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Your search keyword '"Mayer-Guerr, T"' showing total 5 results
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5 results on '"Mayer-Guerr, T"'

1. Evaluating long-term water storage trends in small catchments and aquifers from a joint inversion of 20 years of GRACE/GRACE-FO mission data.

Author

Kvas, A, Boergens, E, Dobslaw, H, Eicker, A, Mayer-Guerr, T, and Güntner, A

Subjects
GRAVIMETRY, SPATIAL resolution, WATER storage, REMOTE sensing, SATELLITE geodesy, GRAVITY, WATERSHEDS, AQUIFERS
Abstract

More than 20 yr of measurement data of the gravity missions GRACE (Gravity Recovery And Climate Experiment) and GRACE-FO (GRACE-Follow-On) allow detailed investigations of long-term trends in continental terrestrial water storage (TWS). However, the spatial resolution of conventional GRACE/GRACE-FO data products is limited to a few hundred kilometres which restrains from investigating hydrological trends at smaller spatial scales. In this study GRACE and GRACE-FO data have been used to calculate TWS trends with maximized spatial resolution. Conventionally, GRACE/GRACE-FO is presented as a series of either unconstrained gravity fields post-processed with spatial low pass filters or constrained inversions commonly known as Mascon products. This paper demonstrates that both approaches to suppress spatially correlated noise are mathematically equivalent. Moreover, we demonstrate that readily inverting all available sensor data from GRACE/GRACE-FO for a single TWS trend map, together with annual variations and a mean gravity field, provides additional spatial detail not accessible from the standard products. The variable trade-off between spatial and temporal resolution as a unique feature of satellite gravimetry allows for gravity products that are tailored towards specific geophysical applications. We show additional signal content in terms of long-term water storage trends for four dedicated examples (Lake Victoria, Northwest India, Bugachany Reservoir and High Plains Aquifer) for which external information from other remote sensing instruments corroborates the enhanced spatial resolution of the new mean-field trend product. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Unified approach to exploit the full potential of ocean tide models for space geodetic techniques

Author

Mayer-Guerr, T., Oehlinger, F., Sulzbach, R., and Dobslaw, H.

Abstract

The influence of ocean tides plays a major role for geodetic space methods in the modeling of satellite orbits, Earth rotation, and short-period station motions.Current ocean tide models are published with a large number of individual constituents that are representative for the entire tidal spectrum. The analysis requires interpolation of the constituents onto the spectrum using admittance theory. The application of admittance is non-trivial, as it explicitly and implicitly refers to historical conventions that are hard to retrace for users. Further linear admittance theory is non-unique and requires some insight into the principles of ocean tidal dynamics.Nonetheless, the error-prone implementation of admittance is mostly left to the user, which can easily induce confusion and errors. For example, the IERS2010 conventions describe only one method for the outdated FES2004 model that does not apply directly to current models. While there is a conventional routine for calculating the ocean loading displacement, it ignores recent developments and therefore does not exploit the full potential of current ocean tide models.In this presentation, a unified approach is presented for discussion to exploit the full potential of current ocean tide models in satellite orbit calculation and for station displacements. This approach aims to set up a framework for tidal correction that is userfriendly, model-independent, and applies to many geophysical observables.

Published
2023

4. Bayesian Inference in Satellite Gravity Inversion

Author

Kis, K. I, Taylor, Patrick T, Wittmann, G, Kim, Hyung Rae, Torony, B, and Mayer-Guerr, T

Subjects
Spacecraft Design, Testing And Performance
Abstract

To solve a geophysical inverse problem means applying measurements to determine the parameters of the selected model. The inverse problem is formulated as the Bayesian inference. The Gaussian probability density functions are applied in the Bayes's equation. The CHAMP satellite gravity data are determined at the altitude of 400 kilometer altitude over the South part of the Pannonian basin. The model of interpretation is the right vertical cylinder. The parameters of the model are obtained from the minimum problem solved by the Simplex method.

Published
2005

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