TY - JOUR
T1 - Assessment of highly active dune mobility in the medium, short and very short term
AU - Navarro, Marina
AU - Muñoz-Pérez, Juan J.
AU - Román-Sierra, Jorge
AU - Tsoar, Haim
AU - Rodríguez, Inmaculada
AU - Gómez-Pina, Gregorio
N1 - Funding Information:
The authors wish to thank the Coastal Department of Andalucia-Atlantico, which belongs to the Spanish Ministry of Environment, and the Spanish Meteorology Agency (AEMET) for providing useful information for the development of this research.
PY - 2011/6/1
Y1 - 2011/6/1
N2 - Dune activity or stability has usually been studied over long time periods; however, this may not reflect changes that occur in the short term, especially for highly active dunefields. Extreme wind conditions that are generated near the Strait of Gibraltar (SW Spain) have given rise to the transgressive Valdevaqueros dunefield. The current work focuses on analyzing the sand drift potential and the evolution of the dune profile in the medium term (months), the short term (days) and the very short term (hours). Topographic data, which were collected with a differential GPS, were interpreted from reconstructed empirical orthogonal functions (EOF). The results showed that generally the dune profile presented shifting morphologies, especially around the crest and brink, and a trend towards migration to a gentler steady state. As a result, the leeward side adopted continuous slope variations during the different survey periods, whereas the windward slope did not undergo any significant change. Lateral and vertical displacements were analyzed during a severe easterly sandstorm, when the dune brink experienced an advance migration rate of 1.75m in 24h. Sand transport rates of 25.5-36.5m3 m-1 month-1, 22.52m3 m-1 day-1 and 0.93m3 m-1 h-1 were measured for the medium term, short term and very short term, respectively. These values were compared to the theoretical sand transport rate for Valdevaqueros dune, based on the classic Bagnold equation as well other more recent formulae, to obtain a ratio between the real and the theoretical rates for each study period. These results together with the sand drift potential (up to 10,000 vector units) demonstrate that Valdevaqueros (Tarifa) is a dunefield with one of the highest sand transport capacities in Europe.
AB - Dune activity or stability has usually been studied over long time periods; however, this may not reflect changes that occur in the short term, especially for highly active dunefields. Extreme wind conditions that are generated near the Strait of Gibraltar (SW Spain) have given rise to the transgressive Valdevaqueros dunefield. The current work focuses on analyzing the sand drift potential and the evolution of the dune profile in the medium term (months), the short term (days) and the very short term (hours). Topographic data, which were collected with a differential GPS, were interpreted from reconstructed empirical orthogonal functions (EOF). The results showed that generally the dune profile presented shifting morphologies, especially around the crest and brink, and a trend towards migration to a gentler steady state. As a result, the leeward side adopted continuous slope variations during the different survey periods, whereas the windward slope did not undergo any significant change. Lateral and vertical displacements were analyzed during a severe easterly sandstorm, when the dune brink experienced an advance migration rate of 1.75m in 24h. Sand transport rates of 25.5-36.5m3 m-1 month-1, 22.52m3 m-1 day-1 and 0.93m3 m-1 h-1 were measured for the medium term, short term and very short term, respectively. These values were compared to the theoretical sand transport rate for Valdevaqueros dune, based on the classic Bagnold equation as well other more recent formulae, to obtain a ratio between the real and the theoretical rates for each study period. These results together with the sand drift potential (up to 10,000 vector units) demonstrate that Valdevaqueros (Tarifa) is a dunefield with one of the highest sand transport capacities in Europe.
KW - DGPS levellings
KW - Dune mobility
KW - EOF
KW - Profile changes
KW - Sand drift potential
KW - Transport rates
UR - http://www.scopus.com/inward/record.url?scp=79953788903&partnerID=8YFLogxK
U2 - 10.1016/j.geomorph.2011.01.009
DO - 10.1016/j.geomorph.2011.01.009
M3 - Article
AN - SCOPUS:79953788903
SN - 0169-555X
VL - 129
SP - 14
EP - 28
JO - Geomorphology
JF - Geomorphology
IS - 1-2
ER -