Climate Dynamics

, Volume 36, Issue 9, pp 2015–2033

A model study of factors influencing projected changes in regional sea level over the twenty-first century


DOI: 10.1007/s00382-009-0738-x

Cite this article as:
Pardaens, A.K., Gregory, J.M. & Lowe, J.A. Clim Dyn (2011) 36: 2015. doi:10.1007/s00382-009-0738-x


In addition to projected increases in global mean sea level over the 21st century, model simulations suggest there will also be changes in the regional distribution of sea level relative to the global mean. There is a considerable spread in the projected patterns of these changes by current models, as shown by the recent Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (AR4). This spread has not reduced from that given by the Third Assessment models. Comparison with projections by ensembles of models based on a single structure supports an earlier suggestion that models of similar formulation give more similar patterns of sea level change. Analysing an AR4 ensemble of model projections under a business-as-usual scenario shows that steric changes (associated with subsurface ocean density changes) largely dominate the sea level pattern changes. The relative importance of subsurface temperature or salinity changes in contributing to this differs from region to region and, to an extent, from model-to-model. In general, thermosteric changes give the spatial variations in the Southern Ocean, halosteric changes dominate in the Arctic and strong compensation between thermosteric and halosteric changes characterises the Atlantic. The magnitude of sea level and component changes in the Atlantic appear to be linked to the amount of Atlantic meridional overturning circulation (MOC) weakening. When the MOC weakening is substantial, the Atlantic thermosteric patterns of change arise from a dominant role of ocean advective heat flux changes.


Sea levelClimate projectionsRegional patternSteric componentsMeridional overturning circulation

Supplementary material

382_2009_738_MOESM1_ESM.pdf (1.3 mb)
Supplementary material (1377 KB)

Copyright information

© Her Majesty the Queen in Rights of the United Kingdom 2010 2010

Authors and Affiliations

  • Anne K. Pardaens
    • 1
  • J. M. Gregory
    • 1
    • 2
  • J. A. Lowe
    • 1
  1. 1.Met Office, Hadley CentreExeterUK
  2. 2.Department of Meteorology, Walker Institute for Climate System ResearchUniversity of ReadingReadingUK