Typhoons Driven Morphodynamics of the Wan-Tzu-Liao Sand Barrier (Taïwan)

Abstract

This study focuses on the dynamics of the Wan-Tzu-Liao sand barrier when it is struck by one typhoon, a group of typhoons or the whole season of typhoons and monsoon. In the framework of the KUN-SHEN project, 7 months of monitoring (2011)(2012) provided 20 topobathymetric surveys (within a 200 m long segment of the barrier from the subtidal zone to the back-barrier) and acquisitions of offshore, nearshore and shallow water hydrodynamics including velocity profiling, free surface measurement and absolute pressure. Offshore waves were extracted at Cigu buoy (18 m of water depth). Nearshore waves were acquired from the current profiler deployed 400 m off the coast in 4 m of water depth and water level on the subaerial beach were acquired from two pressure sensors deployed in the lower part of the subtidal zone and the dune crest. Morphologic changes of the emerged beach were monitored using D-GPS each week during winter monsoon season and just before and after each event during summer typhoons season. Amongst the eight studied typhoons, TALIM is the most energetic event observed. Offshore wave height reached H s = 10.34 m (T p = 14.6 s) at Cigu buoy and H s = 2.3 m (T p = 13.4 s) at the profiler. Surface waves dynamics throughout surf and swash zones are progressively dominated by infragravity motions. A part of the dune is surged at the storm apex. Morphological changes include 6.7 m of dunefoot retreat and a sand transfer from a dune breach to wash-over deposits in the lagoon. More surprisingly, the foreshore was nourished (2261 m

Realistic Simulation of Instantaneous Nearshore Water Levels During Typhoons

“…The south-western coast of Taiwan displays a single well-expressed lagoonal system which is regularly exposed to extreme meteoroligical events. Ours study focuces on the Wan-Tzu-Liao sand barrier which pro- Figure 2: Wind/wave conditions at the CIGU buoy during the simulated period (Campmas et al, 2014).…”

Cross‐shore distributions of peracarid crustaceans after changes in beach morphology: The importance of suction as a key geoenvironmental variable

“…Events, such as storms, can induce physical disturbances that may cause destabilization and subsequent mobilization of sediments, and consequently morphological changes in shallow coastal, estuarine and marine environment (Aubrey, 1983;Campmas et al, 2014;Otvos, 2004;Qi, Cai, Lei, Cao, & Shi, 2010;Switzer & Jones, 2008). Such events may also have strong influences on species richness, abundance, composition and zonation (Alves & Pezzuto, 2009;Dobbs & Vozarik, 1983;Filho & Lana, 2013;Gallucci & Netto, 2004;Harris, Nel, Smale, & Schoeman, 2011;Posey, Lindberg, Alphin, & Vose, 1996;Rees, Nicholaidou, & Laskaridou, 1977;Yeo & Risk, 1979).…”