Campbell Scientific NR01 Net Radiometer - Manual (Page 6)

NR01 Four-Component Net Radiation Sensor
FIGURE 1-1. Atmospheric Radiation as a Function of Wavelength
LW or FIR radiation is mainly present in the 4500 to 50000 nm region, while SW or solar radiation is
mainly present in the 300 to 3000 nm region. The two are measured separately.
Major improvements of the NR01 relative to comparable instruments include
reduced weight, reduced solar offsets in the LW signal, ease of leveling
(because a 2-axis leveling assembly is built-in).
The NR01 serves to measure the four separate components of the surface
radiation balance. Working completely passive, using thermopile sensors, the
NR01 generates four small output voltages proportional to the incoming and
outgoing SW and LW fluxes; SW
in
or global solar radiation, SW
out
or reflected
solar radiation, LW
in
or infrared emitted by the sky and LW
out
or infrared
emitted by the ground surface.
From these also parameter like SW “albedo”, “sky temperature”, “(ground)
surface temperature” and off course “net-radiation” (net value of all SW and
LW fluxes) can be calculated.
The SW sensors are also called pyranometers (type SR01); the LW sensors are
called pyrgeometers (type IR01). For calculation of the sky and surface
temperature, a PT100 temperature sensor is included in the connection body of
the pyrgeometers. A heater is also included in the pyrgeometers’ connection
body to heat the pyrgeometers, which prevents the deposition of dew.
The NR01 requires leveling; a two-axis leveling facility is incorporated in the
design. See the chapter on installation.
Using the NR01 is easy. For readout one only needs four analog input
channels, and, only if sky and surface temperature are required, a way to
measure the PT100. If power is available, Campbell Scientific recommends
heating the pyrgeometers from sundown to sunset.
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