Measuring Dose, for instance PAR-dose, is a very practical way  to achieve data reduction and moreover getting more reliable results in general.

PAR-dose or energy is the Integrated Irradiance over elapsed Time and is normally expressed in w.sec.m-2

or microEinstein.m-2.

PAR-dose divided by the time span used is the averaged Irradiance.

One has the possibility of averaging short term effects as wave glitter or even long term variation by choosing the time span.

Integration generally will improve the overall accuracy of light detection when irradiance variation in a given time span is less important.

Integrated Irradiance is the Energy or Dose irradiated at the sensor position.

Averaged Irradiance is the Power irradiated.

Energy and Power irradiated are expressed as surface densities: m-2.

Light to frequency devices are very suitable for irradiance integration.