Institute of Geodesy Research Research Projects
Modeling of mass variations down to small scales (CRC 1128, C05)

Modeling of mass variations down to small scales (CRC 1128, C05)

Led by:  Prof. Dr.-Ing. habil. Jürgen Müller
Team:  Dr.-Ing. Balaji Devaraju, M.Sc. Lars Leßmann
Year:  2014
Funding:  DFG
Is Finished:  yes
Further information

The performance of new sensors and system configurations opens an extended new field of applications, as then also small-scale mass variations in the Earth system can be observed. This project aims at two major objectives that are relevant for the success of geo-Q and support the maximum exploitation of the novel sensor data. First, we will thoroughly demonstrate the great potential of the new technology using mass variations in the Fennoscandian land uplift area, which are dominated by Glacial Isostatic Adjustment (GIA). We will derive a mainly data-driven model of the relevant mass changes in Fennoscandia, which are related to GIA, atmosphere and hydrology including variations of ground water and of the Baltic Sea. This model, added by the data set of Gruber et al. (2011) to also cover long-wavelength parts of the gravity field, will be applied to estimate how sensitive the observed satellite signals are with respect to various geophysical contributions and to uncertainties in the model parts. With our model that shall be supported by the novel satellite and terrestrial gravimetry data in future, we will also help to constrain the small-scale geodynamic transition zones (GIA forebulge) and to understand changes in small hydrological basins such as the Baltic Sea. Here, a further research task will cover the separation of various signal parts from the integral satellite observations (backward modeling), especially in our region but also – indirectly – in other areas.

The second objective of this project addresses the problem of de-aliasing of satellite gravity data, i.e. the reduction of high-frequency mass variations during data processing. Uncertainties in the modeling of daily atmospheric or non-modeled hydrological mass changes smear into the monthly global gravity field solutions. We will study if regional models can help in de-aliasing satellite observations, especially our model of mass variations in Fennoscandia. This may even allow the recovery of all global geopotential coefficients with higher accuracy. De-aliasing shall further be improved by applying modified analysis procedures using the knowledge about the expected signal.

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