Global modelling of the lithosphere and mantle and explaning geoid signal by merging of tomography derived mantle flow models with full thermal convection models including lateral viscosity variations

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The Earth¿s gravity field and geoid are very sensitive to the density structure and dynamic processes within the Earth that strongly influence its surface. Globally complete and homogenous gravity and geoid models as well as their temporal variations are, being provided by the new satellite missions CHAMP and GRACE with unprecedented accuracy. These data offer a unique opportunity to better understand global Earth structure and dynamics, The new gravity data will be used with other data (seismic P-, S-velocities, surface topography, GPS-derived surface velocities, heat flow) to investigate global Earth structure, to quantitatively describe the underlying dynamic and thermal convection processes, and to model the associated response of the Earth¿s surface. These goals will be achieved by the construction of a global 3D model of the Earth that describes the main properties and dynamics of the mantle and crust. Because global processes strongly influence regional tectonic regimes, special attention will also be placed on cross-scale modelling of time-dependent processes on regional scales such as collision zones and the associated timedependent gravity signals. Thus this project will attempt to explain both the dominating long wavelength contributions of the static gravity field, the weak higher degree regional variations and the very weak temporal variations in terms of geodynamic processes.