Proper orthogonal decomposition of ice velocity identifies drivers of flow variability at Sermeq Kujalleq (Jakobshavn Isbræ)
-
Published:2022-01-21
Issue:1
Volume:16
Page:219-236
-
ISSN:1994-0424
-
Container-title:The Cryosphere
-
language:en
-
Short-container-title:The Cryosphere
Author:
Ashmore David W.ORCID, Mair Douglas W. F., Higham Jonathan E.ORCID, Brough StephenORCID, Lea James M.ORCID, Nias Isabel J.ORCID
Abstract
Abstract. The increasing volume and spatio-temporal resolution of
satellite-derived ice velocity data have created new exploratory
opportunities for the quantitative analysis of glacier dynamics. One
potential technique, proper orthogonal decomposition (POD), also known as
empirical orthogonal functions, has proven to be a powerful and flexible
technique for revealing coherent structures in a wide variety of
environmental flows. In this study we investigate the applicability of POD
to an openly available TanDEM-X/TerraSAR-X-derived ice velocity dataset from
Sermeq Kujalleq (Jakobshavn Isbræ), Greenland. We find three dominant
modes with annual periodicity that we argue are explained by glaciological
processes. The primary dominant mode is interpreted as relating to the
stress reconfiguration at the glacier terminus, known to be an important
control on the glacier's dynamics. The second and third largest modes
together relate to the development of the spatially heterogenous glacier
hydrological system and are primarily driven by the pressurisation and
efficiency of the subglacial hydrological system. During the melt season,
variations in the velocity shown in these two subsidiary modes are explained
by the drainage of nearby supraglacial melt ponds, as identified with a
Google Earth Engine Moderate Resolution Imaging Spectroradiometer (MODIS) dynamic thresholding technique. By isolating
statistical structures within velocity datasets and through their
comparison to glaciological theory and complementary datasets, POD indicates
which glaciological processes are responsible for the changing bulk velocity
signal, as observed from space. With the proliferation of optical- and radar-derived velocity products (e.g. MEaSUREs, ESA CCI, PROMICE), we suggest POD,
and potentially other modal decomposition techniques, will become
increasingly useful in future studies of ice dynamics.
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Water Science and Technology
Reference69 articles.
1. Albidah, A. B., Brevis, W., Fedun, V., Ballai, I., Jess, D. B., Stangalini,
M., Higham, J., and Verth G.: Proper orthogonal and dynamic mode
decomposition of sunspot data, Philos. T. R. Soc. A., 379, 20200181,
https://doi.org/10.1098/rsta.2020.0181, 2020. 2. Andrews, L. C., Catania, G. A, Hoffman, M. J., Gulley, J. D., Lüthi, M.
P., Ryser, C., Hawley, R. L., and Neumann, T. A.: Direct observations of
evolving subglacial drainage beneath the Greenland Ice Sheet, Nature, 514,
80–83, https://doi.org/10.1038/nature13796, 2014. 3. Ashmore, D. W.: Proper Othogonal Decomposition of SAR-derived ice velocity – Data and Code, Version 1.0.0, Zenodo [data set], https://doi.org/10.5281/zenodo.4699392, 2021. 4. Bevan, S. L., Luckman, A. J., Benn, D. I., Cowton, T., and Todd, J.: Impact of warming shelf waters on ice mélange and terminus retreat at a large SE Greenland glacier, The Cryosphere, 13, 2303–2315, https://doi.org/10.5194/tc-13-2303-2019, 2019. 5. Bian, Y., Yue, J., Gao, W., Li, Z., Lu, D., Xiang, Y., and Chen, J.: Analysis of the Spatiotemporal Changes of Ice Sheet Mass and Driving Factors in
Greenland, Remote Sens., 11, 862, https://doi.org/10.3390/rs11070862, 2019.
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|