Christian Voigt

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• Doctor of Engineering
• Senior Scientist at GFZ Helmholtz Centre for Geosciences

Plain Language Summary This study addresses the challenge of accurately computing the amount of water stored in snow (known as snow water equivalent or SWE) in mountainous areas, which is important for managing water resources. Typically, there are no tools that can measure SWE across large areas in complex high alpine surroundings, only at specifi...

The lack of accurate information on the snow water equivalent (SWE) including its spatio-temporal variations in mountain catchments remains a key problem in snow hydrology and water resources management. This is partly because there is no sensor to measure SWE beyond local scale. At Mt. Zugspitze, Germany, a superconducting gravimeter senses the gr...

Plain Language Summary Terrestrial gravimetry is a technique to monitor temporal variations of the gravity acceleration at the Earth's surface that are induced by mass variations and deformations caused by a large number of geophysical effects on very different temporal and spatial scales. Current applications of high social relevance are the estim...

The superconducting gravimeter GWR iGrav 047 has been installed on the small offshore island of Heligoland in the North Sea approximately at sea level with the overall aim of high-accuracy determination of regional tidal and non-tidal ocean loading signals. For validation, a second gravimeter (gPhoneX 152) has been setup within a gravity gradiomete...

We employ the barotropic, data-unconstrained ocean tide model TiME to derive an atlas for degree-3 tidal constituents including monthly to terdiurnal tidal species. The model is optimized with respect to the tide gauge data set TICON-td that is extended to include the respective tidal constituents of diurnal and higher frequencies. The tide gauge v...

GFZ (German Research Centre for Geosciences) set up the Zugspitze Geodynamic Observatory Germany with a worldwide unique installation of a superconducting gravimeter at the summit of Mount Zugspitze on top of the Partnach spring catchment. This high alpine catchment is well instrumented, acts as natural lysimeter and has significant importance for...

The Zugspitze Geodynamic Observatory Germany has been set up with a worldwide unique installation of a superconducting gravimeter at the summit of Mount Zugspitze. With regard to hydrology, this karstic high-alpine site is largely dominated by high precipitation amounts and a long seasonal snow cover period with significant importance for water sup...

In 2004, first absolute gravity (AG) measurements were performed on the top of Mt. Zugspitze (2 sites) and at the foot (1 site) and top (1 site) of Mt. Wank. Mt. Wank (summit height 1780 m) and Mt. Zugspitze (2960 m) are about 15 km apart from each other and belong geologically to different parts of the Northern Limestone Alps. Bridging a time span...

In 2004, first absolute gravity (AG) measurements were performed on the mountain tops of Mt. Zugspitze (2 sites) and Mt. Wank (1 site), and at the Wank foot (1 site). Wank (summit height 1780 m) and Zugspitze (2960 m) are about 20 km apart from each other and belong geologically to different parts of the Northern Limestone Alps. Bridging a time spa...

High spatial and temporal resolution of gravity observations allows quantifying and understanding mass changes in volcanoes, geothermal or other complex geosystems. For this purpose, accurate gravity meters are required. However, transport of the gravity meters to remote study areas may affect the instrument's performance. In this work, we analyse...

Climate change is broadly discussed due to water level rise almost worldwide. Additionally, ocean- related risks driven by atmospheric dynamics are amplified, as tidal amplitudes in coastal areas and storm surges, which threaten coastal areas and the unique Wadden Sea in the German Bight. Investigations of the oceans in general and of the North Se...

We carried out a 26-day comparison of five simultaneously operated optical clocks and six atomic fountain clocks located at INRIM, LNE-SYRTE, NPL and PTB by using two satellite-based frequency comparison techniques: broadband Two-Way Satellite Time and Frequency Transfer (TWSTFT) and Global Positioning System Precise Point Positioning (GPS PPP). Wi...

Hidden matter that interacts only gravitationally would oscillate at characteristic frequencies when trapped inside of Earth. For small oscillations near the center of the Earth, these frequencies are around 300 μHz. Additionally, signatures at higher harmonics would appear because of the non-uniformity of Earth’s density. In this work, we use data...

We present the activities and improvements of the International Geodynamics and Earth Tide Service (IGETS) over the last four years. IGETS collects, archives and distributes long time series from geodynamic sensor, in particular superconducting gravimeter data currently from more than 40 stations and 60 different sensors. In addition to the raw 1-s...

Hidden matter that interacts only gravitationally would oscillate at characteristic frequencies when trapped inside of Earth. For small oscillations near the center of the Earth, these frequencies are around 300 $\mu$Hz. Additionally, signatures at higher harmonics would appear because of the non-uniformity of Earth's density. In this work, we use...

We carried out a 26-day comparison of five simultaneously operated optical clocks and six atomic fountain clocks located at INRIM, LNE-SYRTE, NPL and PTB by using two satellite-based frequency comparison techniques: broadband Two-Way Satellite Time and Frequency Transfer (TWSTFT) and Global Positioning System Precise Point Positioning (GPS PPP). Wi...

We discuss the relation between atomic clocks and gravity from two perspectives: gravity potential measurements for optical clock comparisons and contributions to international timescales and, conversely, the measurement of gravity potential differences using optical clocks.

The advent of novel measurement instrumentation can lead to paradigm shifts in scientific research. Optical atomic clocks, due to their unprecedented stability and uncertainty, are already being used to test physical theories and herald a revision of the International System of units (SI). However, to unlock their potential for cross-disciplinary a...

The frequency stability and uncertainty of the latest generation of optical atomic clocks is now approaching the one part in \(10^{18}\) level. Comparisons between earthbound clocks at rest must account for the relativistic redshift of the clock frequencies, which is proportional to the corresponding gravity (gravitational plus centrifugal) potenti...

The advent of novel measurement instrumentation can lead to paradigm shifts in scientific research. Optical atomic clocks, due to their unprecedented stability and uncertainty, are already being used to test physical theories and herald a revision of the International System of units (SI). However, to unlock their potential for cross-disciplinary a...

The latest generation of optical atomic clocks is approaching the level of one part in 1018 in terms of frequency stability and uncertainty. For clock comparisons and the definition of international time scales, a relativistic redshift effect of the clock frequencies has to be taken into account at a corresponding uncertainty level of about 0.1 m(2...

The International Geodynamics and Earth Tide Service (IGETS) was established in 2015 by the International Association of Geodesy (IAG). IGETS continues the activities of the Global Geodynamics Project (GGP, 1997-2015) to provide support to geodetic and geophysical research activities using superconducting gravimeter data within the context of an in...

An International Geodynamics and Earth Tide Service (IGETS) was established in 2015 by the International Association of Geodesy IAG. IGETS continues the activities of the Global Geodynamics Project (GGP) between 1997 and 2015 to provide support to geodetic and geophysical research activities using superconducting gravimeter (SG) data within the con...

The fifth release of global gravity field models (GGMs) from the GOCE mission published in mid-2014 are based on observation data from the whole mission lifetime. High precision gravity field data sets in Germany are utilized to validate the GOCE GGMs of the fourth and fifth release processed by the time-wise (TIM) and the direct approach (DIR) as...

High-precision terrestrial gravity field data sets in Germany and Europe are utilized to validate recent global gravity field models (GGMs), emphasizing the progress with respect to the latest GOCE GGM releases. The agreement between the release 3 GOCE GGMs and terrestrial data up to degree and order 200 is about 5.5 cm for height anomalies, 1.7 mG...

A new collaborative European project “International timescales with optical clocks” (ITOC) aims to tackle the key challenges that must be addressed prior to a redefinition of the SI second. A coordinated programme of comparisons will be carried out between European optical clocks developed in five different laboratories, enabling their performance...

The validation of GOCE products is one of the main objectives within the framework of the German REAL GOCE project. Within the work package "GOCE Cal/Val, Quasigeoid and Height System", global gravity field models are evaluated by various terrestrial data sets in Germany. In this contribution, the focus is on the evaluation of global gravity field...

Within the next few years, improved high-resolution global gravity field models are anticipated from the GOCE mission. The expected accuracies are about 1–2cm in terms of geoid undulations and 1 mGal for gravity, both at a resolution of about 100km. Then, from a combination of the GOCE based global gravity field models (expected to be available up...

In the context of a GOCE regional validation and combination experiment in Germany, a work package within the framework of the GOCE-GRAND II project, gravity observations, vertical deflections and GPS/levelling data are collected as independent data sets. The observation of absolute gravity values is carried out by the Bundesamt für Kartographie un...

2008) Hochpräzise Bestimmung eines astrogeodätischen Quasigeoidprofils im Harz für die Validierung des Quasigeoidmodells GCG05. Zeitschrift für Vermessungswesen (zfv) 133: 108-119. Zusammenfassung Im vorliegenden Beitrag wird die Messung, Berech-nung und Analyse eines hochpräzisen astrogeodätischen Quasigeoidprofils zur Validierung des gravimetrisc...

This paper deals with the determination of a high-precision astrogeodetic quasigeoid profile for the validation of the gravimetric quasigeoid model GCG05 in the Harz mountains in Northern Germany. The Hannover Digital Zenith Camera System TZK2-D was used for the observation of new vertical deflection data at densely spaced stations (500-600 m avera...

Within the framework of the GOCE- GRAND II project and in cooperation with the Bundesamt für Kartographie und Geodäsie (BKG), it is planned to validate the GOCE gravity field models by independent terrestrial data sets. Besides GPS and levelling data, gravity and terrain data shall be combined with a global spherical harmonic model to provide an in...