Campbell Scientific NR01 Net Radiometer User Manual
Page 13
NR01 Four-Component Net Radiation Sensor
TABLE 2.5-1. Average Global Radiation Values
at the Earth Surface
Type SW
in
SW
out
SW
net
LW
in
LW
out
LW
net
Net
Units W/m
2
W/m
2
W/m
2
W/m
2
W/m
2
W/m
2
W/m
2
Value 198
- 30
168
324* -390**
-66
102
* LW
in
value assumes a sky temperature of 2ºC.
** LW
out
value assumes a surface temperature of 14ºC.
The LW radiation values in Table 2.5-1 are corrected for sensor
temperature. The values in Table 2.5-2 are not corrected for
sensor temperature.
NOTE
On a smaller timescale, the most important factors are:
• solar position
• cloud cover
The ambient air temperature is less important because cloud base temperature
tends to follow surface temperature.
TABLE 2.5-2. Expected SENSOR Outputs when Measuring with the NR01
D / N
CD / CR
Ambient
air temp.
pyrgeo
down
#
pyrgeo
up
#
pyrano
down
pyrano
up
T
sky
T
ground
°C
W/m
2
W/m
2
W/m
2
W/m
2
°C
°C
D
CD
+20
0
0
0-500
0-150
20
+20
D
CD
-20
0
0
0-500
0-150
-20
-20
D
CR
+20
-70**
0
0-1500
0-400
+1
+20
D
CR
-20
-70**
0
0-1500
0-400
-50
-20
N
CD
+20
0
0
0
0
+20
+20
N
CD
-20
0
0
0
0
-20
-20
N
CR
+20
-70*
0
0***
0
1
+20
N
CR
-20
-70*
0
0***
0
50
-20
The table makes a distinction between the day and night (D/N), cloudy and
clear (CD / CR) conditions, and high and low ambient air temperatures.
The instrument temperature is normally close to air temperature.
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