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Aeolian dynamics over a coastal foredune, Prince Edward Island, Canada
Author(s) -
Hesp Patrick A.,
Walker Ian J.,
Chapman Connie,
DavidsonArnott Robin,
Bauer Bernard O.
Publication year - 2013
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3444
Subject(s) - foredune , geology , aeolian processes , fetch , crest , storm , fault scarp , wind speed , sediment , geomorphology , sediment transport , vegetation (pathology) , hydrology (agriculture) , oceanography , paleontology , geotechnical engineering , medicine , fault (geology) , physics , pathology , quantum mechanics
Near‐surface airflow over a morphologically simple, vegetated, 8 m high foredune with a small wave‐cut scarp was measured for onshore to oblique‐onshore conditions during a low‐moderate (5–6 m s ‐1 ) wind event and a high velocity (11–18 m s ‐1 ) sand‐transporting gale event. Flow across the foredune was characterized by significant flow compression and acceleration up and across the foredune during both events. During the gale, a pronounced jet (speed bulge) developed at the foredune crest, which increased in magnitude with increasing wind speed. The vertical (W) velocity component of the 3D flow field was positive (upwards) across the stoss slope under low wind conditions but negative (downwards) during gale wind conditions, with upslope acceleration. During the low velocity event, there was speed‐down within the vegetation canopy, as would be expected for a porous roughness cover. During the strong wind event there was speed‐up in the lower portion of the vegetation canopy, and this was found up the entire stoss slope. Sediment transport during the gale force event was substantial across the beach and foredune despite the moderate vegetation cover and minimum fetch. Aeolian suspension was evident in the lee of the dune crest. The observations presented herein show that strong storm winds are an effective mechanism for translating sediment landwards across a high vegetated foredune, contributing sediment to the stoss slope, crest and leeward slopes of the foredune and backing dunes. Copyright © 2013 John Wiley & Sons, Ltd.