GNSS meteorology and tomography applications to strengthen severe weather prediction in the black sea region

In this study, water vapor distributions were obtained by establishing GNSS test network in the vicinity of Samsun radiosonde (RS) station and in the Eastern Black Sea Region, which was most affected by heavy rainfall and flooding. Predictable water vapor (PWV), Zenit Total Delay (ZTD) and Slant Total Delay (STD) were calculated and compared with RS and numerical weather prediction (NWP). SAME-GNSS-derived PWV estimates are validated against 17030 Samsun radiosonde station observations with the accuracy of ±2 mm. NWP and experimental model PWVs compared to GNSS range from ±1.5mm to ±3.7mm. GNSS-PWV accuracy was obtained ±3.5mm with the interpolation of meteorological data, ±4.5mm with the GPT3 emprical model, and ±20mm with the ERA5 NWP data compared to RS-PWV. According to Samsun RS-ZTD, SAME GNSS-ZTD ±4.71mm and SAME-GOP-TropDBZTD ±7.56mm accuracy were obtained. Vienna mapping function and 5 degree elevation angle were used to compare STD data. STD results were compared to RS-STD as the referenced data. SAME-STD ±4.73mm, SAME-CHHR-STD with gradient mapping function coefficient (mfg) added ±4.07mm and SAME-GOP-TropDB STD ±8.87mm accuracy were obtained. Keywords: GNSS Meteorology, Zenit total delay, Zenit Wet Delay, Slant Total Delay, Slant Wet Delay, Predictable Water Vapour, Numerical Weather Model, Empirical Model