Testing past sea level reconstruction methodology (1958-2006)

Abstract

Understanding present-day global sea level rise requires a correct evaluation of past sea level field variability. We use sea level height fields obtained by satellite altimeters between 1992 and 2006, sea level height fields from recent reanalyses of oceanic circulation (SODA) and worldwide tide gauges series for the time interval 1958-2006, to investigate the limitations inherent in reconstructing the past ~50 years of sea level variation using empirical orthogonal function (EOF) decomposition. To understand some of the weaknesses we found, we tested the influence of the spatial distribution of tide gauges as well as the ability to properly reconstruct sea level in certain frequencies bands. The presence of the particularly strong 1997-1998 El Niño event, and the short time span of the base period (1992-2006), limits the determination of other spatial teleconnections and then the reconstruction over preceding epochs. More particularly, during the pre-satellite era and outside the tropics, the non-stationary characteristics of heat transport at interannual time scales and other low frequencies oscillations associated with sea level height fields undermine the methodology. © Springer-Verlag Berlin Heidelberg 2012.