Climate of the Past www.clim-past.net 1814-9324 1814-9332 5 2 2009 10.5194/cp-5-217-2009 http://www.clim-past.net/5/217/2009/ http://www.clim-past.net/5/217/2009/cp-5-217-2009.html http://www.clim-past.net/5/217/2009/cp-5-217-2009.pdf 217 227 2009-06-23 Two-dimensional reconstruction of past sea level (1950–2003) from tide gauge data and an Ocean General Circulation Model W. Llovel william.llovel@legos.obs-mip.fr A. Cazenave P. Rogel A. Lombard M. B. Nguyen LEGOS, OMP, 18 avenue Edouard Belin, 31401 Toulouse Cedex 09, France CERFACS/URA1875, 42, Avenue Gaspard Coriolis, 31057 Toulouse Cedex 01, France CNES, 18 avenue Edouard Belin, 31401 Toulouse Cedex 09, France A two-dimensional reconstruction of past sea level is proposed at yearly interval over the period 1950–2003 using tide gauge records from 99 selected sites and 44-year long (1960–2003) 2°×2° sea level grids from the OPA/NEMO ocean general circulation model with data assimilation. We focus on the regional variability and do not attempt to compute the global mean trend. An Empirical Orthogonal Function decomposition of the reconstructed sea level grids over 1950–2003 displays leading modes that reflect two main components: (1) a long-term (multi-decadal), regionally variable signal and (2) an interannual, regionally variable signal dominated by the signature of El Nino-Southern Oscillation. Tests show that spatial trend patterns of the 54-year long reconstructed sea level significantly depend on the temporal length of the two-dimensional sea level signal used for the reconstruction (i.e., the length of the gridded OPA/NEMO sea level time series). On the other hand, interannual variability is well reconstructed, even when only ~10-years of model grids are used. 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