==== 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:phase_b:tau_rayleigh_800.dat|}}, no molecular absorption 
  * wavelength: 800 nm 
  * Rayleigh depolarization factor: 0.03

  * Ocean reflectance matrix by Mishchenko's code [[http://www.giss.nasa.gov/staff/mmishchenko/ftpcode/ocean.shadow.f|ocean.shadow.f]] (uses anti-clockwise convention for azimuth angle!)
  * refractive index of water (1.33 + 0i)
  * wind speed 2m/s
 
  * cloud layer between 2 and 3 km, optical thickness of 5
  * effective radius: 10 <m>mu m</m>
  * cloud optical properties: {{:intercomparisons:phase_a:watercloud.mie.cdf|netCDF}},{{:intercomparisons:phase_a:watercloud.mie.dat|ascii}} \\ The variable "phase" includes the phase matrix, as a function of the scattering angle (variable "theta"). The 4x4 scattering phase matrix for spherical droplets has four non-zero elements, which are stored in the following order: $ P = \begin{pmatrix} P1 &  P2 &  0 & 0 \\ P2 & P1 & 0 & 0 \\ 0 & 0 & P3 & P4 \\ 0 & 0 & -P4 & P3 \end{pmatrix} $ \\ The corresponding Legendre polynomials ("pmom") and the single scattering albedo ("ssa") are also included in the file.
  
  * output altitudes: 0 km, 1 km, 30 km
  * sun position  (//sza//=60°, //saa//=0°)
  * viewing zenith angles: 
    * at 0 km : //vza//: 0° - 85°, 5° increment
    * at 1 km:  //vza//: 0° - 180°, 5° increment (without 90°)
    * at 30 km: //vza//: 95° - 180°, 5° increment 
  * viewing azimuth angle //vaa//: 0° - 180°, 5° increment	     

//Output format://
  * The output should be provided in the same format as for case A1 ([[intercomparisons:a1_rayleigh|Rayleigh scattering]]).

 
=== Results ===

//Difference plots// between the models IPOL, 3DMCPOL, SPARTA (previously named TROPOS), SHDOM, PSTAR and MYSTIC for the full radiation field:\\
{{:intercomparisons:phase_b:b4:diff_b4_3dmcpol.pdf|3DMCPOL}}\\
{{:intercomparisons:phase_b:b4:diff_b4_ipol.pdf|IPOL}}\\
{{:intercomparisons:phase_b:b4:diff_b4_tropos.pdf|SPARTA}}\\
{{:intercomparisons:phase_b:b4:diff_b4_shdom3.pdf|SHDOM}}\\
{{:intercomparisons:phase_b:b4:diff_b4_pstar.pdf|PSTAR}}\\

//Data// of all models (MYSTIC and 3DMCPOL include also standard deviation):\\
{{:intercomparisons:phase_b:b4:iprt_case_b4_mystic.dat|MYSTIC}}\\	 
{{:intercomparisons:phase_b:b4:iprt_case_b4_3dmcpol.dat|3DMCPOL}}\\
{{:intercomparisons:phase_b:b4:iprt_case_b4_ipol.dat|IPOL}}\\
{{:intercomparisons:phase_b:b4:iprt_case_b4_tropos.dat|SPARTA}}\\
{{:intercomparisons:phase_b:b4:iprt_case_b4_shdom3.dat|SHDOM}}\\
{{:intercomparisons:phase_b:b4:iprt_case_b4_pstar.dat|PSTAR}}\\