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swint_opt = 2 is diagnostic variable?


New member
I am wondering if setting like swint_opt = 2 is only for SWDDNI2 as a diagnostic variable. Radiation scheme by RRTMG produces the SWDOWN as well as SWDDNI, which are employed into the land surface model and PBL scheme. I mean those variables interact with the other variables in physics parameterization.

Setting swint_opt=2 is only for producing the SWDDNI2 as a diagnostic variable by using the current hydrometeors and look up table to identify the solar ramp. Those do not interact with the other variables in physics parameterization.

I am not sure if my understanding is correct.

It would be good if you let me know it.

Thanks in advance.
Last edited:
swint_opt is a namelist option that tells the model how to process short-wave radiation based on the updated solar zenith angle between SW call

swint_opt = 0: no interpolation
swint_opt = 1: use interpolation
swint_opt = 2: calls FARMS every model time step

Hope this is helpful for you.
Thanks for your reply. My question is if solar radiation from FARMS every model time step interacts with the other parameterization such as PBL or soli model.
you need to set up couple_farms to true in the namelist for the GHI from FARMS to be used in the surface energy balance. Otherwise FARMS outputs are only diagnostic variables.