Construction of 3d models of the distribution of zenithal tropospheric delay components for the territory of Ukraine

The purpose of this work is to build 3D models of components of zenith tropospheric delay (ZTD) according to the surface measurements of meteorological values obtained at 100 points, which is almost evenly distributed throughout Ukraine. Method. Saastamoinen formulas calculated dry and wet components of the zenith tropospheric delay. According to the obtained results, the fields of dry and wet components of tropospheric delay were compiled, the fields of their change were constructed using a different number of studied points. Also, with the help of a graphic editor, 3D models of the magnitude one-moment distribution of dry and wet components of the zenith tropospheric delay for the territory of Ukraine were built. Results. Built 3D models of ZTD components; constructed zenith tropospheric delay fields for the territory of Ukraine; a comparison of the distribution of delay components for the specified area and its change during the day are the results of this work. It is established that the dry component becomes more important in the southern and central territory of Ukraine, where the observation points are lower in height and where there is a higher atmospheric pressure, which dominates in the calculation of this component. Accordingly, the wet component is also higher in the southern part of Ukraine, but this is due to higher relative humidity. As a result of the compaction of the network to 100 points, more accurate models of component distribution were obtained, which allowed Ukraine to assess in more detail the value of tropospheric delay for the territory of Ukraine. Further compaction of the network for the territory of Ukraine did not lead to the expected increase in the accuracy of tropospheric delay, as the location of meteorological stations in the country is not uniform enough, and some values of meteorological magnitudes are obtained not by direct measurements but by interpolation. It is necessary to compact the model with reliable meteorological measurements evenly and to control the calculation of components by integrating according to the aerological soundings carried out at individual points to obtain a more detailed model. Scientific novelty and practical significance. The scientific novelty is to build 3D models of tropospheric delay components for the territory of Ukraine at a certain point in time. The practical significance of the performed research is that they can be used as an initial step to build a Spatio-temporal model of tropospheric delay, reflecting the spatial changes of the delay in real-time for a particular area.