Megadunes in Antarctica: migration and characterization from remote and in situ observations
<p>Megadunes are peculiar features formed by the interaction between the atmosphere and cryosphere and are known to be present only on the East Antarctic Plateau and other planets (Mars and Pluto). In this study, we have analysed the glaciological dynamic of megadunes, their spectral propertie...
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2023-02-01
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Series: | The Cryosphere |
Online Access: | https://tc.copernicus.org/articles/17/427/2023/tc-17-427-2023.pdf |
Summary: | <p>Megadunes are peculiar features formed by the interaction between
the atmosphere and cryosphere and are known to be present only on the East
Antarctic Plateau and other planets (Mars and Pluto). In this study, we have
analysed the glaciological dynamic of megadunes, their spectral properties
and morphology on two sample areas of the East Antarctic Plateau where in
the past international field activities were carried out (EAIIST, East Antarctic International Ice Sheet Traverse;
It-ITASE, Italian International Trans-Antarctic Scientific Expedition). Using satellite images spanning 7 years, we analysed the spatial
and temporal variability in megadune surface characteristics, i.e. near-infrared (NIR) albedo, thermal brightness temperature (BT) and slope along
the prevailing wind direction (SPWD), useful for mapping them. These
parameters allowed us to characterize and perform an automated detection of
the glazed surfaces, and we determined the influence of the SPWD by
evaluating different combinations of these parameters. The inclusion of the
SPWD significantly increased the accuracy of the method, doubling it in
certain analysed scenes. Using remote and field observations, for the first
time we surveyed all the components of upwind migration (absolute,
sedimentological and ice flow), finding an absolute value of about 10 m a<span class="inline-formula"><sup>−1</sup></span>. The analysis shows that the migration is driven by the snow
accumulation on the crest and trough prograding upwind on the previous
windward flanks characterized by glazed surface. Our results present
significant implications for the surface mass balance estimation, paleo-climate
reconstruction using ice cores, and the measurements using optical and
radar images/data in the megadune areas.</p> |
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ISSN: | 1994-0416 1994-0424 |