The role of GNSS infrastructure in the monitoring of atmospheric water vapor

Szabolcs Rózsa, Tamás Weidinger, András Zénó Gyöngyösi, Ambrus Kenyeres

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5 Citations (Scopus)


The observations of the Global Navigation Satellite Systems (GNSS) are affected by various systematic error sources. These effects are usually eliminated in positioning applications using a suitable processing technique. With the emerging active GNSS networks, it became possible to use the GNSS infrastructure for monitoring various parameters of the atmosphere. One of these error sources is the delaying effect of the troposphere due to the atmospheric masses including the water vapor, too. The observed tropospheric delays can be used for monitoring the water vapor content of the troposphere. In several regions of the world GNSS derived products are already used on a routine basis for numerical weather prediction. With the establishment of the active, GNSS network in Hungary, it became feasible to quantify and monitor the precipitable water vapor (PW) in the atmosphere. The advantage of this solution is the high spatial (approx. 60 km) and temporal (hourly, sub-hourly) resolution of the observations. This paper introduces the near real-time processing system of GNSS observations in Hungary. The hourly observations of 35 Hungarian permanent GNSS reference stations are processed. This network is extended beyond the territory of Hungary with some 50 stations covering Eastern and Central Europe. The estimation of the PW from the zenith wet tropospheric delay (ZWD) is carried out in near-real time. Firstly, the zenith hydrostatic delays are subtracted from the estimated total delays. Afterwards, the wet delays are scaled to precipitable water vapor content. Among the well known global models, some local models are also introduced to compute the scaling factor between the zenith wet delay and the PW. The GPS derived PW values are validated by radiosonde observations over Central Europe, and they are also compared with some numerical weather model estimations, too. The results show, that the estimated PW values agree with the radiosonde observations with the accuracy of slightly more than 1 mm in terms of standard deviation and a bias of 1 mm.

Original languageEnglish
Pages (from-to)1-20
Number of pages20
Issue number1
Publication statusPublished - Jan 1 2012



  • Numerical weather prediction
  • Precipitable water
  • Radiosonde observations
  • Tropospheric water vapor

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Rózsa, S., Weidinger, T., Gyöngyösi, A. Z., & Kenyeres, A. (2012). The role of GNSS infrastructure in the monitoring of atmospheric water vapor. Idojaras, 116(1), 1-20.