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  • 1
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    Hydrometeorological and gravity signals at the Argentine-German Geodetic Observatory (AGGO) in La Plata (2019)
    In:  Earth System Science Data
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    Publication Date: 2020-02-12
    Type: info:eu-repo/semantics/article
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  • 2
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    Modeling gravimetric signatures of third-degree ocean tides and their detection in superconducting gravimeter records (2022)
    In:  Journal of Geodesy
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    Publication Date: 2023-01-30
    Description: 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 validation shows a root-mean-square (RMS) deviation of 0.9–1.3 mm for the individual species. We further model the load tide-induced gravimetric signals by two means (1) a global load Love number approach and (2) evaluating Greens-integrals at 16 selected locations of superconducting gravimeters. The RMS deviation between the amplitudes derived using both methods is below 0.5 nGal (1 nGal =0.01nms2) when excluding near-coastal gravimeters. Utilizing ETERNA-x, a recently upgraded and reworked tidal analysis software, we additionally derive degree-3 gravimetric tidal constituents for these stations, based on a hypothesis-free wave grouping approach. We demonstrate that this analysis is feasible, yielding amplitude predictions of only a few 10 nGal, and that it agrees with the modeled constituents on a level of 63–80% of the mean signal amplitude. Larger deviations are only found for lowest amplitude signals, near-coastal stations, or shorter and noisier data sets.
    Type: info:eu-repo/semantics/article
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  • 3
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    Hydrometeorological and gravity data from the Argentine-German Geodetic Observatory in La Plata (2018)
    GFZ Data Services
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    Publication Date: 2020-02-12
    Description: The data set contains hydrological, meteorological and gravity time series collected at Argentine-German Geodetic Observatory (AGGO) in La Plata, Argentina. The hydrological series include soil moisture, temperature, electric conductivity, soil parameters, and groundwater variation. The meteorological time series comprise air temperature, humidity, pressure, wind speed, solar short- and long-waver radiation, and precipitation. The observed hydrometeorological parameters are extended by modelled value of evapotranspiration and water content variation in the zone between deepest soil moisture sensor and the groundwater level. Gravity products include large-scale hydrological, oceanic as well as atmospheric effects. These gravity effects are furthermore extended by local hydrological effects and gravity residuals suitable for comparison and evaluation of the model performance. Provided are directly observed values denoted as Level 1 product along with pre-processed series corrected for known issues (Level 2). Level 3 products are model outputs acquired using Level 2 data. The maximal temporal coverage of the data set ranges from May 2016 up to November 2018 with some exceptions for sensors and models set up in May 2017. The data set is organized in a database structure suitable for implementation in a relational database management system. All definitions and data tables are provided in separate text files allowing for traditional use without database installation.
    Language: English
    Type: info:eu-repo/semantics/workingPaper
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  • 4
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    Evaluation of the AQG-B10 absolute quantum gravimeter for field measurements (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
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    Publication Date: 2023-06-28
    Description: Falling corner cube gravimeters (FCCG) pose the current state-of-the-art instruments for absolute terrestrial gravimetry. However, already in the early 1990s, experimental quantum gravimeters have been demonstrated: a fundamentally different principle for measuring gravity based on probing the free-fall trajectory of ultracold atoms via quantum matter wave interference. In recent years, the community's interest in quantum gravimeters has strongly increased as they have progressed from experimental prototypes towards commercially available instruments intended for end-users in geodetic applications.The commercially available iXblue Absolute Quantum Gravimeter (AQG) B-series instrument is a field-compatible successor to the A-series AQG, which is restricted to indoor use. Here, we present our first results of evaluating the AQG-B10 instrument for lab and field operation in BKG’s routine measurement campaigns. We assess the instrument precision, stability, accuracy and reproducibility based on comparison measurements at the Geodetic Observatory Wettzell employing a continuous gravity reference function. This reference is derived from the combination of measurements with the Micro-g LaCoste FG5 FCCG, currently dominating absolute gravimetry, with highly precise superconducting gravimeters, and is linked to the EURAMET.M.G-K3 regional comparison of absolute gravimeters. Moreover, we compare the AQG-B10 to the Micro-g LaCoste A10 FCCG, the current state-of-the-art instrument for absolute field measurements.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 5
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    Estimation of the Argentinean vertical datum parameter with respect to the International Height Reference System (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-07-19
    Description: One of the current goals of the Global Geodetic Observing System (GGOS) through the International Association of Geodesy (IAG) is the unification of the existing classical vertical datums towards the materialization of the International Height Reference System (IHRS). In order to achieve this goal, it is possible to compute the mean geopotential offset between the equipotential surface of the Earth’s gravity field realized by the conventional value Wo= 62 636 853.4 m〈sup〉2〈/sup〉s〈sup〉-2〈/sup〉 of the IHRS and the unknown geopotential value of the local vertical datum. This offset is known as the vertical datum parameter. In this study, the determination of the discrepancy between the Argentinean National Vertical Reference System 2016 (SRVN16) over the continental part of Argentina and the IHRS is presented. With this objective, the zero-height geopotential value for the Argentinean Local Vertical Datum W0LVD was determined based on two approaches: 1) Using high-quality GNSS/Levelling data and a local gravimetric geoid model; and 2) Combining orthometric heights from SRVN16 with geoid heights through a Least Squares adjustment, integrating terrestrial gravity data for a specific area in Argentina. In both approaches, the local gravimetric geoid was computed by the well-known remove-compute-restore technique and applying a Fourier representation of Stokes’ integral formula. Preliminary analysis was carried out in a flat area in Buenos Aires province due to availability of high-quality data, gravity observations and benchmarks with GNSS/Levelling-derived heights, all located near the tide gauge station used to define the Argentinean Vertical Datum.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 6
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    Update of the Atmospheric attraction computation service (Atmacs) for high-precision terrestrial gravity observations (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-11-15
    Description: The Atmospheric attraction computation service (Atmacs) provides atmospheric corrections for terrestrial high-precision gravity time series based on operational weather models of the German Weather Service (DWD). In Atmacs, Newtonian attraction and deformation contributions to loading are computed separately. The attraction component benefits from the discrete 3D distribution of air mass around the station, while deformation effects are derived from surface atmospheric pressure changes assuming that the oceans behave as a perfect Inverse Barometer (IB).Several improvements in the modelling approach of Atmacs are presented. A revision of the IB hypothesis implementation revealed that the attraction component over oceans is overestimated. A modification of the IB implementation not only resolves this issue but further enhances the compatibility between the atmospheric modelling and ocean models. This allows to complement Atmacs with non-tidal ocean loading (NTOL) effects, here based on the Max-Plank-Institute for Meteorology Ocean Model (MPIOM). These updates allow for a consistent combination of atmospheric and ocean models and a more efficient reduction of the gravity time series.Finally, we evaluate atmospheric corrections derived from both meteorological models currently used by Atmacs: the global and the European solutions of the Icosahedral Nonhydrostatic (ICON) model. In the case of the regional model, non-regional contributions are accounted from the global solution. This comparison is performed for several stations located in Europe, with emphasis on the estimation of tidal parameters and the reduction of gravity residuals.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 7
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    Combining atmospheric and non-tidal ocean loading effects to correct high precision gravity time-series (2024)
    In:  Geophysical Journal International
    Details
    Publication Date: 2024-01-09
    Description: In modelling atmospheric loading effects for terrestrial gravimetry, state-of-the-art approaches take advantage of numerical weather models to account for the global 3-D distribution of air masses. Deformation effects are often computed assuming the Inverse Barometer (IB) hypothesis to be generally valid over the oceans. By a revision of the IB assumption and its consequences we show that although the seafloor is not deformed by atmospheric pressure changes, there exists a fraction of ocean mass that current modelling schemes are usually not accounting for. This causes an overestimation of the atmospheric attraction effect over oceans, even when the dynamic response of the ocean to atmospheric pressure and wind is accounted through dynamic ocean models. This signal can reach a root mean square variability of a few nm s−2, depending on the location of the station. We therefore test atmospheric and non-tidal ocean loading effects at five superconducting gravimeter (SG) stations, showing that a better representation of the residual gravity variations is found when Newtonian attraction effects due to the IB response of the ocean are correctly considered. A sliding window variance analysis shows that the main reduction takes place for periods between 5 and 10 d, even for stations far away from the oceans. Since periods of non-tidal ocean mass variability closely resemble atmospheric signals recorded by SGs, we recommend to directly incorporate both an ocean component together with the IB into services that provide weather-related corrections for terrestrial gravimetry.
    Language: English
    Type: info:eu-repo/semantics/article
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