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Fast-ice distribution in East Antarctica during 1997 and 1999 determined using RADARSAT data

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posted on 2023-05-19, 22:31 authored by Alan Giles, Robert MassomRobert Massom, Lytle, VI

[1] We present the first detailed maps of fast ice around East Antarctica (75°E–170°E), using an image correlation technique applied to RADARSAT ScanSAR images from November in 1997 and 1999. This method is based upon searching for, and distinguishing, correlated regions of the ice‐covered ocean which remain stationary, in contrast to adjacent moving pack ice. Within the overlapping longitudinal range of ∼86°E–150.6°E, the total fast‐ice area is 141,450 km2 in 1997 and 152,216 km2 in 1999. Calibrated radar backscatter data are also used to determine the distribution of two fast‐ice classes based on their surface roughness characteristics. These are “smooth” fast ice (−25.4 dB to −13.5 dB) and “rough” fast ice (−13.5 dB to −2.5 dB). The former comprises ∼67% of the total area, with rough fast ice making up the remaining ∼33%. An estimate is made of fast‐ice volume, on the basis of fast‐ice type as a proxy measure of ice thickness and area. Results suggest that although fast ice forms 2–16% of the total November sea ice area for this sector of East Antarctica in 1997 and 1999 (average 8.3% across maps), it may comprise 6–57% of the total ice volume (average ∼28% across maps). Grounded icebergs play a key role in fast‐ice distribution in all regions apart from 150°E–170°E. These are “snapshot” estimates only, and more work is required to determine longer‐term spatiotemporal variability.

History

Publication title

Journal of Geophysical Research: Oceans

Volume

113

Issue

C2

Article number

C02S14

Number

C02S14

Pagination

1-15

ISSN

0148-0227

Department/School

Institute for Marine and Antarctic Studies

Publisher

Amer Geophysical Union

Place of publication

2000 Florida Ave Nw, Washington, USA, Dc, 20009

Rights statement

Copyright 2008 American Geophysical Union

Repository Status

  • Open

Socio-economic Objectives

Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts); Expanding knowledge in the physical sciences

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