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Drivers of ASCAT C band backscatter variability in the dry snow zone of Antarctica

Citation

Fraser, AD and Nigro, MA and Ligtenberg, SRM and Legresy, B and Inoue, M and Cassano, JJ and Kuipers Munneke, P and Lenaerts, JTM and Young, NW and Treverrow, A and van den Broeke, M and Enomoto, H, Drivers of ASCAT C band backscatter variability in the dry snow zone of Antarctica, Journal of Glaciology, 62, (231) pp. 170-184. ISSN 0022-1430 (2016) [Refereed Article]


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Copyright Statement

Copyright 2016 The Authors. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons. org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

DOI: doi:10.1017/jog.2016.29

Abstract

C band backscatter parameters contain information about the upper snowpack/firn in the dry snow zone. The wide incidence angle diversity of the Advanced Scatterometer (ASCAT) gives unprecedented characterisation of backscatter anisotropy, revealing the backscatter response to climatic forcing. The A (isotropic component) and M2 (bi-sinusoidal azimuth anisotropy) parameters are investigated here, in conjunction with data from atmospheric and snowpack models, to identify the backscatter response to surface forcing parameters (wind speed and persistence, precipitation, surface temperature, density and grain size). The long-term mean A parameter is successfully recreated with a regression using these drivers, indicating strong links between the A parameter and precipitation on long timescales. While the ASCAT time series is too short to determine which factors drive observed trends, factors influencing the seasonal and short timescale variability are revealed. On these timescales, A strongly responds to the propagation of surface temperature cycles/anomalies downward through the firn, via direct modulation of the dielectric constant. The influence of precipitation on A is small at shorter timescales. The M2 parameter is controlled by wind speed and persistence, through modification of monodirectionally-aligned surface roughness. This variability indicates that throughout much of coastal Antarctica, a microwave ‘snapshot’ is generally not representative of longer-term conditions.

Item Details

Item Type:Refereed Article
Keywords:ASCAT, Antarctic ice sheet, dry snow zone, backscatter, anisotropy, precipitation, firn temperature, snow, Antarctica, remote sensing, microwave scatterometer
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Glaciology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Fraser, AD (Dr Alex Fraser)
Author:Legresy, B (Dr Benoit Legresy)
Author:Inoue, M (Ms Mana Inoue)
Author:Young, NW (Mr Neal Young)
Author:Treverrow, A (Dr Adam Treverrow)
ID Code:104722
Year Published:2016
Web of Science® Times Cited:1
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2015-11-18
Last Modified:2017-10-30
Downloads:64 View Download Statistics

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