Estimation of precipitable water vapour by GNSS meteorology in Black Sea region of Türkiye
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Emine Tanır Kayıkçı
, Kutubuddin Ansari
, Vincenza Tornatore
, Selma Zengin Kazancı und Mualla Yalçınkaya
Abstract
This study investigates the estimation of precipitable water vapour (PWV) using Global Navigation Satellite System (GNSS) meteorology in the Black Sea region of Türkiye, an area characterized by high rainfall and significant climatic variability. GNSS observations from four permanent stations (SAME, SOMU, MACK, and TRAB) between October 2017 and December 2019 were processed with Bernese 5.2 software to retrieve zenith total delay and derive PWV. The Vienna Mapping Function 1 (VMF1) was applied with a 10° elevation cut-off angle, and orography-dependent pressure and temperature fields were used for tropospheric modeling. The results were compared with radiosonde measurements from Samsun station and ERA-Interim reanalysis data to assess reliability. Findings show that GNSS-derived PWV varied between 1 and 46 mm, with strong seasonal and diurnal cycles higher in summer and daytime, and lower in winter and nighttime. Radiosonde PWV exhibited strong correlation with GNSS PWV (r > 0.9), while ERA-Interim tended to overestimate values, particularly at higher elevation sites. GNSS PWV demonstrated a strong positive correlation with surface temperature (∼0.8) and an inverse relationship with atmospheric pressure. These results confirm the potential of GNSS meteorology as a reliable tool for continuous and high-resolution monitoring of atmospheric water vapour, supporting weather forecasting and climate studies in the Black Sea region.
Funding source: The Scientific and Technological Research Council of Türkiye (TÜBİTAK) under the 1001 – Scientific and Technological Research Projects Funding Program.
Award Identifier / Grant number: 116Y186
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Research ethics: Not applicable.
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Informed consent: Not applicable.
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Author contributions: ETK and KA: writing and draft preparation; VT, SZK and MYK: contributed to improve the manuscript.
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Use of Large Language Models, AI and Machine Learning Tools: None declared.
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Conflict of interest: The author states no conflict of interest.
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Research funding: A major part of this study was conducted within the scope of the research project “116Y186 – Using Regional GNSS Networks to Strengthen Severe Weather Prediction”, supported by The Scientific and Technological Research Council of Türkiye (TÜBİTAK) under the 1001 – Scientific and Technological Research Projects Funding Program.
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Data availability: The GNSS data collected in the Black Sea region are available from TUSAGA-Aktif (https://www.tkgm.gov.tr/tr/icerik/tusaga-aktif-0), while the data from SAME, SOMU, TRAB and MACK GNSS stations were obtained within the scope of the project and archived on a high-capacity server located at the IT Department of Karadeniz Technical University (KTU), under an FTP address designated for the 116Y186 research project project (GNSS FTP Server). The ERA-Interim data set is obtained from ECMWF archives (http://apps.ecmwf.int/datasets/data/interim-full-daily/levtype=sfc/).
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