Instrument: Photosynthetically Available Radiation Sensor
A PAR sensor measures photosynthetically available (or active) radiation. The sensor measures photon flux density (photons per second per square meter) within the visible wavelength range (typically 400 to 700 nanometers). PAR gives an indication of the total energy available to plants for photosynthesis. This instrument name is used when specific type, make and model are not known.
Biospherical light meter (model PNF-2102P)
Profiling Natural Fluorescence Radiometer: Unlike strobe fluorometers, a natural fluorometer measures fluorescence emitted under the ambient light conditions that are driving photosynthesis in situ.