Campbell Scientific CNR2 Radiometer - Manual (Page 5)

CNR2 Net Radiometer
1. General Description
The CNR2 Net Radiometer is intended for the analysis of the radiation balance
of short-wave and long-wave infrared radiation. The most common application
is the measurement of total net radiation at the earth's surface.
The CNR2 design is such that both the upward facing and the downward-
facing instruments measure the energy that is received from the hemisphere.
The short-wave sensor, or pyranometer, has a field of view of 180 degrees on
the upper and 150 degrees on the lower detector. The long wave sensor, or
pyrgeometer, has a field of view of 150 degrees on the upper and the lower
detector. The output is expressed in Watts per square meter. The total spectral
range that is measured is roughly from 0.3 to 40 micrometers. This spectral
range covers both the solar radiation, 0.3 to 2.8 micrometers, and the far
infrared radiation, 4.5 to 42 micrometers.
The design of the CNR2 is such that short-wave radiation and long-wave
radiation are measured separately. Short-wave radiation is measured by two
pyranometers, one for measuring incoming short-wave radiation from the sky,
and the other, which faces downward, for measuring the reflected short-wave
radiation. The final result from these two pyranometers is net short-wave
radiation.
Long-waveradiation is measured by two pyrgeometers, one for measuring the
long-wave radiation from the sky, the other from the soil surface. Net long-
wave radiation is a final result of measurements from those two detectors.
Additional information on the CNR2 sensor can be found in the Kipp & Zonen
CNR2 Manual. The primary intent of this manual is to provide information on
interfacing the CNR2 to Campbell Scientific dataloggers.
2. Sensor Specifications
2.1 CNR2 Specifications
Response time: <10s
Temperature dependence of
sensitivity (-10 °C to +40°C): <5%
Sensor asymmetry: <5%
Sensitivities: 10 to 20 μV/W/m 2
Sensitivity change per year: <1%
Tilt error: <1%
Uncertainty in daily total: <10%
Cable length: Customer’s choice from 3 to 100 ft.
(Recommended are 50, 75, and 100 ft)
Weight: 250 g (add about 300g for each
30ft of cable)
1