Estimation and analysis of physical height changes using satellite gravimetry: Case studies in Turkey and Greenland

The continuity of the water cycle in the ocean, atmosphere and continents leads to rapid changes in the Earth's gravity field. These changes can only be detected locally with terrestrial gravity measurements and require high effort and cost. With artificial satellites, it has become quite easy to detect the time variable gravity field on a global scale, and studies on producing a global geopotential model have been increased. GRACE (Gravity Recovery and Climate Experiment) (2002-2017) satellite mission that is developed for this purpose contributes greatly to understanding the Earth's dynamic system with its satellite gravimetry technology. Since 2002, GRACE satellite mission, which has a very successful system in monitoring many phenomena such as the effects of change in global climate systems on the Earth, terrestrial water cycle, sea level changes and glacial movements, has shed light on all studies regarding the time-variable gravity and its functionals with the high-resolution data it offers. With this mission, physical heights, which are very important in Earth sciences and indispensable for engineering projects, can be determined with higher accuracy, and it is also possible to monitor time-dependent changes. Determining and modeling the time-dependent physical height changes is required for updating and modernizing height systems. In this study, physical height changes were investigated using the GRACE global geopotential model and WGHM in the area of Turkey and Greenland. In Turkey, the Green's function and Terzaghi principle approach have been implemented. In both study areas, the obtained physical height changes were analyzed and modeled by seasonal decomposition method and principal component analysis/empirical orthogonal function method. Furthermore, PHCSOFT has been developed in the C/C++ programming language, which enables users to estimate physical height changes, geoid height changes and temporal changes of aseismic surface displacements at any point and plot time series.