Current Research Projects – Institute of Geodesy

Gravimetric Tides and Gravity Currents in the North Sea

The research group is investigating the gravity and deformation (tilt) effect caused by time variations of the mass distribution in the atmosphere and in the sea. It has to be distinguished between the direct Newtonian attraction effects and indirect loading effects. The latter part is accompanied by a vertical shift and a tilt of the sea floor as well as the land surface, especially along the coast or on islands, because of the elasticity of the solid Earth’s crust. Such a vertical ground displacement is associated with an absolute height change of the gravimeter w.r.t. the geocenter. The combined observation of gravity and tilt changes allows the separation of signals due to attraction and load deformation.

Leaders: Dr.-Ing. Ludger Timmen, Dr. Adelheid Weise

Team: Dr.-Ing. Ludger Timmen, Dr. Adelheid Weise

Year: 2018

Sponsors: IfE, Germany’s Excellence Strategy – EXC-2123 “QuantumFrontiers”

Lifespan: 2018-2021

Gravimetry at Zugspitze and Wank Mountains (Bavarian Alps, Germany)

The geodetic monitoring of variations caused by Alpine orogency and the diminishing permafrost are undertaken with gravimetric as well as geometric techniques. In addition to IfE (absolute and relative gravimetry, levelling), the Bavarian Academy of Sciences and Humanities (GNSS, levelling, relative gravimetry), the Institute of Astronomical and Physical Geodesy - Technical University of Munich (relative gravimetry) and the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences (superconducting gravimetry, GNSS permanent geodynamic observatory on the Zugspitze) are involved in the cooperation.

Leaders: Dr.-Ing. Ludger Timmen

Year: 2018

Sponsors: IFE, Germany’s Excellence Strategy – EXC-2123 “QuantumFrontiers”, GFZ Potsdam, TU München, Bayerische Akademie der Wissenschaften

Gravimetric reference network for a 10m atom interferometer

The Very Long Baseline Atom Interferometer (VLBAI) at the Hannover Institute for Technology (HITec) is a physics instrument in which experiments on the interferometry of atoms can be carried out over a free-fall distance of about 10m. These experiments are mainly used for fundamental physics, but gravimetric measurements can also be performed. Due to the large fall distance and the resulting long fall time of the atoms, a future accuracy in the range of 1 nm/s² is anticipated. With classical transportable absolute gravimeters, however, some tens nm/s² are achieved. The VLBAI could therefore be a reference for classical gravimeters. For these experiments and for the evaluation of the error budget, however, knowledge of the local gravitational field is necessary. This will be determined in parallel to the installation of the large-scale instrument and further on by gravimetric measurements and forward modelling.

Leaders: Dr.-Ing. Manuel Schilling, Dr.-Ing. Ludger Timmen

Team: Dr.-Ing. Manuel Schilling, Dr.-Ing. Ludger Timmen

Year: 2017

Sponsors: IfE, SFB-1128, EXC-2123 "QuantumFrontiers"

Lifespan: 2017-2025

A mobile absolute gravimeter based on atom interferometry for highly accurate point observations

Atom interferometers have demonstrated a high sensitivity to inertial forces. The Gravimetric Atom Interferometer (GAIN), developed at Humboldt-Universität zu Berlin, is a mobile atom interferometer based on interfering ensembles of laser-cooled Rb-87 atoms in an atomic fountain configuration. In the continued development state-of-the-art superconductiong gravimeters and laser-interferometer based absolute gravimeters are used for comparisons with and the characterization of GAIN.

Leaders: Prof. Dr.-Ing. Jürgen Müller

Team: M. Sc. Manuel Schilling

Year: 2012

Sponsors: DFG