I don't know too much about what you are doing, but if you want a good answer I would start with the code. In the phys directory you can look at the individual radiation schemes and the radiation driver.
I don't know if you desire instantaneous values or accumulated (or average) values.
Most schemes have comments which point to the articles which more clearly (hopefully) state what assumptions are made and outline the general technique of the computations.
The views expressed in this message do not necessarily reflect those of NOAA or the National Weather Service or the University of Oklahoma.
James Correia, Jr