We have recently published the following paper.
Sugidachi, T., and M. Fujiwara (2013), Correction of the stepwise change observed at 0C in Meisei RS2-91, RS-01G, and RS-06G radiosonde relative humidity profiles, Journal of the Meteorological Society of Japan, 91(3), 323-336, doi:10.2151/jmsj.2013-306.[link]
In this study, we re-evaluated the dependence on temperature and humidity of the MEISEI relative humidity (RH) sensors using a climate chamber for -50 deg.C to +40 deg.C. We also evaluated the influence of temperature lag of the RH sensors during tropospheric ascent (the sensors are always slightly warmer than the ambient air because of the air temperature decrease with height). We propose a new temperature-dependence RH correction scheme for the recent MEISEI radiosondes. This should be applied to the past MEISEI sounding data in Japan, Indonesia, and at some other sites where the MEISEI radiosondes were used. In the paper, we followed the guidelines by Joint Committee for Guides in Metrology/Working Group 1 (JCGM/WG1) (2008) (“Evaluation of measurement data – Guide to the expression of uncertainty in measurement”) to estimate the measurement uncertainties associated with the chamber experiments.