Dome Improvement for Pyranometers and Albedometers
Published: Wednesday, June 30, 2010
In the constant search to optimize performance Kipp & Zonen has improved the domes of its solar radiometers. The CMP 6, CMP 11 and CMP 21 pyranometers, and the CMA 6 and CMA 11 albedometers are now being produced with a new type of glass for both the inner and outer 2 mm domes.
The main benefit of the new glass is the wider spectral range at shorter wavelengths. The 50 % transmission point has been improved from 310 nm to 285 nm. The second improvement is that the new glass has 20 % better thermal conductivity. This results in a dome temperature closer to the temperature of the instrument body and therefore a lower offset due to thermal radiation.
The single 4 mm thick dome used on the CMP 3 pyranometer and the CNR 2 and CNR 4 net radiometers has also been improved and the 50% transmission point is now 300 nm instead of 310 nm.
These changes will not result in a mismatch with older instruments but gives a more accurate contribution from UV radiation. The long-wave 50% transmission point remains the same at 2800 nm.
The new domes will be fitted to pyranometers, albedometers and net radiometers shipping from July 2010.
Calculated relative transmittance of two domes including the wavelength dependent reflection losses