Meteorological controls on sand transport and dune morphology in a polar-desert: Victoria Valley, Antarctica

Johanna Speirs, McGowan, Hamish A. and Neil, David T. (2008) Meteorological controls on sand transport and dune morphology in a polar-desert: Victoria Valley, Antarctica. Earth Surface Processes and Landforms, 33 12: 1875-1891. doi:10.1002/esp.1739


Author Johanna Speirs
McGowan, Hamish A.
Neil, David T.
Title Meteorological controls on sand transport and dune morphology in a polar-desert: Victoria Valley, Antarctica
Journal name Earth Surface Processes and Landforms   Check publisher's open access policy
ISSN 0197-9337
Publication date 2008-01-01
Sub-type Article (original research)
DOI 10.1002/esp.1739
Volume 33
Issue 12
Start page 1875
End page 1891
Total pages 17
Editor Michael J. Kirkby
Place of publication United Kingdom
Publisher John Wiley & Sons Ltd.
Language eng
Subject C1
0406 Physical Geography and Environmental Geoscience
970104 Expanding Knowledge in the Earth Sciences
Formatted abstract
The hyperarid polar desert of the McMurdo Dry Valleys contains an abundance of aeolian sedimentary deposits, the largest in Antarctica, providing a unique setting for studying cold climate aeolian processes and dune morphology. Meteorological controls on sand transport and changes in dune morphology were monitored for 11 days in November-December 2004 on a barchan dune in the Victoria Valley, McMurdo Dry Valleys. Sand transport in this environment was found to be influenced by, (1) interparticle cohesion (ice-bonding); (2) diurnal variations in the speed of thermally driven easterly valley winds due to reduced solar heating by night; and (3) topographically modified foehn southwesterly winds. The threshold entrainment velocity during easterly valleys winds was 5·3 m s-1 (at 0·4 m) ± 0·21 m s-1. Warm, dry and gusty foehn southwesterly winds were found to promote aeolian processes by dislodging surface sediments, with dune morphology responding rapidly. Importantly, no diurnal signal in sand transport was observed under these conditions when wind speed and sand transport occurred independently of solar heating. Measured changes in dune morphology indicate that the dune field of the Victoria Valley under current environmental conditions is in dynamic equilibrium, with frequent up-valley sand transport by thermally generated valley winds balanced by less frequent but greater magnitude down-valley sand transport by moderate to strong foehn southwesterlies. This results in little net movement of dunes and subsequent change in the position of the dune field. Accordingly, we believe that regional-scale shifts in climate that cause change in the synoptic circulation patterns of the Ross Sea region that affect the frequency of either the up-valley easterlies or down-valley foehn winds will result in a net change in the morphology of the Victoria Valley's dune field. Such change in circulation may become apparent early as change in the morphology of the Victoria Valley sand dunes. We therefore suggest this site should be monitored as an indicator site for identifying change in regional weather and climate. Copyright © 2008 John Wiley & Sons, Ltd.
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