Publications des scientifiques de l'IRD

Thanh T. M., Tanaka H., Mitobe Y., Viet N. T., Almar Rafaël. (2018). Seasonal variation of morphology and sediment movement on Nha Trang Coast, Vietnam. Journal of Coastal Research, (81 No Spécial), p. 22-31. ISSN 0749-0208.

Titre du document
Seasonal variation of morphology and sediment movement on Nha Trang Coast, Vietnam
Année de publication
2018
Type de document
Article référencé dans le Web of Science WOS:000457252000005
Auteurs
Thanh T. M., Tanaka H., Mitobe Y., Viet N. T., Almar Rafaël
Source
Journal of Coastal Research, 2018, (81 No Spécial), p. 22-31 ISSN 0749-0208
The Nha Trang beach, an embayed sandy beach located in the southeast of Vietnam, is a tropical touristic coastal environment that is being threat by persistent shoreline retreat. In order to investigate the processes underlying this erosive pattern, 1.5-years of video imagery, obtained from a local video system, was analyzed. Video products such as shoreline position and surf zone width (extracted from time-averaged images) were used to identify patterns of shoreline variability (using empirical orthogonal function - EOF) and investigate the link between the seasonal variations in the wave forcing and longshore sediment transport. Results indicate that shoreline retreat occurs essentially during the winter season, when energetic northeast monsoon waves dominate. The recovery phase (shoreline advance) was found to occur during the summer season, when milder south/southeast wind waves dominate. Shoreline variability was further investigated using EOF analysis and results show that the first mode, which explains 89% of the observed variance, corresponds to the seasonal longshore shoreline variations. This EOF mode was found to strongly related to the winter and summer monsoon seasons, thus reinforcing the role that seasonal changes in the wave climate play on the shoreline variations. Finally, the net of longshore sediment transport in Nha Trang beach was investigated using seasonal and monthly depth of closure (D-c) information, rather than a single fixed value of this parameter. The results highlight that the use of monthly or seasonal D-c values allow to capture the seasonal variations in the wave climate, thus providing more realistic patterns of sediment transport in this coastal area.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Limnologie physique / Océanographie physique [032] ; Géologie et formations superficielles [064]
Description Géographique
VIET NAM ; NHA TRANG
Localisation
Fonds IRD [F B010075138]
Identifiant IRD
fdi:010075138
Contact