Coastal motion at tide gauge stations along the Black Sea coast from in-situ and space-based observations

Abstract

The aim of this study is to determine the vertical land motion (VLM) and horizontal land motion (HLM) at the tide gauge stations located along the coast of the Black Sea using ground-based (GNSS and tide gauge) and satellite-based (satellite altimetry and InSAR) data. In this context, the tide gauge data were initially obtained from the Turkish Sea Level Monitoring System (TUDES) and Permanent Service for Mean Sea Level (PSMSL) data archive. The XTRACK data set, adopting the coastal altimetry approach, was selected as the satellite altimetry data, and sea level data from both methods were subjected to the Least Squares Parameter Estimation to determine sea level trends. The trends in sea level during the time period of 1993-2022 have been estimated based on the installation dates of tide gauge stations, using data from both tide gauge stations and satellite altimetry. In the analyses based on sea level data, subsidence trends were determined between the years 1993-2022 at the AMSR, TRAB, and POTI tide gauge stations, while an uplifting trend in VLM was observed at the other stations. These values were compared with the results obtained from GNSS observations at the tide gauge stations using the GAMIT/GLOBK software, yielding consistent outcomes. Furthermore, through the evaluation of GNSS data, the HLM at all tide gauge stations in the Black Sea region was estimated to be 1.4 +/- 1.7 mm/yr in the northeast direction (approximately 63 degrees).Additionally, a regional sea level trend map was generated using XTRACK satellite altimetry data from 1993 to 2022, revealing a sea level rise trend of 1.3 +/- 0.6 mm/yr in the Black Sea.