Letter

Unabated global mean sea-level rise over the satellite altimeter era

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Abstract

The rate of global mean sea-level (GMSL) rise has been suggested to be lower for the past decade compared with the preceding decade as a result of natural variability1, with an average rate of rise since 1993 of +3.2 ± 0.4 mm yr−1 (refs 2, 3). However, satellite-based GMSL estimates do not include an allowance for potential instrumental drifts (bias drift4,5). Here, we report improved bias drift estimates for individual altimeter missions from a refined estimation approach that incorporates new Global Positioning System (GPS) estimates of vertical land movement (VLM). In contrast to previous results (for example, refs 6, 7), we identify significant non-zero systematic drifts that are satellite-specific, most notably affecting the first 6 years of the GMSL record. Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied. These rates are in closer agreement with the rate derived from the sum of the observed contributions2, GMSL estimated from a comprehensive network of tide gauges with GPS-based VLM applied (updated from ref. 8) and reprocessed ERS-2/Envisat altimetry9. Second, in contrast to the previously reported slowing in the rate during the past two decades1, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections2,10, and larger than the twentieth-century acceleration2,8,10.

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References

  1. 1.

    et al. The rate of sea-level rise. Nature Clim. Change 4, 358–361 (2014).

  2. 2.

    et al. in Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) Ch. 13 (IPCC, Cambridge Univ. Press, 2013)

  3. 3.

    et al. Comparison of global mean sea level time series from TOPEX/Poseidon, Jason-1, and Jason-2. Mar. Geod. 35, 20–41 (2012).

  4. 4.

    & The challenges in long-term altimetry calibration for addressing the problem of global sea level change. Adv. Space Res. 51, 1284–1300 (2013).

  5. 5.

    An improved calibration of satellite altimetric heights using tide gauge sea levels with adjustment for land motion. Mar. Geod. 23, 145–166 (2000).

  6. 6.

    , , & A new assessment of the error budget of global Mean Sea Level rate estimated by satellite altimetry over 1993–2008. Ocean Sci. 5, 193–201 (2009).

  7. 7.

    , , & in Understanding Sea-Level Rise and Variability (eds Church, J. A., Woodworth, P. L., Aarup, T. & Stanley Wilson, W.) 122–142 Ch. 5, (Wiley–Blackwell, 2009).

  8. 8.

    & Sea-level rise from the late 19th to the early 21st century. Surv. Geophys. 32, 585–602 (2011).

  9. 9.

    et al. Influence of time variable geopotential models on precise orbits of altimetry satellites, global and regional mean sea level trends. Adv. Space Res. 54, 92–118 (2014).

  10. 10.

    et al. Sea-level rise by 2100. Science 342, 1445–1445 (2013).

  11. 11.

    & Sea-level rise and its impact on coastal zones. Science 328, 1517–1520 (2010).

  12. 12.

    et al. TOPEX/POSEIDON mission overview. J. Geophys. Res. 99, 24369–324381 (1994).

  13. 13.

    et al. The Jason-1 mission. Mar. Geod. 26, 131–146 (2003).

  14. 14.

    et al. The OSTM/Jason-2 mission. Mar. Geod. 33, 4–25 (2010).

  15. 15.

    Monitoring the stability of satellite altimeters with tide gauges. J. Atmos. Ocean. Technol. 15, 721–730 (1998).

  16. 16.

    et al. Improved determination of global mean sea level variations using TOPEX/POSEIDON altimeter data. Geophys. Res. Lett. 24, 1331–1334 (1997).

  17. 17.

    , , & Evaluating and Interpreting the Global and Regional Sea Level Climate Record. Ocean Surface Topography Science Team Meeting (Oral Presentation, 2010);

  18. 18.

    et al. Regional biases in absolute sea-level estimates from tide gauge data due to residual unmodeled vertical land movement. Geophys. Res. Lett. 39, L14604 (2012).

  19. 19.

    Global glacial isostasy and the surface of the ice-age Earth: The ICE-5G (VM2) model and GRACE. Annu. Rev. Earth Planet. Sci. 32, 111–149 (2004).

  20. 20.

    , , & Sea-level fingerprint of continental water and ice mass change from GRACE. Geophys. Res. Lett. 37, L19605 (2010).

  21. 21.

    , & ITRF2008: An improved solution of the international terrestrial reference frame. J. Geod. 85, 457–473 (2011).

  22. 22.

    , , , & A reassessment of global and regional mean sea level trends from TOPEX and Jason-1 altimetry based on revised reference frame and orbits. Geophys. Res. Lett. 34, L14608 (2007).

  23. 23.

    , , & Probabilistic reanalysis of twentieth-century sea-level rise. Nature 517, 481–484 (2015).

  24. 24.

    et al. A reconciled estimate of ice-sheet mass balance. Science 338, 1183–1189 (2012).

  25. 25.

    et al. Mitigating the effects of vertical land motion in tide gauge records using a state-of-the-art GPS velocity field. Glob. Planet. Change 98–99, 6–17 (2012).

  26. 26.

    & Proceedings of the TOPEX/Poseidon/Jason-1 Science Working Team Meeting (2012).

  27. 27.

    AVISO and PODAAC user handbook—IGDR and GDR Jason Products 2nd edn (AVISO, 2003)

  28. 28.

    CNES OSTM/Jason-2 Products Handbook. Report No. SALP-MU-M-OP-15815-CN (CNES, 2009)

  29. 29.

    Characterization and correction of a drift in calibration of the TOPEX microwave radiometer. IEEE Trans. Geosci. Remote Sensing 40, 509–511 (2002).

  30. 30.

    PO.DAAC Merged GDR (TOPEX/Poseidon) Generation B User’s Handbook Version 2 (JPL, 1997)

  31. 31.

    A novel near-land radiometer wet path-delay retrieval algorithm: Application to the Jason-2/OSTM Advanced Microwave Radiometer. IEEE Trans. Geosci. Remote Sensing 48, 1986–1992 (2010).

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Acknowledgements

This work was supported by the Integrated Marine Observing System (IMOS)—IMOS is a national collaborative research infrastructure, supported by the Australian Government. Additional support was provided by the Australian Government Department of the Environment, the Bureau of Meteorology and CSIRO through the Australian Climate Change Science Programme. Part of this project was supported through an Australian Research Councils Discovery Project (DP0877381), and a Future Fellowship (FT110100207). Altimetry products were obtained from the Jet Propulsion Laboratory PO.DAAC and Centre National d’Études Spatiales AVISO archives, with additional dry path delay corrections obtained from the Radar Altimeter Database System (http://rads.tudelft.nl/rads/). We thank B. Haines (JPL) and F. Lemoine (GSFC) for their altimeter orbit solutions, S. Nerem and D. Masters for providing the University of Colorado along-track data, R. Riva for rates of elastic deformation, and J. Hunter for useful comments on the manuscript. TG data were provided by the University of Hawaii Sea Level Center, and the Australian National Tidal Centre (NTC). The authors thank suppliers of GPS data (such as IGS, TIGA, BIGF, SOPAC) and NASA/JPL for making the GIPSY software and GPS orbit and clock products available.

Author information

Affiliations

  1. Discipline of Geography and Spatial Sciences, School of Land and Food, University of Tasmania, Hobart, Tasmania 7001, Australia

    • Christopher S. Watson
    •  & Matt A. King
  2. Centre for Australian Weather and Climate Research, A partnership between CSIRO and the Australian Bureau of Meteorology, CSIRO Oceans and Atmosphere Flagship, Hobart, Tasmania 7001, Australia

    • Neil J. White
    • , John A. Church
    •  & Benoit Legresy
  3. School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK

    • Matt A. King
  4. Department of Geological Sciences, New Mexico State University, Las Cruces, New Mexico 88003, USA

    • Reed J. Burgette

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Contributions

C.S.W. undertook the bias drift analysis and led the drafting of the manuscript. N.J.W. processed the altimeter data and worked closely on the methods development and analysis with C.S.W. and J.A.C. B.L. assisted with the generation of the altimeter data. M.A.K. undertook the VLM analysis and R.J.B. provided the earthquake threshold analysis. All authors contributed significantly to the drafting and revision of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Christopher S. Watson.

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