Estimation of vertical land motion along the south and west coast of Turkey from multi-sensor observations

Abstract

This study aims to estimate Vertical Land Motion (VLM) using multi-sensor and in-situ data at the tide gauge stations (TG) located on the western and southern coasts of Turkey. The analysis of tide gauge data, used to determine sea level changes for centuries, was supported by modern global geodetic observations, and the effect of VLM on the sea level trend was determined. In this context, VLM was calculated from the relative sea level trends of eight TG's between 1998 and 2018 and the absolute sea level trends obtained from the CTOH Along-Track Sea Level Anomalies regional products (X-TRACK) and Copernicus Marine Environment Monitoring Service (CMEMS) improved altimetry data covering the same temporal period. GNSS (Global Navigation Satellite System) measurements give a solution of the point-wise information about VLM at TG's, whereas InSAR (Interferometric Synthetic Aperture Radar) solutions give spatial information about VLM that were calculated from Sentinel-1 data, which was put into service after 2014. The analyses carried out on Turkey's south and west coasts revealed an uplift trend at all TG's, whereas an insignificant subsidence trend was determined at the MNTS tide gauge station. When focusing on the MNTS station, in the period of 1998–2018 VLM from XTRACK minus TG and CMEMS minus TG were estimated as −0.7 ± 0.9 mm/yr and −0.5 ± 0.8 mm/yr, respectively and also during the period of 2014–2018 VLM from GNSS and InSAR were estimated as −0.6 ± 0.2 mm/yr and −0.3 ± 0.1 mm/yr, respectively.