Time and tide: analysis of sea level time series
A number of recent papers have examined sea level data, both local tide gauge records and regional/global averages, to estimate not only how fast sea level is rising but how the rate has changed over time, i.e. its pattern of acceleration and deceleration. In addition, a number of claims of cyclic/quasi-periodic variations have been proposed. However, many of these papers contain technical problems which call their results into question. In particular, the issue of autocorrelation is often ignored, and even when it is addressed its impact has sometimes been misinterpreted. Autocorrelation does more than just affect the standard errors of regression analysis, it can also make the spectrum of a noise process distinctly “red” and therefore be highly suggestive of low-frequency periodic or pseudo-periodic behavior when none is present. If any analysis is applied which acts as a band-pass filter, it can further exaggerate the illusion of oscillatory behavior. These issues are highlighted in a small number of recent papers, in order to improve the quality of future work on this subject.
KeywordsTime series Sea level Climate oscillations
We would like to acknowledge Dr. Alexander Glass for initiating the discussion that lead to this manuscript.
- Bindoff NL, Willebrand J, Artale V, Cazenave A, Gregory JM, Gulev S, Hanawa K, Le Quere C, Levitus S, Nojiri Y, Shum CK, Talley LD, Unnikrishnan AS (2007) Observations: oceanic climate change and sea level, climate change 2007: the physical science basis. In: Solomon D, Qin D, Manning M, Marquis M, Averyt KB, Tignor M, Miller HL, Chen Z (eds) Contribution of working group 1 to the fourth assessment report of the intergovernmental panel on climate change, Cambridge University Press, Cambridge, UK and NY, USAGoogle Scholar
- Boon JD (2012) Evidence of sea level acceleration at U.S. and Canadian Tide Stations, Atlantic Coast, North America. J Coast Res 28(6):1437–1445. doi: 10.2112/JCOASTRES-D-12-00102.1
- Boretti A (2012) Is there any support in the long term tide gauge data to the claims that parts of Sydney will be swamped by rising sea levels? Coast Eng 64:161–167. doi: 10.1016/j.coastaleng.2012.01.006
- Boretti A, Watson T (2012) The inconvenient truth: ocean level not rising in Australia. Energy Environ 23(5):801–818Google Scholar
- Burton DA (2012) Comments on Assessing future risk: quantifying the effects of sea level rise on storm surge risk for the southern shores of Long Island, New York, by Christine C. Shepard, Vera N. Agostini, Ben Gilmer, Tashya Allen, Jeff Stone, William Brooks and Michael W. Beck. Nat Hazards 63(2):1219–1221CrossRefGoogle Scholar
- Church JA, Clark PU, Cazenave A, Gregory JM, Jevrejeva S, Levermann A, Merrifield MA, Milne GA, Nerem RS, Nunn PD, Payne AJ, Pfeffer WT, Stammer D, Unnikrishnan AS (2013) Sea level change. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK and NewYork, USAGoogle Scholar
- Dean RG, Houston JR (2013) Recent sea level trends and accelerations: comparison of tide gauge and satellite results. Coast Eng 75:4–9. doi: 10.1016/j.coastaleng.2013.01.001
- Hunter JR, Brown MJI (2013) Discussion of Boretti, A., ‘Is there any support in the long term tide gauge data to the claims that parts of Sydney will be swamped by rising sea levels?’, Coast Eng 64:161–167, June 2012. Coast Eng 75:1–3. doi: 10.1016/j.coastaleng.2012.12.003
- IPCC (2013) Climate change 2013: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, CambridgeGoogle Scholar
- PSMSL (2013) Permanent service for mean sea level, data. http://www.psmsl.org/data/obtaining/
- Scafetta N (2013) Multi-scale dynamical analysis (MSDA) of sea level records versus PDO, AMO, and NAO indexes. Clim Dyn. doi: 10.1007/s00382-013-1771-3
- Woodworth PL, Player R (2003) The permanent service for mean sea level: an update to the 21st century. J Coast Res 19:287–295Google Scholar