气候变化领域集成服务门户(CCPortal): Differential interferometric synthetic aperture radar for tide modelling in Antarctic ice-shelf grounding zones

CCPortal

DOI	10.5194/tc-13-3171-2019
	Differential interferometric synthetic aperture radar for tide modelling in Antarctic ice-shelf grounding zones
	Wild T.C.; Marsh J.O.; Rack W.
发表日期	2019
ISSN	19940416
EISSN	13
起始页码	3171
结束页码	3191
卷号	13 期号:12
英文摘要	Differential interferometric synthetic aperture radar (DInSAR) is an essential tool for detecting ice-sheet motion near Antarctica's oceanic margin. These space-borne measurements have been used extensively in the past to map the location and retreat of ice-shelf grounding lines as an indicator for the onset of marine ice-sheet instability and to calculate the mass balance of ice sheets and individual catchments. The main difficulty in interpreting DInSAR is that images originate from a combination of several SAR images and do not indicate instantaneous ice deflection at the times of satellite data acquisitions. Here, we combine the sub-centimetre accuracy and spatial benefits of DInSAR with the temporal benefits of tide models to infer the spatio-temporal dynamics of ice-ocean interaction during the times of satellite overpasses. We demonstrate the potential of this synergy with TerraSAR-X data from the almost-stagnant southern McMurdo Ice Shelf (SMIS). We then validate our algorithm with GPS data from the fast-flowing Darwin Glacier, draining the Antarctic Plateau through the Transantarctic Mountains into the Ross Sea. We are able to reconstruct DInSAR-derived vertical displacements to 7 mm mean absolute residual error and generally improve traditional tide-model output by up to 39 % from 10.8 to 6.7 cm RMSE against GPS data from areas where ice is in local hydrostatic equilibrium with the ocean and by up to 74 % from 21.4 to 5.6 cm RMSE against GPS data in feature-rich coastal areas where tide models have not been applicable before. Numerical modelling then reveals Young's modulus of $E Combining double low line 1.0 \pm 0.56$ GPa and an ice viscosity of $ν Combining double low line 10 \pm 3.65$ TPa s when finite-element simulations of tidal flexure are matched to 16 d of tiltmeter data, supporting the hypothesis that strain-dependent anisotropy may significantly decrease effective viscosity compared to isotropic polycrystalline ice on large spatial scales. Applications of our method include the following: refining coarsely gridded tide models to resolve small-scale features at the spatial resolution and vertical accuracy of SAR imagery, separating elastic and viscoelastic contributions in the satellite-derived flexure measurement, and gaining information about large-scale ice heterogeneity in Antarctic ice-shelf grounding zones, the missing key to improving current ice-sheet flow models. The reconstruction of the individual components forming DInSAR images has the potential to become a standard remote-sensing method in polar tide modelling. Unlocking the algorithm's full potential to answer multi-disciplinary research questions is desired and demands collaboration within the scientific community. © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
学科领域	GPS; ice shelf; ice-ocean interaction; interferometry; modeling; reconstruction; remote sensing; satellite data; satellite imagery; spatial resolution; synthetic aperture radar; TerraSAR-X; Antarctic Plateau; Antarctica; Darwin Glacier; East Antarctica; McMurdo Ice Shelf; Ross Sea; Southern Ocean; Transantarctic Mountains
语种	英语
scopus关键词	GPS; ice shelf; ice-ocean interaction; interferometry; modeling; reconstruction; remote sensing; satellite data; satellite imagery; spatial resolution; synthetic aperture radar; TerraSAR-X; Antarctic Plateau; Antarctica; Darwin Glacier; East Antarctica; McMurdo Ice Shelf; Ross Sea; Southern Ocean; Transantarctic Mountains
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118801
作者单位	Gateway Antarctica, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand; British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, United Kingdom
推荐引用方式 GB/T 7714	Wild T.C.,Marsh J.O.,Rack W.. Differential interferometric synthetic aperture radar for tide modelling in Antarctic ice-shelf grounding zones[J],2019,13(12).
APA	Wild T.C.,Marsh J.O.,&Rack W..(2019).Differential interferometric synthetic aperture radar for tide modelling in Antarctic ice-shelf grounding zones.The Cryosphere,13(12).
MLA	Wild T.C.,et al."Differential interferometric synthetic aperture radar for tide modelling in Antarctic ice-shelf grounding zones".The Cryosphere 13.12(2019).