Kipp&Zonen CM 4 Pyranometer User Manual
Page 44
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APPENDIX I
PYRANOMETER CLASSIFICATION
ACCORDING TO WMO GUIDE 1996
Characteristics
High
quality
Good
quality
Moderate
quality
ISO 9060 classification
Secondary
standard
First class
Second class
Response time (95 percent response)
< 15 s
< 30 s
< 60 s
Zero offset:
(a) Response to 200 W/m
2
net thermal radiation
(ventilated)
(b) Response 5 K/h change
in ambient temperature
± 7 W/m
2
± 2 W/m
2
± 15 W/m
2
± 4 W/m
2
± 30 W/m
2
± 8 W/m
2
Resolution (smallest detectable
change)
± 1 W/m
2
± 5 W/m
2
± 10 W/m
2
Stability (change per year,
percentage of full scale)
± 0.8
± 1.5
± 3.0
Directional response of beam
radiation
(The range of errors caused by
assuming that the normal incidence
responsivity is valid for all directions
when measuring, from any direction,
a beam radiation whose normal
incidence irradiance is 1000 W/m
2
)
± 10 W/m
2
± 20 W/m
2
± 30 W/m
2
Temperature response (percentage
of maximum due to any change of
ambient temperature within an
interval of 50 K)
± 2
± 4
± 8
Non-linearity (percentage deviation
from the responsivity at 500 W/m
2
due to any change of irradiance
within the range 100 to 1000 W/m
2
)
± 0.5
± 1
± 3
Spectral sensitivity (percentage of
deviation of the product of spectral
absorptance and spectral
transmittance from the corresponding
mean within the range of 0.3 to 3
μm)
± 2
± 5
± 10
Tilt response (percentage deviation
from the responsivity at 0
° tilt,
horizontal, due to change in tilt from
0
° to 90° at 1000 W/m
2
irradiance)
± 0.5
± 2
± 5