Campbell Scientific SP-LITE Solar Radiation Sensor - Manual (Page 6)

SP-LITE Silicon Pyranometer
2
FIGURE 2. SP-LITE Electrical Circuit
1.2 Spectral Properties
The spectral properties of the SP-LITE are mainly determined by the spectral
response of the photodiode, which is shown in Figure 3, below.
FIGURE 3. Spectral Sensitivity of Pyranometers Compared with Solar
Radiation
The SP-LITE is calibrated for solar radiation under clear sky conditions. The
spectrum for these conditions, at sea level, is also shown in Figure 3.
Unfortunately, however, the actual solar spectrum varies as a function of cloud
cover, season and solar elevation. Since the pyranometer does not have a flat
sensitivity across the whole solar spectrum, the accuracy of its response will
vary. However, the error range across the whole spectrum has been proven to
be small. The maximum total estimated error will only be in the region of ±5
percent when compared to the calibration conditions.