Definition of DHI, DNI, GHI

Forums: 

I am looking at the irradiance data for Cuidad Obregon (27.49, -109.94). I know that GHI includes both DNI and DHI. However, the data is showing a much larger value for DNI than for GHI at this location. (For example, for one data point, DHI is 19, DNI is 282, and GHI is 35) Can someone please explain to me how this is possible? Any help would be much appreciated!

You are right that GHI includes DNI... but it is something like GHI=DHI+DNIcos(i) (or a more refined formula) with i being the incident angle.