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Unabated global mean sea-level rise over the satellite altimeter era

journal contribution
posted on 2023-05-18, 09:49 authored by Christopher WatsonChristopher Watson, White, NJ, Church, JA, Matt KingMatt King, Burgette, RJ, Legresy, B
The rate of global mean sea-level (GMSL) rise has been suggested to be lower for the past decade compared with the preceding decade as a result of natural variability, with an average rate of rise since 1993 of +3.2 ± 0.4 mm yr−1. However, satellite-based GMSL estimates do not include an allowance for potential instrumental drifts (bias drift). Here, we report improved bias drift estimates for individual altimeter missions from a refined estimation approach that incorporates new Global Positioning System (GPS) estimates of vertical land movement (VLM). In contrast to previous results (for example, refs 6,7), we identify significant non-zero systematic drifts that are satellite-specific, most notably affecting the first 6 years of the GMSL record. Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied. These rates are in closer agreement with the rate derived from the sum of the observed contributions, GMSL estimated from a comprehensive network of tide gauges with GPS-based VLM applied (updated from ref. 8) and reprocessed ERS-2/Envisat altimetry. Second, in contrast to the previously reported slowing in the rate during the past two decades, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections, and larger than the twentieth-century acceleration.

History

Publication title

Nature Climate Change

Volume

5

Issue

6

Pagination

565-568

ISSN

1758-678X

Department/School

School of Geography, Planning and Spatial Sciences

Publisher

Nature Publishing Group

Place of publication

United Kingdom

Rights statement

Copyright 2015 Macmillan Publishers Limited

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the earth sciences

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