Nonlinear trends and multiyear cycles in sea level records

Abstract

[1] We analyze the Permanent Service for Mean Sea Level (PSMSL) database of sea level time series using a method based on Monte Carlo Singular Spectrum Analysis (MC-SSA). We remove 2-30 year quasi-periodic oscillations and determine the nonlinear long-term trends for 12 large ocean regions. Our global sea level trend estimate of 2.4 ± 1.0 mm/yr for the period from 1993 to 2000 is comparable with the 2.6 ± 0.7 mm/yr sea level rise calculated from TOPEX/Poseidon altimeter measurements. However, we show that over the last 100 years the rate of 2.5 ± 1.0 mm/yr occurred between 1920 and 1945, is likely to be as large as the 1990s, and resulted in a mean sea level rise of 48 mm. We evaluate errors in sea level using two independent approaches, the robust bi-weight mean and variance, and a novel ''virtual station'' approach that utilizes geographic locations of stations. Results suggest that a region cannot be adequately represented by a simple mean curve with standard error, assuming all stations are independent, as multiyear cycles within regions are very significant. Additionally, much of the between-region mismatch errors are due to multiyear cycles in the global sea level that limit the ability of simple means to capture sea level accurately. We demonstrate that variability in sea level records over periods 2-30 years has increased during the past 50 years in most ocean basins.

Sea-Level Rise from the Late 19th to the Early 21st Century

“…6). They all agree approximately with our updated GMSL time series and the longer of these estimates (Jevrejeva et al 2006) also has an acceleration in the 1930s and a pause in the rise commencing in the 1960s. These changes are also present in a number of individual sea-level records ).…”

“…It is then necessary to average the rates of rise over some time step and integrate the results to get the sea-level change. Holgate and Woodworth (2004) used this approach and Jevrejeva et al (2006) used a virtual station method of averaging neighbouring station sea-level changes in several regions and then averaging to get the global mean sea-level change. No attempt was made to interpolate between the locations of observations and thus to estimate deep ocean sea level.…”

Sea-Level Rise from the Late 19th to the Early 21st Century

“…There are other recent estimates of changes in GMSL for this period widely available (Jevrejeva et al 2006;Holgate and Woodworth, 2004;Fig. 6).…”

Evidence for Century-Timescale Acceleration in Mean Sea Levels and for Recent Changes in Extreme Sea Levels

“…They obtained a global-average acceleration of sea level between 1880 and 2009 of 0.009 ± 0.003 mm/year 2 (quadratic coefficient 'c' = 0.0045 ± 0.0015 mm/year 2 ). Jevrejeva et al (2006) derived time series of regional and global sea level by combining both short and long tide gauge records from the early part of the 19 th century onwards with the use of a 'virtual station' technique, and demonstrated changes in global sea level trend between the 19 th and 20 th centuries similar to those of Church and White (see comparisons of these analyses in Woodworth et al 2009a). Jevrejeva et al (2008) attempted to extend the reconstruction analysis over three centuries with the use of the small number of long records, concluding that the long-term acceleration could have started nearer to the beginning of the 19 th century rather than at its end, as preferred by other studies.…”