Campbell NR-Lite, Instruction Manual

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NR-LITE Net Radiometer
The NR-LITE is a high-output thermopile sensor which measures the algebraic sum of
incoming and outgoing all-wave radiation (i.e. both short-wave and long-wave
components).
Incoming radiation consists of direct (beam) and diffuse solar radiation plus
long-wave irradiance from the sky. Outgoing radiation consists of reflected solar radiation
plus the terrestrial long-wave component.
The NR-LITE is equipped with Teflon-coated sensor surfaces. This results in a robust
design
which gives very easy maintenance and good sensor stability. However, this design
is slightly less accurate than the more traditional radiometers which use plastic domes.
1. General Description
Bird repelling stick
∅
16 x 800 Support Arm
∅
80
Bubble level indicator
Adjustable mounting arm
FIGURE 1. General View and Dimensions of NR-LITE
The NR-LITE is used for measuring solar and far infrared radiation balance.
This balance is known as the net (total) radiation. Its upwards facing sensor
measures the solar energy and far infra-red energy that is received from the
entire hemisphere (180° field of view). Its downwards facing sensor measures
the energy received from the surface of the soil. The two readings are
automatically subtracted and the result converted to a single output signal. This
output represents the net radiation, (which can be interpreted as meaning the
radiative energy that is seen at the surface) and is expressed in Watts per square
meter (W m
-2
).
The NR-LITE is designed for continuous outside use. The sensor surfaces are
coated with Teflon. This ensures good sensor stability, very long life and easy
maintenance compared to the more usual radiometers fitted with plastic domes.
However, it does have some disadvantages, particularly a higher sensitivity to
wind speed with a subsequent lessening of accuracy. It is, though, possible to
correct for the wind speed sensitivity if the sensor is installed in a system
where wind speed is also being measured.
Although net radiometers are usually used in meteorology to measure radiation
balance, the NR-LITE can also be used to measure indoor climate radiative
stress.