Ocean bottom deformation due to present-day mass redistribution and its impact on sea level observations

• Published in: Geophysical Research Letters
• Main Authors: Frederikse, T, Riva, REM, King, MA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2017
• Subjects: vertical land movement; ice melt; sea level; altimetry; tide gauges; Arctic; Arctic Ocean
• Online Access: https://eprints.utas.edu.au/39035/; https://eprints.utas.edu.au/39035/2/122584%20-%20Ocean%20bottom%20deformation%20due%20to%20present-day%20mass%20redistribution%20and%20its%20impact%20on%20sea-level%20observations.pdf; https://doi.org/10.1002/2017GL075419

Present-day mass redistribution increases the total ocean mass and, on average, causes the ocean bottom to subside elastically. Therefore, barystatic sea-level rise is larger than the resulting global-mean geocentric sea-level rise,observed by satellite altimetry and GPS-corrected tide gauges. We use realistic estimates of mass redistribution from ice-mass loss and land-water storage to quantify the resulting ocean-bottom deformation and its effect on global and regional ocean-volume change estimates. Over 1993-2014, the resulting globally-averaged geocentric sea-level change is 8 percent smaller than the barystatic contribution. Over the altimetry domain, the difference is about 5 percent, and due to this effect, barystatic sea-level rise will be underestimated by more than 0.1 mm/y over 1993 -2014. Regional differences are of-ten larger: up to 1 mm/y over the Arctic Ocean and 0.4 mm/y in the South Pacific. Ocean bottom deformation should be considered when regional sea-level changes are observed in a geocentric reference frame.