Skip to main content

Advertisement

We’d like to understand how you use our websites in order to improve them. Register your interest.

Treatment of horizontal and vertical tidal signals in GPS data: A case study on a floating ice shelf

Abstract

Knowledge of the surface velocity and strain of ice shelves is important in determining their present kinematic state and detecting any change in that state. Data collected using the Global Positioning System (GPS) often plays an important role in determing these parameters, either directly, or as ground-truthing to other techniques such as InSAR. The processing of GPS data on floating ice shelves is complicated by the presence of a distinct vertical tidal signal and large horizontal motions in the data. Over a one hour period, vertical and horizontal movements can be as much as 0.3 metres and 0.1 metres respectively. For such GPS data to be processed using conventional static methods would require the observation period to be split into small (1 hour) segments, and the segments processed separately. Other processing options may include kinematic processing or sequential processing, although these techniques have their own drawbacks. Instead, we have developed software to remove signals based on a priori knowledge of the ice shelf motion. The tidal signal is removed using a local tide model and the horizontal velocity effect is corrected to a specific time epoch. This allows us to process our GPS data in a tide-free, velocity-free environment for a given day using conventional GPS processing software. The corrected GPS data, now largely free from the effects of ice shelf motion, may then be combined to produce high precision velocity and strain rate models of the ice shelf.

References

  1. Bondesan, A., A. Capra, A. Gubellini, and J. Tison, On the use of static GPS measurements to record the tidal response of a small Antarctic ice shelf (Hells Gate Ice Shelf, Victoria Land), Geografia Fisica Dinamica Quaternaria, 17, 123–129, 1994.

    Google Scholar 

  2. Doake, C. S. M., Gravimetric tidal measurements on Filchner Ronne Ice Shelf, in 7th International Workshop of the Filchner-Ronne Ice Shelf Programme, edited by H. Oerter, pp. 34–39, Alfred-Wegener-Institute for Polar and Marine Research, SchloB Senden, Germany, 1992.

    Google Scholar 

  3. Hughes, T., On the pulling power of ice streams, Journal of Glaciology, 38(128), 125–151, 1992.

    Google Scholar 

  4. King, R. W. and Y. Bock, Documentation for the GAMIT GPS analysis software (version 9.8), Unpublished, Massachusetts Institute of Technology, 1999.

  5. King, M., L. Nguyen, R. Coleman, and P. Morgan, Strategies for high precision processing of GPS measurements with application to the Amery Ice Shelf, East Antarctica, GPS Solutions, 4(1), 2–12, 2000.

    Article  Google Scholar 

  6. MacAyeal, D. R., Numerical simulations of the Ross Sea tides, J. Geophys. Res., 89(C1), 607–615, 1984.

    Article  Google Scholar 

  7. Mader, G. L. and J. R. Mackay, Calibration of GPS antennas, in 1996 Analysis Center Workshop, edited by R. E. Neilan, P. A. Van Scoy, and J. F. Zumberge, pp. 81–105, IGS Central Bureau, Silver Spring, Maryland, 1996.

    Google Scholar 

  8. Pedley, M., J. G. Paren, and J. R. Potter, The tidal spectrum underneath Antarctic ice shelves, J. Geophys. Res., 91(C11), 13001–13009, 1986.

    Article  Google Scholar 

  9. Rignot, E., L. Padman, D. R. MacAyeal, and M. Schmeltz, Observation of ocean tides below the Filchner and Ronne Ice Shelves, Antarctica, using synthetic aperture radar: comparison with tide model predictions, J. Geophys. Res., 105(C8), 19615–19630, 2000.

    Article  Google Scholar 

  10. Robertson, R. A., L. Padman, and G. D. Egbert, Ocean, Ice and Atmosphere, Interactions at the Antarctic Continental Margin, Vol. 75, edited by S. S. Jacobs and R. F. Weiss, pp. 341–369, AGU, Washington, 1998.

  11. Stephenson, S. N., C. S. M. Doake, and J. A. C. Horsfall, Tidal flexure of ice shelves measured by tiltmeter, Nature, 282, 496–497, 1979.

    Article  Google Scholar 

  12. Vaughan, D., Tidal flexure at ice shelf margins, J. Geophys. Res., 100(B4), 6213–6224, 1995.

    Article  Google Scholar 

  13. Wong, A. P. S., N. L. Bindoff, and A. Forbes, Ocean, Ice and Atmosphere, Interactions at the Antarctic Continental Margin, Vol. 75, edited by S. S. Jacobs and R. F. Weiss, pp. 173–187, AGU, Washington, 1998.

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Matt King.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

King, M., Coleman, R. & Morgan, P. Treatment of horizontal and vertical tidal signals in GPS data: A case study on a floating ice shelf. Earth Planet Sp 52, 1043–1047 (2000). https://doi.org/10.1186/BF03352328

Download citation

Keywords

  • Tide Model
  • Electronic Distance Measurement
  • Beaver Lake
  • Static Reference System