API field
Diffuse horizontal irradiance
Sky light on a horizontal surface, per interval
Unit W/m²
What it is
The part of the horizontal sunlight that arrives from the sky rather than straight from the sun, averaged over each interval, in watts per square metre. It cannot exceed the global horizontal irradiance.
Typical values and how to get it
The values come from the uploaded file. When the file has only global irradiance, the parser estimates the diffuse part with the model chosen at upload, Erbs if none is chosen or DIRINT, and says so in its report. At upload, values above the global value are capped at the global value.
References
- Erbs, Klein & Duffie 1982, Estimation of the diffuse radiation fraction for hourly, daily and monthly-average global radiation, Solar Energy 28(4) 293–302
API
weather.diff_hor