==== 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. 

//Setup://

  * model atmosphere US-standard, scattering optical thickness provided in file {{:intercomparisons:phase_e:tau_rayleigh_450nm_usstd.dat|}}, molecular absorption optical thicknes in {{:intercomparisons:phase_e:tau_absorption_450nm_usstd.dat|}}. 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).
  * The surface is described by the ocean reflectance matrix using Mishchenko's code [[http://www.giss.nasa.gov/staff/mmishchenko/ftpcode/ocean.shadow.f|ocean.shadow.f]] (uses anti-clockwise convention for azimuth angle!)
  * wind speed: 5 m/s
  * mean surface slope, according to Eq. 18 in Mishchenko and Travis 1997:\\ 2$\sigma^2$ = 0.5 $\cdot$ (0.003 + 0.00512 $\cdot$ u$_{10}$), where u$_{10}$ is the wind speed
  * refractive index of water: 1.33+0i
  * wavelength: 450 nm 
  * Rayleigh depolarization factor: 0.03
  * Earth radius: 6371 km
  
  * Observer at 3.0e5 km distance from center of Earth at (lan, lon)=(0°, 0°)
  * Field of view includes complete planet:
    * zenith angles: //vza:// -1.2° - +1.2°, increment 0.04°
    * azimuth angles: //vaa:// -1.2° - +1.2°, increment 0.04°
    * Here the angles refer to the connection line between Earth center and observer.  
  * Sun position:
    * latitude: //lat:// 0°
    * longitudes: //lon:// 50°, 90°, 110°, 130°
    * The longitude of the sun position corresponds to the phase angle.