This help article will be broken into two sections. The first for Solar Radiation / Solar Irradiance parameters. The second for Simple PV Power parameters.
Solar Radiation
In the forecast data, the following parameters (attributes) are provided:

For the live data (estimated actuals), the following parameters are provided:

Simple PV Power
In the forecast data, the following parameters (attributes) are provided:

For the live data (estimated actuals), the following parameters are provided:

For further information, consult the Solcast API documentation