@article{fdi:010076543,
  title = {{V}ideo sensing of nearshore bathymetry evolution with error estimate},
  author = {{T}huan, {D}. {H}. and {A}lmar, {R}afa{\¨e}l and {M}archesiello, {P}atrick and {V}iet, {N}. {T}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}lthough coastal morphology results essentially from underwater sediment transports, the evolution of underwater beach profiles along the diverse coastlines of the world is still poorly documented. {B}athymetry inversion from shore-based video cameras set forth a more systematic evaluation and is becoming more commonly used. {H}owever, there are limitations to this profiling method that are insufficiently assessed, undermining confidence in operational applications. {I}n this paper, we investigate the daily evolution of a low tide terrace ({LTT}) in {N}ha {T}rang beach, {V}ietnam, under strong seasonal forcing: from weak wind waves during summer monsoon to moderate waves during winter monsoon. {A} new error estimation for depth inversion is presented based on tidal evaluation. {T}he method compares video-based estimate and direct measurement of tidal amplitudes to provide a quality criterion. {I}t reveals three types of errors, the main one being a deep water error associated with physical limits-loss of celerity-bathymetry relationship in deep water. {T}his error is dependent on wave period and thus has a strong seasonal pattern in {V}ietnam. {I}t is generally detrimental to depth inversion where wind waves are dominant (in summer here). {O}n the contrary, the second error type is larger for larger waves and is located at breakpoint, altering wave detection. {T}he last error type is due to nonlinear effects and wave setup in shallow water. {A}fter removing the faulty data, we finally present the first reliable three-year time-series of a beach profile in {N}ha {T}rang, {V}ietnam. {A} main result is the overall stability demonstrated for the {LTT} beach, with rapid exchange of sediment between the terrace and the upper beach during typhoons, monsoon events or seasonal cycles. {T}hese tropical environments may provide faster beach recovery compared with mid-latitude configurations.},
  keywords = {depth inversion ; low tide terrace ; morphological evolution ; error ; quantification ; wind waves ; {VIET} {NAM} ; {NHA} {TRANG} {BAIE} ; {CHINE} {MER}},
  booktitle = {},
  journal = {{J}ournal of {M}arine {S}cience and {E}ngineering},
  volume = {7},
  numero = {7},
  pages = {art. 233 [17 p.]},
  year = {2019},
  DOI = {10.3390/jmse7070233},
  URL = {https://www.documentation.ird.fr/hor/fdi:010076543},
}