“Non-geodetic” approaches in the analysis of terrestrial CDGPS data for the retrieval of the atmospheric precipitable water at local scale during severe weather phenomena

Precipitable water (PW) derived from the CDGPS (Continuous Differential Global Positioning System) zenith tropospheric delay (ZTD) is evaluated through comparison of three procedures: using GPT (Global Pressure and Temperature) and GPT2 global models as well as observed data. The results show that the difference between PW retrieved from models (GPT and GPT2) and PW obtained by observed meteorological data, at least for sites and period observed in this paper, is also a function of the position of the station. The short period considered does not allow for any consideration of possible intra-annual or annual periodicity. The analysis of the residuals between observed PW and modeled PW shows a peak before the rain event.