Spatio-temporal variability of currents over a mobile dune field in the Dover Strait

Autor: Déborah Idier, Dominique Astruc, Thierry Garlan
Přispěvatelé: Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut de mécanique des fluides de Toulouse (IMFT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, SHOM, IMFT
Rok vydání: 2011
Předmět:
Zdroj: Continental Shelf Research
Continental Shelf Research, Elsevier, 2011, 31 (19-20), pp.10.1016/j.csr.2011.09.006. ⟨10.1016/j.csr.2011.09.006⟩
ISSN: 0278-4343
1873-6955
DOI: 10.1016/j.csr.2011.09.006
Popis: International audience; A one month field campaign featuring two spring-neap tide cycles and three strong storms has been performed in a mobile dune area located in the central part of the Dover Strait. These dunes are known to move in a complex manner as their migration direction varies in space and time (Le Bot and co-workers, 2000, 2001, 2004). In order to gain some insights into the dune motion processes we present an analysis of the spatio-temporal variability of currents in the area emphasizing the relative influence of tides and storms. A total of eight different hydro-meteorological regimes have been distinguished during the experiment duration. The analysis of the currents measurements at five locations in the area shows that the eight hydro-meteorological regimes induce very different current responses at the bottom. The residual tidal currents exhibit a significant spatial variability both in direction and in intensity. A numerical model of tidal currents over the Dover Strait confirms the strong spatio-temporal variability of the residual tidal currents featuring three singular points. Amongst them, a saddle point is located just south of the I-dune at the convergence of opposite direction residual tidal currents. The wind-induced currents are almost uniform in space, their intensity and direction however strongly depends on the wind regime and thus on time. The mean total current feature a spatial pattern which can be tidal or wind-induced currents dominated, or either in balance, depending on the regime considered. At the PERMOD campaign time scale, the total current is dominated by the residual tidal current. These results proved to give valuable insights to explain the complex dynamics of dune motion observed in this area by Le Bot and co-workers (2000, 2001, 2004) at short and long time scales.
Databáze: OpenAIRE
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