1887
Volume 11 Number 2
  • ISSN: 1569-4445
  • E-ISSN: 1873-0604

Abstract

ABSTRACT

In many hydrological applications, ground‐wave velocity measurements are increasingly used to map and monitor shallow soil water content. In this study, we propose an automated spectral velocity analysis method to determine the direct ground‐wave (DGW) velocity from common midpoint (CMP) or multi‐offset ground‐penetrating radar (GPR) data. The method introduced in this paper is a variation of the well‐known spectral velocity analysis for seismic and GPR reflection events where velocity spectra are computed using different coherency measures along hyperbolas following the normal moveout model. Here, the unnormalized cross‐correlation is computed between waveforms across data gathers that are corrected with a linear moveout equation using a predefined range of velocities. Peaks in the resulting velocity spectra identify linear events in the GPR data gathers like DGW events and allow for estimating the corresponding velocities. In addition to obtaining a DGW velocity measurement, we propose a robust method to estimate the associated velocity uncertainties based on the width of the peak in the calculated velocity spectrum. Our proposed method is tested on synthetic data examples to evaluate the influence of subsurface velocity, surveying geometry and signal frequency on the accuracy of estimated ground‐wave velocities. In addition, we investigate the influence of such velocity uncertainties on subsequent soil water content estimates using an established petrophysical relationship. Furthermore, we apply our approach to analyse field data, which were collected across a test site in Canada to monitor a wide range of seasonal soil moisture variations. A comparison between our spectral velocity estimates and results derived from manually picked ground‐wave arrivals shows good agreement, which illustrates that our spectral velocity analysis is a feasible tool to analyse DGW arrivals in multi‐offset GPR data gathers in an objective and more automated manner.

Loading

Article metrics loading...

/content/journals/10.3997/1873-0604.2012038
2012-09-01
2024-04-20
Loading full text...

Full text loading...

References

  1. AllredB.J., DanielsJ.J. and Reza EhsaniM.2008. Handbook of Agricultural Geophysics. CRC Press.
    [Google Scholar]
  2. AnnanA.P.2005. Ground‐penetrating radar.Near Surface Geophysics (ed. D.K.Butler ), 357–438. SEG.
    [Google Scholar]
  3. ArconeS.A., PeapplesP. and LiuL.2003. Propagation of a ground‐penetrating radar (GPR) pulse in a thin‐surface waveguide.Geophysics68, 1922–1933.
    [Google Scholar]
  4. BinleyA., WinshipP., MiddletonR., PokarM. and WestJ.2001. High‐resolution characterization of vadose zone dynamics using cross‐borehole radar.Water Resources Research37, 2639–2652.
    [Google Scholar]
  5. BoothA.D., ClarkR.A., HamiltonK. and MurrayT.2010. Multi‐offset ground penetrating radar methods to image buried foundations of a medieval town wall, Great Yarmouth, UK.Archaeological Prospection17, 103–116.
    [Google Scholar]
  6. BoothA.D., ClarkR.A. and MurrayT.2011. Influences on the resolution of GPR velocity analyses and a Monte Carlo simulation for establishing velocity precision.Near Surface Geophysics9, 399‐411.
    [Google Scholar]
  7. BrostenT.R., BradfordJ.H., McNamaraJ.P., GooseffM.N., ZarnetskeJ.P., BowdenW.B. and JohnstonE.J.2009. Multi‐offset GPR methods for hyporheic zone investigations.Near Surface Geophysics7, 247–257.
    [Google Scholar]
  8. CassianiG., StrobbiaC. and GallottiL.2004. Vertical radar profiles for the characterization of deep vadose zones.Vadose Zone Journal3, 1093–1105.
    [Google Scholar]
  9. GalagedaraL.W., ParkinG.W., RedmanJ.D., von BerktoldP. and EndresA.L.2005a. Field studies of the GPR ground wave method for estimating soil water content during irrigation and drainage.Journal of Hydrology301, 182–197.
    [Google Scholar]
  10. GalagedaraL.W., RedmanJ.D., ParkinG.W., AnnanA.P. and EndresA.L.2005b. Numerical modeling of GPR to determine the direct ground wave sampling depth.Vadose Zone Journal4, 1096–1106.
    [Google Scholar]
  11. GreavesR.J., LesmesD.P., LeeJ.M. and ToksözJ.M.1996. Velocity variations and water content estimated from multioffset, ground penetrating radar.Geophysics61, 683–695.
    [Google Scholar]
  12. GroteK., CristT. and NickelC.2010. Experimental estimation of the GPR ground wave sampling depth.Water Resources Resources46, W10520.
    [Google Scholar]
  13. HeimovaaraT.J., BoutenW. and VerstratenJ.M.1994. Frequency domain analysis of time‐domain reflectometry waveforms: 2. A four component complex dielectric mixing model for soils.Water Resources Research30, 201–209.
    [Google Scholar]
  14. HillelD.1997. Environmental Soil Physics. Academic Press, New York.
    [Google Scholar]
  15. HuismanJ.A., HubbardS.S., RedmanJ.D. and AnnanA.P.2003a. Measuring soil water content with ground penetrating radar: A review.Vadose Zone Journal2, 476–491.
    [Google Scholar]
  16. HuismanJ.A., SnepvangersJ.J.J.C., BoutenW. and HeuvelinkG.B.M.2003b. Monitoring temporal development of spatial soil water content variation: Comparison of ground penetrating radar and time domain reflectometry.Vadose Zone Journal2, 519–529.
    [Google Scholar]
  17. HuismanJ.A., SperlJ., BoutenW. and BerstratenJ.M.2001. Soil water content measurements at different scales: Accuracy of time domain reflectometry and ground penetrating radar.Journal of Hydrology245, 48–58.
    [Google Scholar]
  18. van der KrukJ., SteelmanC.M., EndresA.L. and VereeckenH.2009. Dispersion inversion of electromagnetic pulse propagation within freezing and thawing soil waveguides.Geophysical Research Letters36, L18503.
    [Google Scholar]
  19. van der KrukJ., StreichR. and GreenA.2006. Properties of surface waveguides derived from separate and joint inversion of dispersive TE and TM GPR data.Geophysics71, K19–K29.
    [Google Scholar]
  20. LambotS., SlobE.C., van den BoschI., StockbroeckxB., ScheersB. and VancloosterM.2004. Estimating soil electric properties from mono‐static ground‐penetrating radar signal inversion in the frequency domain.Water Resources Research40, W04205.
    [Google Scholar]
  21. RedmanJ.D.2008. Soil Water Content Measurement Using the Ground‐Penetrating Radar Surface Reflectivity Method.Handbook of Agricultural Geophysics, 317–322, CRC Press.
    [Google Scholar]
  22. SheriffR.E. and GeldartL.P.1999. Exploration Seismology. 2nd edition. Cambridge University Press.
    [Google Scholar]
  23. SteelmanC.M. and EndresA.L.2009. Evolution of high‐frequency ground‐penetrating radar direct ground wave propagation during thin frozen soil layer development.Cold Regions Science and Technology57, 116–122.
    [Google Scholar]
  24. SteelmanC.M. and EndresA.L.2010. An Examination of direct ground wave soil moisture monitoring over an annual cycle of soil conditions.Water Resources Research46, W11533.
    [Google Scholar]
  25. SteelmanC.M. and EndresA.L.2011. Comparison of petrophysical relationships for soil moisture estimation using GPR ground waves.Vadose Zone Journal10, 270–285.
    [Google Scholar]
  26. SteelmanC.M., EndresA.L. and van der KrukJ.2010. Field observation of shallow freeze and thaw processes using high‐frequency ground‐penetrating radar.Hydrological Processes24, 2022‐2033.
    [Google Scholar]
  27. ToppG.C., DavisJ.L. and AnnanA.P.1980. Electromagnetic determination of soil water content: Measurements in coaxial transmission lines.Water Resources Research16(3), 574–582.
    [Google Scholar]
  28. TronickeJ., DietrichP., WahligU. and AppelE.2002. Integrating GPR and crosshole radar tomography: A validation experiment in braided stream deposits.Geophysics67, 1495–1504.
    [Google Scholar]
  29. TronickeJ. and KnollM.D.2005. Vertical radar profiling: Influence of survey geometry on first arrival traveltimes and amplitudes.Journal of Applied Geophysics57, 179–191.
    [Google Scholar]
  30. TuressonA.2007. Comparative analysis of the multi‐offset ground‐penetrating radar and shear wave reflection methods.Journal of Environmental & Engineering Geophysics12(2) 163–171.
    [Google Scholar]
  31. VereeckenH., BinleyA., TitovK., RevilK. and CassianiG.2006. Applied Hydrogeophysics. Kluwer Academic Publications.
    [Google Scholar]
  32. YiM.‐J. and EndresA.L.2006. Application of f‐k analysis to multi‐offset GPR direct wave measurements for water content: A modeling study.Proceedings of the 11th International Conference on Ground Penetrating Radar, paper hyd.2.
    [Google Scholar]
  33. YilmazÖ.1999. Seismic data processing.Society of Exploration Geophysics169.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.3997/1873-0604.2012038
Loading
/content/journals/10.3997/1873-0604.2012038
Loading

Data & Media loading...

  • Article Type: Research Article

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error