Originally Posted by Patrick LEE
I forgot to say that the RANDU function is only for the cumulus cloud cover. You need to consider the large-scale clouds as well.
The above statment is wrong. In Model II, the random numbers are used to speed up the calculation for both large-scale clouds and moist convective clouds.
My memory about Model II has clearly faded away much earlier than I thought. Sorry for the above mistake and sorry for correcting it so late. I has just found out this mistake as I am working on the clouds again and checking many papers.