Great video. But one question. Re: Global, Direct and Diffuse irradiance (at ~ 10:35 onwards). Why is Global irradiance less that Direct irradiance? Isn't Global irr the sum of Direct, Diffuse & Atmospheric irradiance? And likewise, from 13:30 +, why does Global irr coincide with Diffuse irr? Shouldn't it include Atmospheric irradiance?