Abstract
We adopt Poisson wavelets for regional gravity field recovery using data acquired from various observational techniques; the method combines data of different spatial resolutions and coverage, and various spectral contents and noise levels. For managing the ill-conditioned system, the performances of the zero- and first-order Tikhonov regularization approaches are investigated. Moreover, a direct approach is proposed to properly combine Global Positioning System (GPS)/leveling data with the gravimetric quasi-geoid/geoid, where GPS/leveling data are treated as an additional observation group to form a new functional model. In this manner, the quasi-geoid/geoid that fits the local leveling system can be computed in one step, and no post-processing (e.g., corrector surface or least squares collocation) procedures are needed. As a case study, we model a new reference surface over Hong Kong. The results show solutions with first-order regularization are better than those obtained from zero-order regularization, which indicates the former may be more preferable for regional gravity field modeling. The numerical results also demonstrate the gravimetric quasi-geoid/geoid and GPS/leveling data can be combined properly using this direct approach, where no systematic errors exist between these two data sets. A comparison with 61 independent GPS/leveling points shows the accuracy of the new geoid, HKGEOID-2016, is around 1.1 cm. Further evaluation demonstrates the new geoid has improved significantly compared to the original model, HKGEOID-2000, and the standard deviation for the differences between the observed and computed geoidal heights at all GPS/leveling points is reduced from 2.4 to 0.6 cm. Finally, we conclude HKGEOID-2016 can be substituted for HKGEOID-2000 for engineering purposes and geophysical investigations in Hong Kong.Graphical abstract.
Highlights
High-resolution regional gravity field recovery is of considerable importance for surveying and mapping, and for research fields, such as oceanography, geophysics, and geodynamics (Kuroishi 2009; Panet et al 2011; Shih et al 2015).Typically, middle- and short-wavelength gravity field signals down to a few kilometers are extracted from high-resolution ground-based measurements, e.g., terrestrial and shipborne gravity data, which are only available in geographically limited regions (Wang et al 2012; Odera and Fukuda 2014; Lieb et al 2016)
Results from the Global Positioning System (GPS)/leveling data for groups I and II only provide the internal agreement between the modeled geoid and GPS/leveling data, and cannot be used for assessing the solution quality because they are used as observations for modeling
The numerical results show solutions with first-order regularization provide better results, where the accuracy of the local solution increases by 0.2 cm compared to that obtained from zero-order regularization
Summary
High-resolution regional gravity field recovery is of considerable importance for surveying and mapping, and for research fields, such as oceanography (understanding ocean circulation and currents), geophysics (investigating the structure of seismic activities and the lithosphere), and geodynamics (Kuroishi 2009; Panet et al 2011; Shih et al 2015).Typically, middle- and short-wavelength gravity field signals down to a few kilometers are extracted from high-resolution ground-based measurements, e.g., terrestrial and shipborne gravity data, which are only available in geographically limited regions (Wang et al 2012; Odera and Fukuda 2014; Lieb et al 2016). Wu et al Earth, Planets and Space (2017) 69:34 of GGMs. developing various observational techniques, e.g., GPS, airborne gravimetric measurements, and satellite altimetry missions, can further improve regional gravity fields (Hwang et al 2006; Jiang and Wang 2016; Wu and Luo 2016). Developing various observational techniques, e.g., GPS, airborne gravimetric measurements, and satellite altimetry missions, can further improve regional gravity fields (Hwang et al 2006; Jiang and Wang 2016; Wu and Luo 2016) Combined, these data sets form a solid basis for modeling high-resolution and high-quality regional gravity fields. These data sets form a solid basis for modeling high-resolution and high-quality regional gravity fields These data have heterogeneous spatial coverage and resolutions, various error characteristics, and different spectral contents, which make their use an open issue. The aim of this study is to adopt an approach that combines heterogeneous data and extracts different spectral contents from various observational techniques for regional gravity field recovery
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
