code version etc). 
  * Start header lines with #
  * Provide the computation time for each scenario together with the computation time for the test programme (tespol.f90)