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Abstract:
The gravity field plays a crucial role in Earth System Sciences. Currently available static global gravity field models are limited in resolution due to the band-limited spectral content of the input data from satellite observations and gravity measurements on the Earth’s surface. Such models are complemented beyond their current limits using high-resolution digital elevation models (DEMs) and density estimates. At GFZ, we are interested in developing such high-resolution topographic models to enhance the representation of static global gravity field models such as EIGEN-6C4. Our preliminary study expanded the model representation of EIGEN-6C4 up to d/o 5400 using Earth2014 and four density values estimated for rock, ocean, lake and ice. Moreover, we tested the impact of different shell thicknesses to the numerical stability and computation time. Current study is a continuation of our previous activities and summarises the first results of a DFG project GRAV4GEO (GRAVitational field modelling of Earth’s topography For GEOdetic and GEOphysical applications). We aim to improve the performance of our preliminary model ROLI_EllApprox_SphN_3660 further via introducing improved DEM and laterally varying density estimations and optimized methodology. Our preferred DEM model will be a product of combined solutions from TanDEM-X 90 m and other state-of-the-art DEM models developed/improved recently. Moreover, we aim to introduce a 3D density estimation globally. The new model is expected to enhance our preliminary model and contribute to the accurate representation of very high-resolution static global gravity field modelling.
