Hi everyone,
I am sorry for my careless, and the RegCM can use the albedo from the CLM, whereas it will use the BATS method to avoid the FPE problem, because when cosz<=0 CLM assigns albedo to be equal to 1.
However, could anyone please explain what is the FPE problem?  And I find if I do not use the BATS to calculate the albedo the model works well too.
Thank you very much!
Sincerely
Sun Chao