In-situ quantification of ice rheology and direct measurement of the Raymond Effect at Summit, Greenland using a phase-sensitive radar

Gillet-Chaulet, Fabien; Hindmarsh, Richard C.A. ORCID: https://orcid.org/0000-0003-1633-2416; Corr, Hugh F.J.; King, Edward C. ORCID: https://orcid.org/0000-0003-3793-3915; Jenkins, Adrian ORCID: https://orcid.org/0000-0002-9117-0616. 2011 In-situ quantification of ice rheology and direct measurement of the Raymond Effect at Summit, Greenland using a phase-sensitive radar. Geophysical Research Letters, 38 (24), L24503. 6, pp. 10.1029/2011GL049843

Before downloading, please read NORA policies.

[thumbnail of Copyright American Geophysical Union]

Preview

Text (Copyright American Geophysical Union)
grl28735.pdf - Published Version
Download (404kB) | Preview

Official URL: http://www.agu.org/journals/gl/gl1124/2011GL049843...

Abstract/Summary

The Glen exponent ncharacterizes the stress-dependence of ice deformation, directly influencing the rate at which ice masses respond to external forcing. The slow deformation in large ice-sheets makes laboratory rheometry at representative strain-rates difficult. We develop a new technique to estimaten in-situ, deploying a phase-sensitive radar to measure vertical strain rates of around 10−4 yr−1within the top 1000 m of ice across ice divides at Summit and NEEM, Greenland. A fluid-dynamical feature, the Raymond Effect, predicts strong vertical strain-rate variation across divides over distances of a few ice-thicknesses. We achieve sufficient resolution to show this pattern, enabling us to estimaten= 4.5 by inverting our observations with flow modelling. This is higher than values previously used but consistent with other indirect measurements, implying laboratory measurements do not explore the full range of ice rheology and the consequent possibility of a greater sensitivity and responsiveness in ice-sheet dynamics.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2011GL049843
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Ice Sheets
ISSN:	0094-8276
Date made live:	26 Jan 2012 10:31 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/16519

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2011GL049843

Programmes:

BAS Programmes > Polar Science for Planet Earth (2009 - ) > Ice Sheets

ISSN:

0094-8276

Date made live:

26 Jan 2012 10:31 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/16519