Influence des tempêtes sur la mobilité des dunes tidales dans le détroit du Pas-de-Calais

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• 作者：LE BOT ; Sophie ; TRENTESAUX ; Alain ; GARLAN ; Thierry ; BERNE ; Serge ; CHAMLEY ; Hervé
• 关键词：dé ; troit du Pas-de-Calais ; dynamique sé ; dimentaire ; dunes tidales ; tempê ; tes
• 刊名：Oceanologica Acta
• 出版年：2000
• 出版时间：April 4, 2000
• 年：2000
• 卷：23
• 期：2
• 页码：129-141
• 全文大小：602 K

文摘

Influence of storms on tidal dune mobility in the Strait of Dover. The present paper deals with dune dynamics in a zone of the Strait of Dover located in the sea lane running into the North Sea. The dunes, widespread in this 35-m depth area, are mobile sedimentary structures (up to 40 m·yr⁻¹) that culminate at a maximum of 22 m depth and endanger navigation as well as submarine man-made structures (cables, pipelines). Single- and multibeam bathymetric data, coupled with seismic data, allow us to follow dune displacements over different time scales. A net bedload parting zone has been displayed and divides the area into two parts, SE and NW. However, according to the considered time-scale, dune movements present variations in intensity and direction. Over a long-term period (decades), sedimentary dynamics fit the regional scheme of the residual tidal currents that induce transport toward the SW and the NE in the respective SE and NW parts of the studied area. Over a medium-term period (several years), meteorological data show that a high frequency of storm winds alters the residual sand transport characteristics by strengthening, slowing or reversing the effect of the tidal currents and can lead to the reversal of dune asymetry. © 2000 Ifremer/CNRS/IRD/Éditions scientifiques et médicales Elsevier SASStrait of Dover / sedimentary dynamics / tidal dunes / storms