Campbell Scientific NR-LITE-L Kipp and Zonen Net Radiometer - Manual (Page 8)

NR-LITE Net Radiometer
FIGURE 4. Cosine Response of a Typical Net Radiometer
1.4 Sensitivity to Wind Speed
The calibration of the NR-LITE is carried out at zero wind speed. At any other
wind speed the sensitivity will decrease. It has been shown that this decrease in
sensitivity is less than 1% of reading per meter per second wind speed, and the
effect is essentially independent of the radiation level.
Net radiation readings can be corrected for wind speed sensitivity using the
following equation, which was developed by Jerry Brotzge at the Oklahoma
Climate Survey:
Wind Sensitivity equation for the NR-LITE:
Rn,cor = Rn,obs U < 5 m/s
Rn,cor = Rn,obs ∗ (1.0+A ∗ (U-5.0)) U > 5 m/s
Where,
Rn,cor = Net radiation corrected for wind speed
Rn,obs = Net radiation not corrected for wind speed
U = Horizontal wind speed in m/s
A = empirical constant derived from data = 0.021286
The following scatter plots illustrate the wind sensitivity for both the NR-LITE
and CNR1 net radiometer models.
4