Makineci, M.N.Doğanalp, S.2025-02-102025-02-1020222687-4997https://doi.org/10.51489/tuzal.1152563https://hdl.handle.net/20.500.13091/9870The Caspian Sea is the world's largest inland water body, studied for years. The Caspian Sea, in which water level changes were examined with the data acquired from tide gauges in the past years, is also observing using altimeter satellite data with the improvement of satellite programs. In addition, water mass changes can be investigated with the GRACE and GRACE Follow-On (GRACE-FO) satellites, which can capture mass changes on the earth. Within the scope of the study, the Equivalent Water Thickness (EWT) changes in and around the Caspian Sea were examined using Level-2 Release-06 data obtained from the GRACE/GRACE-FO satellites with a long-term data set covering the years 2002-2021. While making the calculations, a long-term average model was created, and the average value of each year was subtracted from the average model. Center for Space Research (CSR) was preferred as the data center, and the Decorrelation Filtering (DDK) technique was used to eliminate correlation-based errors. Also, the results have been illustrated with a map, and the data obtained has been given in a table. In addition, EWT changes according to years were calculated by selecting a point in the region where EWT changes were observed intensely. When the results are analyzed, negative EWT changes have been detected that have increased rapidly in the last few years. Negative values of EWT changes mean that the water body of that area is decreasing. © Author(s) 2022.eninfo:eu-repo/semantics/openAccessCaspian SeaCSRDDK FilterEWTGRACE and GRACE-FOArticle10.51489/tuzal.11525632-s2.0-85215365803