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Incoming radiation variables

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michael3911

New member
Hello,

I am wondering if there is any difference between SWDNB and SWDOWN variables for shortwave incoming radiation and between GLW and LWDNB for longwave radiation? I have found a 0.001 W.m-2 difference in domain maximum for SW variables (using ncview) but otherwise both SW and LW variables seem to be identical or very similar. I would like to compare modelled fluxes with observations.

Thank you.
Michael
 
Michael,
SWDNB and SWDOWN have the same physical meaning and they should be identical. The same for GLW and LWDNB. However, note that SWDNB is directly output from radiation scheme, while SWDOWN is derived from GSW and albedo (SWDOWN(I,J)=GSW(I,J)/(1.-ALBEDO(I,J)))
I guess this might cause slight difference between the two variables.
I would suggest you use SWDNB to compare with in-situ observations. This is because, unless there is accurate measurement, we are not sure how precise albedo is. Bias in albedo may introduce bias to SWDOWN.
 
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