Estimation of integrated water vapour from GPS observations using local models in Hungary

Abstract

This paper studies the estimation of integrated water vapour (IWV) from the zenith tropospheric delay (ZTD). In order to evaluate the technique, six mathematical models are compared using a stormy summer period and a calm and dry winter period. The mathematical models include locally derived models using more than 10,000 radiosonde observations. The GPS derived IWV values are compared to radiosonde observations and a linear regression prediction of IWV using surface observations, too. Moreover the computations were carried out during a heavy storm in the summer period, when the estimated IWV distribution is compared to radar observations, too. The results show that the IWV values derived from GPS observations had an agreement with the radiosonde observations at the level of better than 2-3 mm in term of standard deviations. The results also show that GPS observations provide additional information to the estimation of IWV. Moreover the Hungarian Active GNSS Network was proved to be useful to monitor the water vapour content of the atmosphere during weather fronts as well. © Springer-Verlag Berlin Heidelberg 2012.