@article{fdi:010037825,
  title = {{T}rade-wind waves and mud dynamics on the {F}rench {G}uiana coast, {S}outh {A}merica : {I}nput from {ERA}-40 wave data and field investigations},
  author = {{G}ratiot, {N}icolas and {G}ardel, {A}. and {A}nthony, {E}. {J}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {S}outh {A}merican coast between {B}razil and {V}enezuela is affected by longshore migrating mud banks derived from the fine-grained {A}mazon sediment discharge. {O}nshore mud migration prevails over shallow 'bank' areas alternating alongshore with deeper 'inter-bank' areas. {T}he transport on the inner shelf, and attachment to the shoreline, of this migrating mud has been attributed mainly to wind waves. {H}owever, the lack of in situ data on waves hampers understanding of the relationship between waves and mud dynamics. {A} 44-yr record (1960-2004) of the {ERA}-40 wave dataset generated by the {E}uropean {C}entre for {M}edium-{R}ange {W}eather {F}orecasts ({ECMWF}) was used, in conjunction with field investigations in {F}rench {G}uiana, to define both event-scale and longer-term patterns of mud mobilisation induced by waves. {T}he ratio {H}-0(3)/{T}-2, combining wave height {H} and period {T}, and the angle of wave incidence alpha, were singled out as the most relevant parameters for describing wave forcing. {T}ypical 'bank' and 'inter-bank' profiles and corresponding mud densities, and a 3-month record of changes in the thickness of the fluid mud layer in an estuarine navigation channel were monitored by echo-sounding from {O}ctober 2002 to {J}anuary 2003. {A}n 80-day record of bed-level changes in the intertidal zone was obtained from {A}ugust to {N}ovember 2004 using a pressure transducer. {T}he results on the wave regime of {F}rench {G}uiana confirm a distinctly seasonal pattern, and highlight an increase in {H}-0(3)/{T}-2 over the 44-yr period related to an increase in trade-wind velocities determined from corresponding trends in {A}tlantic wind pseudo-stress off the {S}outh {A}merican coast. {W}ave forcing over bank areas leads to the liquefaction of a 1-3 m-thick layer of mud that is transported onshore (and alongshore by the longshore component of wave energy). {T}he episodic nature of high wave energy events generally results in the formation of mud bar features from the shoreward mobilisation of gel-like fluid mud. {T}he effect of waves on mud is particularly marked following long periods of low energy, and especially at the onset of the high wave energy season ({O}ctober to {M}ay), when even moderate wave energy events can lead to significant mobilisation of mud. {S}ignificant phases of increased wave energy are attended by higher long-term (annual) rates of longshore mud bank migration but the correlation is rather poor between the wave forcing parameter {H}-0(3)/{T}-2 and migration rates because stronger wave forcing is generally associated with low angles of wave incidence. {T}his suggests a complementary role of other hydrodynamic mechanisms, such as geostrophic and tidal currents, in longshore mud bank migration.},
  keywords = {trade wind waves ; {ERA} 40 wave dataset ; mud banks ; mangroves ; {F}rench {G}uiana},
  booktitle = {},
  journal = {{M}arine {G}eology},
  volume = {236},
  numero = {1-2},
  pages = {15--26},
  ISSN = {0025-3227},
  year = {2007},
  DOI = {10.1016/j.margeo.2006.09.013},
  URL = {https://www.documentation.ird.fr/hor/fdi:010037825},
}