KZ CG4
ISFS uses CG4s to measure broadband infrared radiation. These often are used in upward and downward-looking pairs to obtain the net infrared radiation. These also are often combined with CM21s to obtain all four radiation components.
These sensors are similar to Eppley PIRs though lighter which makes them easier to deploy. Furthermore, results from EBEX suggest that the Kipp & Zonen sensors are more accurate than the Eppleys and the CG4 has a smaller dome temperature correction than the PIR. Thus, we plan to utilize these sensors more in future deployments. Our CG4s do not have a Tdome sensor, so it is not possible to implement a dome heating correction. The CG4 manual states that the dome-case temperature difference is no more than 0.3C and would produce an error of less than 4 W/m^2. The manual also says that the CG4 does not need to be shaded from direct sun (the shortwave radiation correction). Data shown by H. Naganuuma (http://www.gewex.org/BSRN/BSRNagendafinal.htm) show the CG4 reading lower by 5 W/m^2 when shaded from full sun (f=~0.5%).
We have deployed these with and without ventillated housings to keep the domes clean and now are using them with CVF4 ventillators.
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