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AGU: Geophysical Research Letters

 

Keywords

  • hydrology deformation
  • GRACE
  • GPS

Index Terms

  • Geodesy and Gravity: Non-tectonic deformation
  • Geodesy and Gravity: Time variable gravity
  • Hydrology: Hydrogeophysics
  • Geodesy and Gravity: Space geodetic surveys
  • Geodesy and Gravity: Integrations of techniques

Abstract

Detecting hydrologic deformation using GRACE and GPS

P. Tregoning

Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia

C. Watson

Surveying and Spatial Science Group, School of Geography and Environmental Studies, University of Tasmania, Hobart, Tasmania, Australia

G. Ramillien

Dynamique Terrestre et Planétaire, UMR5562, CNRS, Toulouse, France

H. McQueen

Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia

J. Zhang

Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia

Hydrological processes cause variations in gravitational potential and surface deformations, both of which are detectable using space geodetic techniques. We computed elastic deformation using continental water load estimates derived from the Gravity Recovery and Climate Experiment and compared to 3D deformation estimated from GPS observations. The agreement is very good in areas where large hydrologic signals occur over broad spatial scales, with correlation in horizontal components as high as 0.9. Agreement is also observed at smaller scales, including across Europe. This suggests that: a) both techniques are perhaps more accurate than previously thought and b) a large percentage of the non-linear variations seen in our GPS time series are most likely related to geophysical processes rather than analysis error. Low correlation at some sites suggests that local processes or site specific analysis errors dominate the GPS deformation estimates rather than the broad-scale hydrologic signals detected by GRACE.

Received 17 April 2009; accepted 2 June 2009; published 7 August 2009.

Citation: Tregoning, P., C. Watson, G. Ramillien, H. McQueen, and J. Zhang (2009), Detecting hydrologic deformation using GRACE and GPS, Geophys. Res. Lett., 36, L15401, doi:10.1029/2009GL038718.

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