Long-Term Sea-Level Change Revisited: The role of salinity

TitleLong-Term Sea-Level Change Revisited: The role of salinity
Publication TypeJournal Article
Year of Publication2014
AuthorsDurack, Paul J., Wijffels Susan E., and Gleckler Peter J.
JournalEnvironmental Research Letters
Volume9
Number11
Pages114017
Date Published11/2014
Abstract / Summary

Of the many processes contributing to long-term sea-level change, little attention has been paid to the large-scale contributions of salinity-driven halosteric changes. We evaluate observed and simulated estimates of long-term (1950-present) halosteric patterns and compare these to corresponding thermosteric changes. Spatially coherent halosteric patterns are visible in the historical record, and are consistent with estimates of long-term water cycle amplification. Our results suggest that long-term basin-scale halosteric changes in the Pacific and Atlantic are substantially larger than previously assumed, with observed estimates and coupled climate models suggesting magnitudes of ~25% of the corresponding thermosteric changes. In both observations and simulations, Pacific basin-scale freshening leads to a density reduction that augments coincident thermosteric expansion, whereas in the Atlantic halosteric changes partially compensate strong thermosteric expansion via a basin-scale enhanced salinity density increase. Although regional differences are apparent, at basin-scales consistency is found between the observed and simulated partitioning of halosteric and thermosteric changes, and suggests that models are simulating the processes driving observed long-term basin-scale steric changes. Further analysis demonstrates that the observed halosteric changes and their basin partitioning are consistent with CMIP5 simulations that include anthropogenic CO2 forcings (Historical), but are found to be inconsistent with simulations that exclude anthropogenic forcings (HistoricalNat).

URLhttp://iopscience.iop.org/1748-9326/9/11/114017/
DOI10.1088/1748-9326/9/11/114017
Journal: Environmental Research Letters
Year of Publication: 2014
Volume: 9
Number: 11
Pages: 114017
Date Published: 11/2014

Of the many processes contributing to long-term sea-level change, little attention has been paid to the large-scale contributions of salinity-driven halosteric changes. We evaluate observed and simulated estimates of long-term (1950-present) halosteric patterns and compare these to corresponding thermosteric changes. Spatially coherent halosteric patterns are visible in the historical record, and are consistent with estimates of long-term water cycle amplification. Our results suggest that long-term basin-scale halosteric changes in the Pacific and Atlantic are substantially larger than previously assumed, with observed estimates and coupled climate models suggesting magnitudes of ~25% of the corresponding thermosteric changes. In both observations and simulations, Pacific basin-scale freshening leads to a density reduction that augments coincident thermosteric expansion, whereas in the Atlantic halosteric changes partially compensate strong thermosteric expansion via a basin-scale enhanced salinity density increase. Although regional differences are apparent, at basin-scales consistency is found between the observed and simulated partitioning of halosteric and thermosteric changes, and suggests that models are simulating the processes driving observed long-term basin-scale steric changes. Further analysis demonstrates that the observed halosteric changes and their basin partitioning are consistent with CMIP5 simulations that include anthropogenic CO2 forcings (Historical), but are found to be inconsistent with simulations that exclude anthropogenic forcings (HistoricalNat).

DOI: 10.1088/1748-9326/9/11/114017
Citation:
Durack, PJ, SE Wijffels, and PJ Gleckler.  2014.  "Long-Term Sea-Level Change Revisited: The role of salinity."  Environmental Research Letters 9(11): 114017.  https://doi.org/10.1088/1748-9326/9/11/114017.