An Anomalous Recent Acceleration of Global Sea Level Rise

• Published in: Journal of climate 2009-11, Vol.22 (21), p.5772-5781
• Main Authors: Merrifield, M. A., Merrifield, S. T., Mitchum, G. T.
• Format: Article
• Language: English
• Subjects: 20th century; Acceleration; Altimeters; Atmospheric aerosols; Climate change; Corrections; Decadal variations; Earth, ocean, space; Enthalpy; Error correction; Estimates; Exact sciences and technology; External geophysics; Gauges; General circulation models; Global sea level; Heat content; Ice; Ice melting; Long-term changes; Marine; Meteorology; Ocean currents; Ocean tides; Oceans; Sampling error; Satellite altimetry; Sea level; Sea level changes; Sea level rise; Sea level trends; Sea level variations; Seas; Segments; Standard error; Tide gauges; Time series; Trends; Tropical climate; Tropical regions; Upper ocean
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/2009jcli2985.1

Tide gauge data are used to estimate trends in global sea level for the period from 1955 to 2007. Linear trends over 15-yr segments are computed for each tide gauge record, averaged over latitude bands, and combined to form an area-weighted global mean trend. The uncertainty of the global trend is specified as a sampling error plus a random vertical land motion component, but land motion corrections do not change the results. The average global sea level trend for the time segments centered on 1962–90 is 1.5 ± 0.5 mm yr−1(standard error), in agreement with previous estimates of late twentieth-century sea level rise. After 1990, the global trend increases to the most recent rate of 3.2 ± 0.4 mm yr−1, matching estimates obtained from satellite altimetry. The acceleration is distinct from decadal variations in global sea level that have been reported in previous studies. Increased rates in the tropical and southern oceans primarily account for the acceleration. The timing of the global acceleration corresponds to similar sea level trend changes associated with upper ocean heat content and ice melt.