| Popis: |
Topographic and topoisostatic reductions of gravity field measurements are important in geodesy and geophysics. Reductions filter high frequencies from gravity which are then used in geoid modelling or investigations of the Earth’s structure. Practical computations of reductions are performed using digital elevation/bathymetric models as input data and some approximation scheme of the Earth’s structure. The main parameters describing the Earth’s structure are crustal, mantle and water density, density contrast, and Moho depths. Traditionally, standard global values for parameters are used which in local areas significantly differ from reality. As Earth’s topography and structure largely varies, it is of interest to know the effects and differences caused by using different input models and parameters describing the Earth’s topography and structure. Results presented in this paper are topographic and topoisostatic corrections on gravity anomalies and geoid undulations calculated for the wider Croatian area using GTOPO30, GMTED2010, GEBCO2014, SRTM15+ and SRTM30+ digital elevation and bathymetric models and several arbitrarily chosen parameters describing the Earth’s structure. The study area is suitable because it includes topographic changes from simple and flat to mountainous and complex terrain. Differences between solutions will point out importance of appropriate selection of the input models and crustal scheme. |
