07 Feb 2022
07 Feb 2022
Status: a revised version of this preprint is currently under review for the journal OS.

Attributing decadal climate variability in coastal sea-level trends

Sam Royston1, Rory J. Bingham1, and Jonathan L. Bamber1,2 Sam Royston et al.
  • 1School of Geographical Sciences, University of Bristol, UK
  • 2AI4EO, Technical University Munich, Germany

Abstract. Decadal sea-level variability masks longer-term changes due to natural and anthropogenic drivers in short duration records and increases uncertainty in trend and acceleration estimates. When making regional coastal management and adaptation decisions, it is important to understand the drivers of these changes to account for periods of reduced or enhanced sea-level change. The variance in decadal sea-level trends about the global-mean is quantified and mapped around the global coastlines of the Atlantic, Pacific and Indian Oceans, from historical CMIP6 runs and a high-resolution ocean model forced by reanalysis data. We reconstruct coastal, sea-level trends via linear relationships with climate mode and oceanographic indices. Using this approach, more than one-third of the variability in decadal sea-level trends can be explained by climate indices at 24.6 % to 73.1 % of grid cells located within 25 km of a coast in the Atlantic, Pacific and Indian Oceans. At 10.9 % of the world's coastline, climate variability explains over two-thirds of the decadal sea-level trend. By investigating the steric, manometric and gravitational components of sea-level trend independently, it is apparent that much of the coastal ocean variability is dominated by the manometric signal, the consequence of the open-ocean steric signal propagating on to the continental shelf. Additionally, decadal variability in the GRD signal should not be ignored in the total. There are locations such as the Persian Gulf and African west coast where decadal sea level variability is historically small, that are susceptible to future changes in hydrology and/or ice mass changes that drive intensified regional GRD sea-level change above the global-mean. The magnitude of variance explainable by climate modes quantified in this study infers an enhanced uncertainty on projections of short- to mid-term regional sea-level trend.

Sam Royston et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on os-2022-3', Anonymous Referee #1, 07 Mar 2022
    • AC1: 'Reply on RC1', Samantha Royston, 09 May 2022
  • RC2: 'Comment on os-2022-3', Anonymous Referee #2, 08 Mar 2022
    • AC2: 'Reply on RC2', Samantha Royston, 09 May 2022
  • RC3: 'Comment on os-2022-3', Julia Pfeffer, 22 Mar 2022
    • AC3: 'Reply on RC3', Samantha Royston, 09 May 2022

Sam Royston et al.

Data sets

Attributing decadal climate variability in coastal sea-level trends Royston, Bingham, Bamber

Sam Royston et al.


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Latest update: 27 May 2022
Short summary
Decadal sea-level variability masks longer-term changes and increases uncertainty in observed trend and acceleration estimates. We use numerical ocean models to determine the magnitude of decadal variability we might expect in sea-level trends at coastal locations around the world, resulting from natural, internal variability. A good proportion of that variability can be replicated from known climate modes, giving projection uncertainty for short- to mid-term regional sea-level trend.