Monitoring groundwater changes in Turkey by GRACE and GRACE/-FO satellite missions

GRACE/-FO satellite missions have been monitoring the Earth's gravitational field and providing high-accuracy information about changes in water resources, changes in sea level, mass changes in glaciers, and changes in the gravitational field caused by earthquakes for the last 25 years. The aim of our thesis is to 1) Analyze change analysis of TWS and GWS data in the grids corresponding to 12 basins in Turkey, officially determined by DSI; 2) Investigate the applicability of G3P and GLDAS based GWS data on Türkiye. For these purposes, in 14 grids representing 12 basins; 1) GFZ, JPL and CSR TWS of GRACE/-FO missions, avg_TWS data obtained by calculating their average and COST-G TWS data, 2) G3P and GLDAS GWS data were used. In the analysis, evaluation and examination of TWS and GWS changes, 1) Trend estimation, significance and equivalence tests in time series, 2) Correlation analysis and significance tests, 3) Descriptive statistics and change analysis methods in time series were used. The thesis examined this topic, which is also important for environmental sciences, with geodetic methods and evaluated the results.