Calculate the solar irradiance spectrum in the spectral range from 400nm – 800nm. Use rte_solver disort with and without delta-scaling (deltam on/off). Assume that the cloud scattering phase function can be approximated by a Heney-Greenstein phase function (see exercise 5), which is done in the libRadtran input file as follows:

wc_hg.inp

wc_properties hu    # parameterization for water clouds 
# wc_modify gg  set  0.86   # specify asymmetry parameter
# wc_modify tau set  10     # specify cloud optical thickness

The parameterization by Hu uses a Heney-Greenstein approximation for the phase function. Compare results with and without delta scaling. Calculate also the nadir radiance and check how much the radiance is influenced by delta-scaling.

How does the irradiance depend on the cloud optical thickness and on the asymmetry parameter?