A Calibration System for Reference Radiosondes that Meets GRUAN Uncertainty Requirements
Hannu Sairanen, Martti Heinonen, Richard Högström, Antti Lakka, Heikki Kajastie
by NCSLI Measure (NCSLI) at 2014
A new International System (SI) traceable calibration set-up for reference radiosondes is presented here with a preliminary uncertainty analysis. By meeting the GRUAN requirements, this development fulfils the needs of the meteorological community for disseminating SI traceability to upper air humidity measurements with reduced uncertainty. The set-up was designed for calibrations from laboratory temperature down to 183 K and in terms of dew-point temperature from 193 K to 283 K. To enable rapid changes in humidity and to shorten the time needed for a single calibration, the set-up utilizes a hybrid humidity generator method in which two air flows with known water vapor concentrations are mixed. According to a preliminary uncertainty analysis, the relative expanded uncertainty (k = 2) of the set-up is less than 2 % expressed in terms of mixing ratio.
Hannu Sairanen, Martti Heinonen, Richard Högström, Antti Lakka & Heikki Kajastie (2014) A Calibration System for Reference Radiosondes that Meets GRUAN Uncertainty Requirements, NCSLI Measure, 9:3, 56-60, DOI: 10.1080/19315775.2014.11721696
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