nerc.ac.uk

Spatiotemporal interpolation of elevation changes derived from satellite altimetry for Jakobshavn Isbræ, Greenland

Hurkmans, R.T.W.L.; Bamber, J.L.; Sørensen, L.S.; Joughin, I.R.; Davis, C.H.; Krabill, W.B.. 2012 Spatiotemporal interpolation of elevation changes derived from satellite altimetry for Jakobshavn Isbræ, Greenland. Journal of Geophysical Research, 117 (F3), F03001. 16, pp. 10.1029/2011JF002072

Before downloading, please read NORA policies.
[img]
Preview
Text
2011JF002072.pdf - Published Version

Download (4MB) | Preview

Abstract/Summary

Estimation of ice sheet mass balance from satellite altimetry requires interpolation of point-scale elevation change (dH/dt) data over the area of interest. The largest dH/dt values occur over narrow, fast-flowing outlet glaciers, where data coverage of current satellite altimetry is poorest. In those areas, straightforward interpolation of data is unlikely to reflect the true patterns of dH/dt. Here, four interpolation methods are compared and evaluated over Jakobshavn Isbræ, an outlet glacier for which widespread airborne validation data are available from NASA's Airborne Topographic Mapper (ATM). The four methods are ordinary kriging (OK), kriging with external drift (KED), where the spatial pattern of surface velocity is used as a proxy for that of dH/dt, and their spatiotemporal equivalents (ST-OK and ST-KED). KED assumes a linear relationship between spatial gradients of velocity and dH/dt, which is confirmed for both negative (Pearson's correlation ρ < −0.85) and, to a lesser degree, positive (ρ = 0.73) dH/dt values. When compared to ATM data, KED and ST-KED yield more realistic spatial patterns and higher thinning rates (over 20 m yr−1 as opposed to 7 m yr−1 for OK). Spatiotemporal kriging smooths inter-annual variability and improves interpolation in periods with sparse data coverage and we conclude, therefore, that ST-KED produces the best results. Using this method increases volume loss estimates from Jakobshavn Isbræ by up to 20% compared to those obtained by OK. The proposed interpolation method will improve ice sheet mass balance reconstructions from existing and past satellite altimeter data sets, with generally poor sampling of outlet glaciers.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2011JF002072
Programmes: BAS Programmes > EU:Ice2Sea
ISSN: 0148-0227
Date made live: 13 Dec 2012 11:42 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/20800

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...