Modelling of the solar radiation diurnal variation

Hello.

I am working on modelling the solar radiation throughout the day which changes due to atmosphere conditions and sun position. I haven't found any usefull source so far and i was wondering if anyone has built any similar model? Either in matlab or simulink

Thank you

[per isakson]

Searching File Exchange for solar radiation returns 43 results.

[Eleni.T]

Most of the files in the file exchange are about solar radiation changing annually. My problem is that I want the variations throughout the day.

[per isakson]

"variations throughout the day" maybe one provides hourly data, e.g. "Clear Sky Modeling Tool".

"atmosphere conditions" does that include clouds?