GIA FAQ Updated with Peltier Reference

Edited: 2011-07-29

Regarding the glacial isostatic adjustment (GIA) correction, Professor Dick Peltier, Director of the Centre for Global Change Science at the University of Toronto and one of the leading experts on GIA and its effects on sea level, sent us the initial reference for the GIA correction that we apply to the global mean sea level estimate. The GIA FAQ and 2011_1 release notes have been updated with this reference. Here is Prof. Peltier's view on our applying the GIA correction and the recent attention it has received (hyperlinks added by us):

"...the upward correction of 0.3 mm/yr to the rate of sea level rise being measured by the altimetric satellites Topex/Poseidon and Jason-1 is a correction that was first pointed out as necessary by myself. The initial reference in which this was noted is the following:

Peltier, W.R., 2001, Global glacial isostatic adjustment and modern instrumental records of relative sea level history, on page 80 in chapter 4 of the book Sea level Rise:History and Consequences, Bruce C. Douglas, Michael S. Keaney and Stephen R. Leatherman eds, Academic Press, volume 75 in the International Geophysics Series.

The result was most recently reconfirmed in the following two papers:

Peltier, W.R. and Luthcke, S.B., 2009, On the origins of earth rotation anomalies: new insights on the basis of both "paleogeodetic" data and Gravity Recovery and Climate Experiment (GRACE) data. J. Geophys. Res. 114, B11405, doi:10.1029/2009JB006352.

Peltier, W.R., 2009. Closure of the budget of global sea level rise over the GRACE era. Quat. Sci. Rev., doi:10.1176/2009JCL12481.1 

The physical reason for the necessity of this adjustment to the atimetric satellite measurements of global sea level rise is due to the fact that, due to the large mass of water that was added to the ocean basins during the last deglaciation event of the Late Quaternary ice-age, the ocean basins are continuing to subside of average by this amount.

I'm assuming that the adjustment that Nerem has been making to his analysis of the satellite altimetry observations is this adjustment that I have previously shown to be required. Presumably he has referenced my original papers in deciding to inlcude. It has always been inlcuded in the analyses being perfomed by the group of Anny Cazenave who is the leading European scientist working in this area.

There should be nothing controversial about the necessity of making this correction. Since the need of it was established 10 years ago I'm surprised that it should be attracting attention!"
-- Dick Peltier, June 19, 2011