Ongoing glacial isostatic contributions to observations of sea level change
Studies determining the contribution of water fluxes to sea level rise typically remove the ongoing effects of glacial isostatic adjustment (GIA). Unfortunately, use of inconsistent terminology between various disciplines has caused confusion as to how contributions from GIA should be removed from a...
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fthighwire:oai:open-archive.highwire.org:gji:186/3/1036 2023-05-15T16:41:31+02:00 Ongoing glacial isostatic contributions to observations of sea level change Tamisiea, Mark E. 2011-09-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/186/3/1036 https://doi.org/10.1111/j.1365-246X.2011.05116.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/186/3/1036 http://dx.doi.org/10.1111/j.1365-246X.2011.05116.x Copyright (C) 2011, Oxford University Press Gravity geodesy and tides TEXT 2011 fthighwire https://doi.org/10.1111/j.1365-246X.2011.05116.x 2016-11-16T18:55:50Z Studies determining the contribution of water fluxes to sea level rise typically remove the ongoing effects of glacial isostatic adjustment (GIA). Unfortunately, use of inconsistent terminology between various disciplines has caused confusion as to how contributions from GIA should be removed from altimetry and GRACE measurements. In this paper, we review the physics of the GIA corrections applicable to these measurements and discuss the differing nomenclature between the GIA literature and other studies of sea level change. We then examine a range of estimates for the GIA contribution derived by varying the Earth and ice models employed in the prediction. We find, similar to early studies, that GIA produces a small (compared to the observed value) but systematic contribution to the altimetry estimates, with a maximum range of −0.15 to −0.5 mm yr−1. Moreover, we also find that the GIA contribution to the mass change measured by GRACE over the ocean is significant. In this regard, we demonstrate that confusion in nomenclature between the terms ‘absolute sea level’ and ‘geoid’ has led to an overestimation of this contribution in some previous studies. A component of this overestimation is the incorrect inclusion of the direct effect of the contemporaneous perturbations of the rotation vector, which leads to a factor of ∼two larger value of the degree two, order one spherical harmonic component of the model results. Aside from this confusion, uncertainties in Earth model structure and ice sheet history yield a spread of up to 1.4 mm yr−1 in the estimates of this contribution. However, even if the ice and Earth models were perfectly known, the processing techniques used in GRACE data analysis can introduce variations of up to 0.4 mm yr−1. Thus, we conclude that a single-valued ‘GIA correction’ is not appropriate for sea level studies based on gravity data; each study must estimate a bound on the GIA correction consistent with the adopted data-analysis scheme. Text Ice Sheet HighWire Press (Stanford University) Geophysical Journal International 186 3 1036 1044 |
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Open Polar |
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HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
Gravity geodesy and tides |
spellingShingle |
Gravity geodesy and tides Tamisiea, Mark E. Ongoing glacial isostatic contributions to observations of sea level change |
topic_facet |
Gravity geodesy and tides |
description |
Studies determining the contribution of water fluxes to sea level rise typically remove the ongoing effects of glacial isostatic adjustment (GIA). Unfortunately, use of inconsistent terminology between various disciplines has caused confusion as to how contributions from GIA should be removed from altimetry and GRACE measurements. In this paper, we review the physics of the GIA corrections applicable to these measurements and discuss the differing nomenclature between the GIA literature and other studies of sea level change. We then examine a range of estimates for the GIA contribution derived by varying the Earth and ice models employed in the prediction. We find, similar to early studies, that GIA produces a small (compared to the observed value) but systematic contribution to the altimetry estimates, with a maximum range of −0.15 to −0.5 mm yr−1. Moreover, we also find that the GIA contribution to the mass change measured by GRACE over the ocean is significant. In this regard, we demonstrate that confusion in nomenclature between the terms ‘absolute sea level’ and ‘geoid’ has led to an overestimation of this contribution in some previous studies. A component of this overestimation is the incorrect inclusion of the direct effect of the contemporaneous perturbations of the rotation vector, which leads to a factor of ∼two larger value of the degree two, order one spherical harmonic component of the model results. Aside from this confusion, uncertainties in Earth model structure and ice sheet history yield a spread of up to 1.4 mm yr−1 in the estimates of this contribution. However, even if the ice and Earth models were perfectly known, the processing techniques used in GRACE data analysis can introduce variations of up to 0.4 mm yr−1. Thus, we conclude that a single-valued ‘GIA correction’ is not appropriate for sea level studies based on gravity data; each study must estimate a bound on the GIA correction consistent with the adopted data-analysis scheme. |
format |
Text |
author |
Tamisiea, Mark E. |
author_facet |
Tamisiea, Mark E. |
author_sort |
Tamisiea, Mark E. |
title |
Ongoing glacial isostatic contributions to observations of sea level change |
title_short |
Ongoing glacial isostatic contributions to observations of sea level change |
title_full |
Ongoing glacial isostatic contributions to observations of sea level change |
title_fullStr |
Ongoing glacial isostatic contributions to observations of sea level change |
title_full_unstemmed |
Ongoing glacial isostatic contributions to observations of sea level change |
title_sort |
ongoing glacial isostatic contributions to observations of sea level change |
publisher |
Oxford University Press |
publishDate |
2011 |
url |
http://gji.oxfordjournals.org/cgi/content/short/186/3/1036 https://doi.org/10.1111/j.1365-246X.2011.05116.x |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/186/3/1036 http://dx.doi.org/10.1111/j.1365-246X.2011.05116.x |
op_rights |
Copyright (C) 2011, Oxford University Press |
op_doi |
https://doi.org/10.1111/j.1365-246X.2011.05116.x |
container_title |
Geophysical Journal International |
container_volume |
186 |
container_issue |
3 |
container_start_page |
1036 |
op_container_end_page |
1044 |
_version_ |
1766031967026937856 |