Hi all,

We are working on quantifying uncertainty in diffuse irradiance calculated
by the Perez model.
We quantify uncertainty by comparing Perez model outcomes against measured
diffuse irradiance on tilted surfaces through a mathematical formulation
that can identify where the Perez model falls short for its predictability.

For this analysis, we need the two measured data from the same period on the
same location:
(1) measured diffuse irradiance on tilted surfaces
(2) measured diffuse irradiance on horizontal surfaces (used as input for
the Perez model)

We have hard time obtaining enough data for analysis.

Can anyone know where we can access reliable dataset including the two
measured data?

Thanks,
Yeonsook