Global Sea Level Variations Estimated from Satellite Altimetry, GRACE and Oceanographic Data

In this paper, global sea level variations and the influence on the sea level rise from Antarctic ice sheet and Greenland ice sheet ablation from 2003 to 2012 are estimated from satellite altimetry, GRACE and oceanographic data. From 2003 to 2012, global sea level rose with the rate at 2.72±0.07 mm/a and spatial distribution characteristics estimated from altimetry. Ocean mass changes estimated from GRACE accounted for 66% of the sea level change, with the rate at 1.80±0.10mm/a, and steric sea level changes accounted for 34% of the sea level change with the rate at 0.93±0.05 mm/a estimated from Argo and accounted for 19% of the sea level change with the rate at 0.51±0.03 mm/a estimated from Ishii. Meanwhile, global sea level, steric sea level and oceanic mass variations had significant seasonal characteristics, with the annual cycle amplitude 4.6±0.3 mm, 4.1±0.2 mm, 3.6±0.1 mm and 7.3±0.4 mm, respectively, estimated from altimetry, Argo, Ishii and GRACE. Using empirical orthogonal function (EOF) analysis, we found significant seasonal differences existed between the northern and southern hemispheres in global sea level, steric sea level, but did not exist in oceanic mass changes. The rates of Antarctica ice sheet and Greenland ice sheet ablation were -75.7±12.3 Gt/a and -124.1±2.9 Gt/a from 2003 to 2012, respectively. And the correspondent global sea level rising rates were 0.21±0.03 mm/a, 0.34±0.01 mm/a, which can only accounted for 12% and 19%, total up to only 31% of the ocean mass increase. So the melting of the polar ice sheet was not the most important factor in the increase of ocean mass from 2003 to 2012.