By the same authors

Constraining 20th-Century Sea-Level Rise in the South Atlantic Ocean

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Published copy (DOI)

Author(s)

  • Thomas Frederikse
  • Surendra Adhikari
  • Tim J. Daley
  • Sönke Dangendorf
  • Roland Gehrels
  • Felix Landerer
  • Marta Marcos
  • Thomas L. Newton
  • Graham Rush
  • Aimée B.A. Slangen
  • Guy Wöppelmann

Department/unit(s)

Publication details

JournalJournal of Geophysical Research: Oceans
DateAccepted/In press - 24 Feb 2021
DateE-pub ahead of print (current) - 12 Mar 2021
Issue number3
Volume126
Early online date12/03/21
Original languageEnglish

Abstract

Sea level in the South Atlantic Ocean has only been measured at a small number of tide-gauge locations, which causes considerable uncertainty in 20th-century sea-level trend estimates in this basin. To obtain a better-constrained sea-level trend in the South Atlantic Ocean, this study aims to answer two questions. The first question is: can we combine new observations, vertical land motion estimates, and information on spatial sampling biases to obtain a likely range of 20th-century sea-level rise in the South Atlantic? We combine existing observations with recovered observations from Dakar and a high-resolution sea-level reconstruction based on salt-marsh sediments from the Falkland Islands and find that the rate of sea-level rise in the South Atlantic has likely been between 1.1 and 2.2 mm year−1 (5%–95% confidence intervals), with a central estimate of 1.6 mm year−1. This rate is on the high side, but not statistically different compared to global-mean trends from recent reconstructions. The second question is: are there any physical processes that could explain a large deviation from the global-mean sea-level trend in the South Atlantic? Sterodynamic (changes in ocean dynamics and steric effects) and gravitation, rotation, and deformation effects related to ice mass loss and land water storage have probably led to a 20th-century sea-level trend in the South Atlantic above the global mean. Both observations and physical processes thus suggest that 20th-century sea-level rise in the South Atlantic has been about 0.3 mm year−1 above the rate of global-mean sea-level rise, although even with the additional observations, the uncertainties are still too large to distinguish a statistically significant difference.

Bibliographical note

© 2021. Jet Propulsion Laboratory, California Institute of Technology. Government sponsorship acknowledged. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

Funding Information:
The idea for this study emerged from the project ?Towards a Unified Sea-Level Record: Assessing the Performance of Global-Mean Sea-Level Reconstructions from Satellite Altimetry, Tide Gauges, Paleo-Proxies and Geophysical Models,? which was funded by the International Space Science Institute (ISSI), Bern Switzerland. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Radiocarbon dating for the Falkland Islands proxy sea-level record was supported by the Natural Environment Research Council Radiocarbon Facility through allocation 1885.0415 (to RG). The authors thank Mark Garnett for help with the interpretation of the chronology and also thank the South Atlantic Environmental Research Institute (SAERI) for logistical support during our stay in the Falkland Islands. SONEL (www.sonel.org) observing system and its associated partners are acknowledged for recovering and making available the historical tide-gauge record of Dakar (and are encouraged to continue the data rescue endeavor). The authors would like to thank Phil Woodworth for sharing the datum information for the Falklands tide-gauge records and Ed Garrett for assisting in the uncertainty analysis of the Swan Inlet data.

Funding Information:
The idea for this study emerged from the project “Towards a Unified Sea‐Level Record: Assessing the Performance of Global‐Mean Sea‐Level Reconstructions from Satellite Altimetry, Tide Gauges, Paleo‐Proxies and Geophysical Models,” which was funded by the International Space Science Institute (ISSI), Bern Switzerland. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Radiocarbon dating for the Falkland Islands proxy sea‐level record was supported by the Natural Environment Research Council Radiocarbon Facility through allocation 1885.0415 (to RG). The authors thank Mark Garnett for help with the interpretation of the chronology and also thank the South Atlantic Environmental Research Institute (SAERI) for logistical support during our stay in the Falkland Islands. SONEL ( www.sonel.org ) observing system and its associated partners are acknowledged for recovering and making available the historical tide‐gauge record of Dakar (and are encouraged to continue the data rescue endeavor). The authors would like to thank Phil Woodworth for sharing the datum information for the Falklands tide‐gauge records and Ed Garrett for assisting in the uncertainty analysis of the Swan Inlet data.

Publisher Copyright:
© 2021. Jet Propulsion Laboratory, California Institute of Technology. Government sponsorship acknowledged.

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

    Research areas

  • data rescue, salt-marsh proxies, sea-level changes, South Atlantic, tide gauges

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