Dear college,

The solar flux (W / m2) is given by the meteorological services of each country.

Greetings in advance.

Dear Adel 

Thank you so much for your response, I know that, but I am foreign here so it is difficult to get the data.

Best Regards

have you checked PVGIS website

or weatherbase

they are based on NASA data

Dear Akram  

Thank you so much. I will try. 

 what is the location of your region you need the solar radiation