An Improvement to Short Term Variability in Global Mean Sea Level Reconstruction

Abstract

Substantial efforts in the past two decades have been dedicated to reconstructing global mean sea level changes for the period prior to late 1992 through statistical analysis of sea level observations. We hypothesise that there is an overestimation of Global Mean Sea Level (GMSL) variability from GMSL empirical orthogonal function (EOF) reconstructions due to differences between the tide gauge observations and their corresponding altimetry data. We show that these differences are correlated well with local winds along coastlines, suggesting that observations from tide gauge at the coast and satellite altimetry near the coast are showing some inconsistency. Correcting these differences through a mainly wind-driven regression model prior to the reconstruction, reduces the standard deviation of the reconstructed GMSL variability by 34% and significantly increases the correlation to 0.52 with observed averaged GMSL.

Keywords: Sea Level, satellite altimetry, GMSL, EOF Reconstruction, Variability, Wind