FN Archimer Export Format
PT J
TI Fortnightly tidal asymmetry inversions and perspectives on sediment dynamics in a macrotidal estuary (Charente, France)
BT 
AF TOUBLANC, Florence
   BRENON, Isabelle
   COULOMBIER, T.
   LE MOINE, Olivier
AS 1:1;2:1;3:1;4:2;
FF 1:;2:;3:;4:PDG-ODE-LITTORAL-LERPC;
C1 UMR 7266 LIENSs CNRS-University of La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle, France
   IFREMER-LERPC, Center of La Tremblade, Ronce-les-Bains, 17390 La Tremblade, France
C2 UNIV LA ROCHELLE, FRANCE
   IFREMER, FRANCE
SI LA TREMBLADE
SE PDG-ODE-LITTORAL-LERPC
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
IF 2.011
TC 28
UR https://archimer.ifremer.fr/doc/00245/35650/40645.pdf
LA English
DT Article
DE ;Estuary;Tidal asymmetry;Duration asymmetry;Ebb/flood dominance;Morphology;External/internal overtides;Sediment transport
AB Tidal asymmetry is a phenomenon that characterises estuarine hydrodynamics and has a strong impact on sediment dynamics. Extensive research has been dedicated to studying tidal dynamics in semidiurnal macrotidal estuaries, highlighting several general principles. The ratio of flood to ebb peak velocities and differences in ebb and flood durations are often used to characterise the asymmetry encountered in estuaries. In the Charente estuary (French Atlantic coast), water surface elevation data obtained using an ADCP (Acoustic Doppler Current Profiler) and a tide gauge show that the duration asymmetry undergoes inversions during the spring-neap tidal cycle. A two-dimensional hydrodynamics model is used to investigate the connection between spring-neap inversions of the tidal asymmetry and the harmonic composition of the tide. Different constituents (M2, S2, M4 and MS4) are considered at the open boundary. The results show that M4 and MS4 play a key role in the occurrence of these inversions. The influence of the morphology is also discussed and modifications of the bathymetry are performed to evaluate its impact. In the Charente estuary, the existence of both externally and internally generated overtides thus results in a spatially and fortnightly variable tidal asymmetry. The modelled barotropic tidal currents are used to estimate the possible impact on sediment dynamics. The results suggest that asymmetry inversions tend to create sediment accumulation in an intermediate zone between the river mouth and Rochefort, located approximately 20 km upstream.
PY 2015
PD FEB
SO Continental Shelf Research
SN 0278-4343
PU Elsevier
VL 94
UT 000349804200005
BP 42
EP 54
DI 10.1016/j.csr.2014.12.009
ID 35650
ER

EF