Towards the inversion of GRACE gravity fields for present-day ice-mass changes and glacial-isostatic adjustment in North America and Greenland

Sasgen, Ingo; Klemann, Volker; Martinec, Zdeněk. 2012 Towards the inversion of GRACE gravity fields for present-day ice-mass changes and glacial-isostatic adjustment in North America and Greenland. Journal of Geodynamics, 59-60. 49-63. 10.1016/j.jog.2012.03.004

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Official URL: http://dx.doi.org/10.1016/j.jog.2012.03.004

Abstract/Summary

We perform an inversion of gravity fields from the Gravity Recovery and Climate Experiment (GRACE) (August 2002 to August 2009) of four processing centres for glacial-isostatic adjustment (GIA) over North America and present-day ice-mass change in Alaska and Greenland. We apply a statistical filtering approach to reduce noise in the GRACE data by confining our investigations to GRACE coefficients containing a statistically significant linear trend. Selecting the subset of reliable coefficients in all GRACE time series (GFZ RL04, ITG 2010, JPL RL04 and CSR RL04) results in a non-isotropic smoothing of the GRACE gravity fields, which is effective in reducing the north-south oriented striping associated with correlated errors in GRACE coefficients. In a next step, forward models of GIA induced by the glacial history NAWI (Zweck and Huybrechts, 2005), as well as present-day ice mass changes in Greenland from ICESat (Sørensen et al., 2011) and Alaska from airborne laser altimetry (Arendt et al., 2002) are simultaneously adjusted in scale to minimize the misfit to the filtered GRACE trends. From the adjusted models, we derive the recent sea-level contributions for Greenland and Alaska (August 2002 to August 2009), and, interpret the residual misfit over the GIA-dominated region around the Hudson Bay, Canada, in terms of mantle viscosities beneath North America.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.jog.2012.03.004
Programmes:	NOC Programmes
ISSN:	02643707
Additional Keywords:	Greenland; GRACE; Glacial-isostatic adjustment; Mantle viscosity; Joint inversion; Ice-mass balance; Glacial history
NORA Subject Terms:	Marine Sciences
Date made live:	03 Oct 2012 12:27 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/19838

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.jog.2012.03.004

Programmes:

NOC Programmes

ISSN:

02643707

Additional Keywords:

Greenland; GRACE; Glacial-isostatic adjustment; Mantle viscosity; Joint inversion; Ice-mass balance; Glacial history

NORA Subject Terms:

Marine Sciences