Abstract

Abstract. A multilayer approach is set up for local gravity field recovery within the framework of multi-resolution representation, where the gravity field is parameterized as the superposition of multiple layers of Poisson wavelets located at different depths beneath the Earth's surface. The layers are designed to recover gravity signals at different scales, where the shallow and deep layers mainly capture the short- and long-wavelength signals, respectively. The depths of these layers are linked to the locations of different anomaly sources beneath the Earth's surface, which are estimated by wavelet decomposition and power spectrum analysis. For testing the performance of this approach, a gravimetric quasi-geoid model over the North Sea, QGNSea V1.0, is modeled and validated against independent control data. The results show that the multilayer approach fits the gravity data better than the traditional single-layer approach, particularly in regions with topographical variation. An Akaike information criterion (AIC) test shows that the multilayer model obtains a smaller AIC value and achieves a better balance between the goodness of fit of data and the simplicity of the model. Further, an evaluation using independent GPS/leveling data tests the ability of regional models computed from different approaches towards realistic extrapolation, which shows that the accuracies of the QGNSea V1.0 derived from the multilayer approach are better by 0.4, 0.9, and 1.1 cm in the Netherlands, Belgium, and parts of Germany, respectively, than that using the single-layer approach. Further validation with existing models shows that QGNSea V1.0 is superior with respect to performance and may be beneficial for studying ocean circulation between the North Sea and its neighboring waters.

Highlights

  • Knowledge of the Earth’s gravity field at the regional scale is crucial for a variety of applications in geodesy

  • Regional gravity field determination is typically conducted within the framework of the remove–compute–restore (RCR) methodology (Sjöberg, 2005), where long-wavelength signals are often recovered by satellite-only global geopotential models (GGMs) derived from dedicated satellite gravity missions such as the Gravity Field and Climate Experiment (GRACE; Tapley et al, 2004) and Gravity Field and SteadyState Ocean Circulation Explorer (GOCE; Rummel et al, 2002)

  • A multilayer approach for gravity field recovery at the regional scale, within the framework of multi-resolution representation, is developed, where the residual gravity field is parameterized as the superposition of the multiple layers of Poisson wavelets located at different depths beneath the Earth’s surface

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Summary

Introduction

Knowledge of the Earth’s gravity field at the regional scale is crucial for a variety of applications in geodesy. Panet et al (2011) extended the approach developed by Chambodut et al (2005) by applying a domain decomposition approach to defining the hierarchical subdomains of wavelets at different scales; this enabled the splitting of a large problem into smaller ones The results of these studies show that the multiscale approach using SRBFs has a good potential for gravity field recovery. In this study, inspired by the power spectral analysis of local gravity signals, we develop new parameterizations of the SRBF network within the MRR approach In this approach, multiple layers are linked to the anomaly sources at different depths beneath the Earth’s surface, and the aim is to recover the signals with different spectral contents.

Study area and data
Multilayer approach
Numerical results and discussion
Wavelet analysis of local gravity signals
Regional solution and its validation
Conclusions
Full Text
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