Campbell Scientific CNR1 Net Radiometer - Manual (Page 30)

Appendix A. CNR1 Performance and Measurements under Different Conditions
A-2
TABLE A-1. Typical output signals of CNR1 under different meteorological conditions.
Explanation can be found in the text.
Day
night
Cloudy
clear
+20 ºC
- 20 ºC CG3
Up
CG3
low
CM3
up
CM3
low
Pt 100 sky T
ground
T
d cloud 20 0 0 0-500 0-150 20 20 20
d cloud -20 0 0 0-500 0-150 -20 -20 -20
d clear 20 -100* 0 0-1300 0-400 20 1* 20
d clear -20 -100* 0 0-1300 0-400 -20 -53* -20
n cloud 20 0 0 0 0 20 20 20
n cloud -20 0 0 0 0 -20 -20 -20
n clear 20 -100*** 0 0** 0 20 1*** 20
n clear -20 -100*** 0 0** 0 -20 -53*** -20
* Values may suffer from the so-called window heating offset; the sun heats
the pyrgeometer window causing a measurement error of + 25 Watts per square
meter (maximum).
** Values may suffer from negative Infrared offsets, caused by cooling off of
the CM3 dome by Far Infrared radiation. The maximum expected offset value
is 15 Watts per square meter.
*** Values may suffer from dew deposition. This causes the CG3-up values to
rise from -100 to 0 Watts per square meter.