The purpose of this paper is determining the water vapor content calculated by the wet component of zenith tropospheric delay (ZTD) obtained by means of radio sounding data and GNSS observations. The investigation methodology is the following: the wet component of ZTD is defined as the difference between the total ZTD derived from GNSS measurements and the calculated hydrostatic component. Then the integrated and precipitable water vapor (PWV) is calculated by means of the wet component. The radio sounding data from Kyiv aerological station as well as the zenith tropospheric delay data from the GLSV GNSS station were processed for six days of each month of 2016. The study results represent the wet component of ZTD and PWV values obtained by the radio sounding data and derived from GNSS observation data. Accuracy evaluation was carried out by the differences between wet component values obtained from the radio sounding data and defined from GNSS measurement data. An analogical accuracy evaluation was made for the PWV values as well. The scientific novelty and practical significance are that the obtained results will serve as the basis for further increasing of determination accuracy of the wet component from GNSS measurements, in particular, to determine its spatial and temporal changes and the PWV content in the atmosphere, which are important for weather forecasting in this region.
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