Abstract
The rise and fall of mean sea level are non-uniform around the global oceans. Their long-term regional trend and variability are intimately linked to the fluctuations and changes in the climate system. In this study, geographical patterns of sea level change derived from altimetric data over the period 1993-2015 were partitioned into large-scale oscillations allied with prevailing climatic factors after an empirical orthogonal function analysis. Taking into account the El Niño–Southern Oscillation (ENSO) and the Pacific Decadal Oscillations (PDO), the sea level change deduced from the multiple regression showed a better estimate than the simple linear regression thanks to significantly larger coefficients of determination and narrower confidence intervals. Regional patterns associated with climatic factors varied greatly in different basins, notably in the eastern and western regions of the Pacific Ocean. The PDO exhibited a stronger impact on long-term spatial change in mean sea level than the ENSO in various parts of the Indian and Pacific Oceans, as well as of the subtropics and along the equator. Further improvements in the signal decomposition technique and physical understanding of the climate system are needed to better attain the signature of climatic factors on regional mean sea level.
Highlights
The global mean sea level (MSL) has been rising since the beginning of the twentieth century (IPCC 2013) and more rapidly during the last 20 years (Chen et al 2017)
The El Niño Southern Oscillation (ENSO) is a major global driver of interannual sea level variability, being prominent in the Pacific Ocean and the Indian Ocean (Landerer et al 2008, Chen et al 2010, Boening et al 2012), which during some extreme events show a local rise in level of approximately 30 cm (Becker et al 2012, McGregor et al 2012, Widlansky et al 2014)
The best model depicting the rates of regional sea level rise is MVLR using the dominant modes of both the Interannual Climate Indices (ICIs) and the Decadal Climate Indices (DCIs) (Fig. 5), which was used to derive the characteristics of regional sea level rise rates to be discussed
Summary
The global mean sea level (MSL) has been rising since the beginning of the twentieth century (IPCC 2013) and more rapidly during the last 20 years (Chen et al 2017). Dating back to the eighteenth century, tide gauge records have long been a source of the spatio-temporal rates of MSL change. Their limitations are sparseness, uneven geographic distribution, high sensitivity to local geodynamic and hydrological influences and, notably, unavailability in the open oceans. In some regions of the western tropical Pacific Ocean, the MSL change rate has been shown to be 3 to 4 times higher than the global rate for the period 1993-2011, thanks to the exploitation of altimetric data (Zhang and Church 2012, Frankcombe et al 2015). We further considered the lagged times to represent the delayed response of climate impact on sea level
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