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Can We Resolve the Basin‐Scale Sea Level Trend Budget From GRACE Ocean Mass?
Author(s) -
Royston Sam,
Dutt Vishwakarma Bramha,
Westaway Richard,
Rougier Jonathan,
Sha Zhe,
Bamber Jonathan
Publication year - 2020
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2019jc015535
Subject(s) - sea level , scale (ratio) , altimeter , climatology , satellite , structural basin , environmental science , oceanic basin , post glacial rebound , geology , geodesy , geography , oceanography , cartography , paleontology , aerospace engineering , engineering
Understanding sea level changes at a regional scale is important for improving local sea level projections and coastal management planning. Sea level budget (SLB) estimates derived from the sum of observation of each component close for the global mean. The sum of steric and Gravity Recovery and Climate Experiment (GRACE) ocean mass contributions to sea level calculated from measurements does not match the spatial patterns of sea surface height trends from satellite altimetry at 1° grid resolution over the period 2005–2015. We investigate potential drivers of this mismatch aggregating to subbasin regions and find that the steric plus GRACE ocean mass observations do not represent the small‐scale features seen in the satellite altimetry. In addition, there are discrepancies with large variance apparent at the global and hemispheric scale. Thus, the SLB closure on the global scale to some extent represents a cancelation of errors. The SLB is also sensitive to the glacial isostatic adjustment correction for GRACE and to altimery orbital altitude. Discrepancies in the SLB are largest for the Indian‐South Pacific Ocean region. Taking the spread of plausible sea level trends, the SLB closes at the ocean‐basin scale ( 2 σ ) but with large spread of magnitude, one third or more of the trend signal. Using the most up‐to‐date observation products, our ocean‐region SLB does not close everywhere, and consideration of systematic uncertainties diminishes what information can be gained from the SLB about sea level processes, quantifying contributions, and validating Earth observation systems.