Campbell NR01, Инструкция по эксплуатации

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NR01 Four-Component Net Radiation Sensor
13
6.6.2 Calibration Factors
Each NR01 is provided with a Certificate of Calibration by the manufacturer.
This certificate shows the sensor serial number and sensitivity for each of the
four component sensors. The individual calibration factors are unique to the
individual sensor and must be applied in the datalogger program to convert the
voltages to energy fluxes in W m –2 .
The calibration factor is in units of µV/(W m -2 ), which needs to be converted to
units of (W m
-2
)/mV for the multiplier parameter in the datalogger program.
To convert the units, divide the calibration factor into 1000. For example, if
the calibration factor is 7.30 µV/(W m -2 ), the multiplier is 1000/7.3 =
136.99 (W m -2 )/mV.
6.7 Instrument-Inversion Test
Campbell Scientific recommends performing the instrument-inversion test after
installation. This test consists of inverting the instrument position (180 degrees
turn) and looking at the output signals. The instrument output should have the
same magnitude but a reversed sign (so + to – and – to +). For best results,
perform this test on a clear day—preferably around noon (with the sun high in
the sky).
Deviations within ±10% can be tolerated. For optimal testing of pyrgeometers,
the test should be repeated on a clear night.
7. Operation
7.1 Measurement Principle
The NR01 typically measures net-radiation. The four components of net
radiation are measured and the net radiation is calculated:
The temperature (T
pyrgeo
) for the following formula is in Kelvin.
If the temperature is measured in degrees Celsius, add 273.15 to
the T
pyrgeo
value.
SW
in
= U
pyrano, up
/ E
pyrano, up
7-1
SW
out
= U
pyrano, down
/ E
pyrano, down
7-2
LW
in
= (U
pyrgeo, up
/ E
pyrgeo, up
) + 5.67.10 -8 (T
pyrgeo
) 4 7-3
LW
out
= (U
pyrgeo, down
/ E
pyrgeo, down
) + 5.67.10 -8 (T
pyrgeo
) 4 7-4
The instrument temperature is cancelled in the LW
net
:
LW
net
= U
pyrgeo, up
/ E
pyrgeo, up
- U
pyrgeo, down
/ E
pyrgeo, down
7-5
SW
net
= U
pyrano, up
/ E
pyrano, up
- U
pyrano, down
/ E
pyrano, down
7-6
NR = SW
net
+ LW
net
7-7
NOTE