Advertisement

Marine Geophysical Researches

, Volume 31, Issue 3, pp 223–238 | Cite as

Evolution of errors in the altimetric bathymetry model used by Google Earth and GEBCO

  • K. M. MarksEmail author
  • W. H. F. Smith
  • D. T. Sandwell
Original Research Paper

Abstract

We analyze errors in the global bathymetry models of Smith and Sandwell that combine satellite altimetry with acoustic soundings and shorelines to estimate depths. Versions of these models have been incorporated into Google Earth and the General Bathymetric Chart of the Oceans (GEBCO). We use Japan Agency for Marine-Earth Science and Technology (JAMSTEC) multibeam surveys not previously incorporated into the models as “ground truth” to compare against model versions 7.2 through 12.1, defining vertical differences as “errors.” Overall error statistics improve over time: 50th percentile errors declined from 57 to 55 to 49 m, and 90th percentile errors declined from 257 to 235 to 219 m, in versions 8.2, 11.1 and 12.1. This improvement is partly due to an increasing number of soundings incorporated into successive models, and partly to improvements in the satellite gravity model. Inspection of specific sites reveals that changes in the algorithms used to interpolate across survey gaps with altimetry have affected some errors. Versions 9.1 through 11.1 show a bias in the scaling from gravity in milliGals to topography in meters that affected the 15–160 km wavelength band. Regionally averaged (>160 km wavelength) depths have accumulated error over successive versions 9 through 11. These problems have been mitigated in version 12.1, which shows no systematic variation of errors with depth. Even so, version 12.1 is in some respects not as good as version 8.2, which employed a different algorithm.

Keywords

Errors Satellite bathymetry Bathymetric grids Google Earth GEBCO Multibeam 

Notes

Acknowledgments

Data and web applications discussed in this paper are available at the following websites: Smith and Sandwell’s (1997) altimetric bathymetry grid V12.1 (http://topex.ucsd.edu/WWW_html/mar_topo.html), SRTM30_Plus V6.0 (http://topex.ucsd.edu/WWW_html/srtm30_plus.html), GEBCO_08 bathymetry grid version 20091120 (http://www.gebco.net), Google Earth (http://earth.google.com), and JAMSTEC multibeam data (http://www.godac.jamstec.go.jp/cruisedata/e/). Data used in this study were acquired during the KR05-01 cruise of R/V KAIREI and the MR06-01 cruise of R/V MIRAI, Japan Agency for Marine-Earth Science and Technology. We thank JAMSTEC for making multibeam echo sounder data freely available. The comments of two anonymous reviewers improved this manuscript. The views, opinions, and findings contained in this report are those of the authors and should not be construed as an official National Oceanic and Atmospheric Administration or U.S. Government position, policy, or decision.

References

  1. Baudry N, Calmant S (1991) 3-D modelling of seamount topography from satellite altimetry. Geophys Res Lett 18:1143–1146. doi: 10.1029/91GL01341 CrossRefGoogle Scholar
  2. Becker JJ, Sandwell DT, Smith WHF, Braud J, Binder B, Depner J, Fabre D, Factor J, Ingalls S, Kim S-H, Ladner R, Marks K, Nelson S, Pharaoh A, Trimmer R, Von Rosenburg J, Wallace G, Weatherall P (2009) Global bathymetry and elevation data at 30 arc seconds resolution: SRTM30_PLUS. Mar Geod 32:355–371. doi 10.1080/01490410903297766 CrossRefGoogle Scholar
  3. Bendat JS, Piersol AG (1986) Random data: analysis and measurement procedures, 2nd edn. Wiley, New YorkGoogle Scholar
  4. British Oceanographic Data Center (2003) Centenary edition of the GEBCO digital atlas [CD-ROM]. Published on behalf of the Intergovernmental Oceanographic Commission and the International Hydrographic Organization, LiverpoolGoogle Scholar
  5. Calmant S (1994) Seamount topography by least-squares inversion of altimetric geoid heights and shipborne profiles of bathymetry and/or gravity. Geophys J Int 119:428–452. doi: 10.1111/j.1365-246X.1994.tb00133.x CrossRefGoogle Scholar
  6. Goff JA, Smith WHF (2003) A correspondence of altimetric gravity texture to abyssal hill morphology along the flanks of the Southeast Indian ridge. Geophys Res Lett 30:24. doi: 10.1029/2003GL018913 CrossRefGoogle Scholar
  7. Goff JA, Smith WHF, Marks KM (2004) The contributions of abyssal hill morphology and noise to altimetry gravity fabric. Oceanography 17:24–37Google Scholar
  8. Jakobsson M, Macnab R, Mayer L, Anderson R, Edwards M, Hatzky J, Schenke H-W, Johnson P (2008) An improved bathymetric portrayal of the Arctic Ocean: implications for ocean modeling and geological, geophysical and oceanographic analysis. Geophys Res Lett 35:L07602. doi: 10.1029/2008GL033520 CrossRefGoogle Scholar
  9. Jung W-Y, Vogt PR (1992) Predicting bathymetry from Geosat-ERM and shipborne profiles in the South Atlantic Ocean. Tectonophysics 210:235–253. doi: 10.1016/0040-1951(92)90324-Y CrossRefGoogle Scholar
  10. Marks KM, Smith WHF (2006) An evaluation of publicly available global bathymetry grids. Mar Geophys Res 27:19–34. doi: 10.1007/s11001-005-2095-4 CrossRefGoogle Scholar
  11. Marks KM, Smith WHF (2007) Some remarks on resolving seamounts in satellite gravity. Geophys Res Lett 34:L03307. doi: 10.1029/2006GL028857 CrossRefGoogle Scholar
  12. Marks KM, Smith WHF (2009) An uncertainty model for deep ocean single beam and multibeam echo sounder data. Mar Geophys Res 29:239–250. doi: 10.1007/s11001-008-9060-y Google Scholar
  13. Oldenburg DW (1974) The inversion and interpretation of gravity anomalies. Geophysics 39:526–536. doi: 10.1190/1.1440444 CrossRefGoogle Scholar
  14. Parker RL (1973) The rapid calculation of potential anomalies. Geophys J Roy Astron Soc 31:447–455. doi:  10.1111/j.1365-246X.1973.tb06513.x Google Scholar
  15. Ramillien G, Cazenave A (1997) Global bathymetry derived from altimeter data of the ERS-1 Geodetic Mission. J Geodyn 23:129–149. doi: 10.1016/S0264-3707(96)00026-9 CrossRefGoogle Scholar
  16. Sandwell DT, Smith WHF (1997) Marine gravity anomaly from Geosat and ERS 1 satellite altimetry. J Geophys Res 102:10039–10054. doi:  10.1029/96JB03223 CrossRefGoogle Scholar
  17. Sandwell DT, Smith WHF (2005) Retracking ERS-1 altimeter waveforms for optimal gravity field recovery. Geophys J Int 163:79–89. doi: 10.1111/j.1365-246X.2005.02724.x CrossRefGoogle Scholar
  18. Sandwell DT, Smith WHF (2009) Global marine gravity from retracked Geosat and ERS-1 altimetry: ridge segmentation versus spreading rate. J Geophys Res 114:B01411. doi: 10.1029/2008JB006008 CrossRefGoogle Scholar
  19. Sichoix L, Bonneville A (1996) Prediction of bathymetry in French Polynesia constrained by shipboard data. Geophys Res Lett 23:2469–2472. doi: 10.1029/96GL02122 CrossRefGoogle Scholar
  20. Smith WHF (1993) On the accuracy of digital bathymetric data. J Gephys Res 98(B6):9591–9603. doi: 10.1029/93JB00716 CrossRefGoogle Scholar
  21. Smith WHF, Sandwell DT (1994) Bathymetric prediction from dense satellite altimetry and sparse shipboard bathymetry. J Geophys Res 99(B11):21803–21824. doi: 10.1029/94JB00988 CrossRefGoogle Scholar
  22. Smith WHF, Sandwell DT (1997) Global sea floor topography from satellite altimetry and ship depth soundings. Science 277:1956–1962. doi: 10.1126/science.277.5334.1956 CrossRefGoogle Scholar
  23. Wessel P, Smith WHF (1998) New, improved version of generic mapping tools released. EOS Trans AGU 79:579. doi: 10.1029/98EO00426 CrossRefGoogle Scholar
  24. Wessel P, Watts A (1988) On the accuracy of gravity measurements. J Geophys Res 93(B1):393–413. doi: 10.1029/JB093iB01p00393 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. (outside the USA) 2010

Authors and Affiliations

  • K. M. Marks
    • 1
    Email author
  • W. H. F. Smith
    • 1
  • D. T. Sandwell
    • 2
  1. 1.NOAA Laboratory for Satellite AltimetrySilver SpringUSA
  2. 2.Scripps Institution of OceanographyLa JollaUSA

Personalised recommendations