The total photon flux of UV radiation from sunlight is close to 8.5 % of the PPF in full sunlight. The photosynthetic photon flux at noon in full sunlight is about 2000 µmol m-2 s-1, thus the photon flux of UV radiation is about 170 µmol m-2 s-1.
WHY THIS SENSOR CANNOT SELECTIVELY MEASURE UV-B RADIATION (280-320 nm)
Our measurements confirm those of others and indicate that less than 0.4 % of the UV photon flux from sunlight falls below 320 nm 2.3 % falls between 320 and 350 nm, and 6 % falls between 350 and 400 nm.
Although the UV radiation between 250 and 320 nm is critically important in photochemical and photobiological reactions, only about 5 % of the UV photons are in this range. Because only a small fraction of the photons are in the UV-B range, this meter cannot be used to selectively measure UV-B radiation.
The sensor is sensitive to UV-B and UV-C radiation, but it is included with the UV-A radiation to provide a total measurement of UV radiation. The spectral response is shown on the graph.
Ordering Information:
SU-100 UV Sensor
uv-sensor-manual-2008