Shoreline Response to a Sequence of Typhoon and Monsoon Events

Abstract

Shoreline continuously adapts to changing multi-scale wave forcing. This study investigates the shoreline evolution of tropical beaches exposed to monsoon events and storms with a case study in Vietnam, facing the South China Sea, over the particularly active 2013-2014 season, including the Cat-5 Haiyan typhoon. Our continuous video observations show for the first time that long-lasting monsoon events have more persistent impact (longer beach recovery phase) than typhoons. Using a shoreline equilibrium model, we estimate that the seasonal shoreline behavior is driven by the envelope of intra-seasonal events rather than monthly-averaged waves. Finally, the study suggests that the interplay between intra-seasonal event intensity and duration on the one hand and recovery conditions on the other might be of key significance. Their evolution in a variable or changing climate should be considered.

Contributions to Coastal Flooding Events in Southeast of Vietnam and their link with Global Mean Sea Level Rise

“…The relatively low temporal resolution of altimetry satellites limits the capacity of this remote sensing method to capture this type of short-term sea level change. Nevertheless, along the Nha Trang coast, winter monsoons characterized by long-lasting energetic waves and positive NTR are the main mechanism responsible for shoreline retreat and flooding events [18]. Thus, underestimating the Typhoon contributions is unlikely to significantly affect the present findings.…”

“…The wave climate and sea level at Nha Trang is strongly influenced by two monsoon seasons-the winter and summer monsoons. The winter monsoon is characterized by strong winds (between 8-12 m/s), energetic waves and positive non-tidal residual (NTR), typically occurring during the wet season (from October to March), while the summer monsoon is characterized by relatively mild wind and wave regimes and small to negative NTR [18,19]. In addition to the monsoon seasons, tropical cyclones, also known as Typhoons, can produce very energetic waves and extreme sea levels in the area, resulting in infrequent but significant coastal flooding events [20].…”

Why and How Do We Study Sediment Transport? Focus on Coastal Zones and Ongoing Methods

“…Scientific issues are common, and digital communication has allowed researchers to multiply worldwide collaborations, disrupting the production of knowledge. This special issue thus reflects the ongoing international cooperation between northern and southern countries on sensitive topics of common interest, thanks to the support of scientific research organizations such as the Institute of Research for Development in France, or through dedicated projects [57,351,[353][354][355][356].…”

“…This special issue also contains works whose purpose is to quantify volumes of sediments transiting between morphological domains (estuary, beaches, spit, shelf) or which are redistributed between adjacent compartments, and which shape the coast at seasonal and interannual scales. Several illustrations concern sandy coasts in Senegal [57], Benin [351], Australia [352] and Vietnam [353], and one illustration concerns a muddy environment along the Mekong Delta [354]. Volumes of transported sediments serve as a basis for studying processes and for sensitivity analysis of shoreline changes under different forcing.…”

“…Almar et al [353] investigated the shoreline response to a sequence of typhoon and monsoon events along the sandy beach of Nha Trang in Vietnam during a particularly active 2013-2014 season which encompassed the category 5 Haiyan typhoon. From continuous video monitoring, they show that long-lasting monsoon events have more persistent impact (longer beach recovery phase) than the typhoon.…”