HR: 17:45h
AN: G44A-08    [Abstracts]
TI: Nonlinear trends and multi-year cycles in regional and global sea level records
AU: * Moore, J C
EM: jmoore@ulapland.fi
AF: Arctic Centre, University of Lapland, Box 122, Rovaniemi, 96101, Finland
AU: * Moore, J C
EM: jmoore@ulapland.fi
AF: Division of Geophysics, University of Oulu, Fysikaalisten tieteiden laitos PL 3000, Oulun yliopisto, 90014, Finland
AU: Grinsted, A
EM: ag@glaciology.net
AF: Arctic Centre, University of Lapland, Box 122, Rovaniemi, 96101, Finland
AU: Jevrejeva, S
EM: sveta@pol.ac.uk
AF: Joseph Proudman building 6 Brownlow Street Proudman Oceanographic Laboratory, Joseph Proudman building 6 Brownlow Street, Liverpool, L3 5DA, United Kingdom
AU: Holgate, S
EM: simonh@pol.ac.uk
AF: Joseph Proudman building 6 Brownlow Street Proudman Oceanographic Laboratory, Joseph Proudman building 6 Brownlow Street, Liverpool, L3 5DA, United Kingdom
AB: 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 multi-year cycles within regions are very significant. Additionally, much of the between-region mismatch errors are due to multi-year 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.
DE: 1222 Ocean monitoring with geodetic techniques (1225, 1641, 3010, 4532, 4556, 4560, 6959)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
SC: Geodesy [G]
MN: 2007 Fall Meeting