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Article
A New Hybrid Method for Estimating Hydrologically Induced Vertical Deformation From GRACE and a Hydrological Model: An Example From Central North America
Journal of Advances in Modeling Earth Systems
  • Makan A. Karegar, University of South Florida
  • Timothy H. Dixon, University of South Florida
  • Jurgen Kusche, University of Bonn
  • Don P. Chambers, University of South Florida St. Petersburg
Document Type
Article
Publication Date
5-1-2018
Keywords
  • GPS,
  • GRACE,
  • loading deformation,
  • hybrid method,
  • Central North America
Digital Object Identifier (DOI)
https://doi.org/10.1029/2017MS001181
Disciplines
Abstract

Hydrologically induced deformation of Earth's surface can be measured with high precision geodetic techniques, which in turn can be used to study the underlying hydrologic process. For geodetic study of other Earth processes such as tectonic and volcanic deformation, or coastal subsidence and its relation to relative sea level rise and flood risk, hydrological loading may be a source of systematic error, requiring accurate correction. Accurate estimation of the hydrologic loading deformation may require consideration of local as well as regional loading effects. We present a new hybrid approach to this problem, providing a mathematical basis for combining local (near field) and regional to global (far field) loading data with different accuracies and spatial resolutions. We use a high‐resolution hydrological model (WGHM) for the near field and GRACE data for the far field. The near field is defined as a spherical cap and its contribution is calculated using numerical evaluation of Green's functions. The far field covers the entire Earth, excluding only the near‐field cap. The far‐field contribution is calculated using a modified spherical harmonic approach. We test our method with a large GPS data set from central North America. Our new hybrid approach improves fits to GPS‐measured vertical displacements, with 25% and 35% average improvement relative to GRACE‐only or WGHM‐only spherical harmonic solutions. Our hybrid approach can be applied to a wide variety of environmental surface loading problems.

Rights Information
Creative Commons Attribution-Noncommercial-No Derivative Works 4.0
Citation / Publisher Attribution

Journal of Advances in Modeling Earth Systems, v. 10, issue 5, p. 1196-1217

Citation Information
Makan A. Karegar, Timothy H. Dixon, Jurgen Kusche and Don P. Chambers. "A New Hybrid Method for Estimating Hydrologically Induced Vertical Deformation From GRACE and a Hydrological Model: An Example From Central North America" Journal of Advances in Modeling Earth Systems Vol. 10 Iss. 5 (2018) p. 1196 - 1217
Available at: http://works.bepress.com/timothydixon/12/