Geographic Variability of Sea-Level Change

Abstract

Local sea-level changes differ significantly from global-mean sea-level change as a result of (1) non-climatic, geological background processes; (2) atmosphere/ocean dynamics; and (3) the gravitational, elastic, and rotational "fingerprint" effects of ice and ocean mass redistribution. Though the research communities working on these different effects each have a long history, the integration of all these different processes into interpretations of past changes and projections of future change is an active area of research. Fully characterizing the past contributions of these processes requires information from sources covering a range of timescales, including geological proxies, tide-gauge observations from the last~3 centuries, and satellite-altimetry data from the last~2 decades. Local sea-level rise projections must account for the different spatial patterns of different processes, as well as potential correlations between different drivers.

Temperature-driven global sea-level variability in the Common Era

“…The three components are (i) GSL gðtÞ, which is common across all sites and primarily represents contributions from thermal expansion and changing land ice volume; (ii) a regionally varying, temporally linear field lðxÞðt − t 0 Þ, which represents slowly changing processes such as GIA, tectonics, and natural sediment compaction; and (iii) a regionally varying, temporally nonlinear field mðx, tÞ, which primarily represents factors such as ocean/atmosphere dynamics (16) and static equilibrium "fingerprint" effects of land−ice mass balance changes (17,18). The regional nonlinear field also incorporates small changes in rates of GIA, tectonics, and compaction that occur over the Common Era.…”

Simulation of the Greenland Ice Sheet over two glacial–interglacial cycles: investigating a sub-ice- shelf melt parameterization and relative sea level forcing in an ice-sheet–ice-shelf model

“…However, sea level variations are in fact not simply GMSL (i.e. with no spatial variations), but vary spatially due to numerous processes that dominate over different timescales, with GIA the dominant process on the timescales of this study (Kopp et al, 2015;Rovere et al, 2016).…”

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

“…These results suggest that the decadal sea level patterns associated with the PDO and NPGO, which are dominated by the upper-ocean thermosteric sea level (e.g., Lombard et al 2005), result primarily from changes in winddriven ocean circulation, with surface heat and freshwater fluxes playing a minor role in the North Pacific Ocean. Indeed, the dominance of wind-driven ocean circulation in causing regional distributions of decadal sea level variability has been demonstrated, and the thermosteric and halosteric sea level components often have compensating effects due to heat and salt redistribution by advection [see reviews by Stammer et al (2013) and Kopp et al (2015)]. …”

“…Various factors can cause sea level to change at regional or local scales (e.g., Stammer et al 2013): changes in atmospheric and oceanic circulations (often referred to as dynamic change), large-scale deformation of ocean basins, variation in Earth's gravity field and local land movement (e.g., Church et al 2013;Stammer et al 2013;Kopp et al 2015). Dynamic sea level change induced by changes in atmospheric and oceanic circulations is a major cause for contemporary decadal sea level variability as opposed to long-term anthropogenic changes, and a large fraction of the dynamic sea level change can be associated with natural internal climate modes in the Earth's coupled climate system .…”