Given the way this question is phrased, I don’t think people will be able to answer it well unless they are already familiar with the specific data set you are working with. Here are some answers to more general questions, which may or may not be what you’re looking for but we can helpfully answer them:
-
What’s the difference between irradiance and radiation?
When reported on an hourly basis, there’s virtually no difference between these two. Irradiance is usually reported in Watts/m2 and is a unit of power while Radiation is reported in Watt-hours/m2 and is a unit of energy. But 1 Watt of power supplied over an hour is equal to 1 Watt-hour of energy. So you can use hourly solar irradiance data as input for the EPW radiation data. -
What’s the difference between solar irradiance and illuminance?
Solar irradiance is the total amount of power that comes from the sun on a given area. So it includes both the portion of the sun that is visible AND the portion of the sun that is infrared + ultraviolet, which cannot be seen by humans but can still be experienced as “heat”. Illuminance is also a measure of solar intensity but is only for the human-visible part of the spectrum. The units for irradiance (W/m2) and illuminance (lux) are completely different from one another and, while these two metrics have a (more-or-less) direct relationship, they CANNOT be used interchangeably. However, EPW illuminance is not used in E+ calculations so you can still make a E+ simulate-able EPW without illuminance data (radiation is required, though).
Hope that helps.