Characterization and stabilization of the downward continuation problem for airborne gravity data

Characterization and stabilization of the downward continuation problem for airborne gravity data

Li, X. (National Oceanic and Atmospheric Administration)
Huang, J. (Natural Resources Canada)
Klees, R. (TU Delft Physical and Space Geodesy)
Forsberg, R. (Technical University of Denmark)
Willberg, M. (Technische Universität München)
Slobbe, D.C. (TU Delft Physical and Space Geodesy)
Hwang, C. (National Yang Ming Chiao Tung University, Hsinchu)
Pail, R. (Technische Universität München)

2022

In this study, we compare six commonly used methods for the downward continuation of airborne gravity data. We consider exact and noisy simulated data on grids and along flight trajectories and real data from the GRAV-D airborne campaign. We use simulated and real surface gravity data for validation. The methods comprise spherical harmonic analysis, least-squares collocation, residual least-squares collocation, least-squares radial basis functions, the inverse Poisson method and Moritz’s analytical downward continuation method. We show that all the methods perform similar in terms of surface gravity values. For real data, the downward continued airborne gravity values are used to compute a geoid model using a Stokes-integral-based approach. The quality of the computed geoid model is validated using high-quality GSVS17 GPS-levelling data. We show that the geoid model quality is similar for all the methods. However, the least-squares collocation approach appears to be more flexible and easier to use than the other methods provided that the optimal covariance function is found. We recommend it for the downward continuation of GRAV-D data, and other methods for second check.

Airborne gravimetry
Downward continuation
Geoid
Gravity

http://resolver.tudelft.nl/uuid:e3abf758-c06c-4057-87f5-67d0c54292f1

https://doi.org/10.1007/s00190-022-01607-y

2023-07-01

0949-7714

Journal of Geodesy, 96 (4)

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2022 X. Li, J. Huang, R. Klees, R. Forsberg, M. Willberg, D.C. Slobbe, C. Hwang, R. Pail