A case study of continental shelf waves in the northwestern South China Sea induced by winter storms in 2021

• Published in: Acta oceanologica Sinica 2024, Vol.43 (1), p.59-69
• Main Authors: Li, Junyi, Zhou, Chen, Li, Min, Zheng, Quanan, Li, Mingming, Xie, Lingling
• Format: Article
• Language: English
• Subjects: Case studies; Climatology; Coasts; Continental shelves; Cruises; Current velocity; Earth and Environmental Science; Earth Sciences; Ecology; Engineering Fluid Dynamics; Environmental Chemistry; Gauges; Laboratories; Marine & Freshwater Sciences; Mooring; Mooring systems; Natural resources; Oceanography; Phase velocity; Propagation; Sea level; Sea level changes; Sea level fluctuations; Sea surface; Shelf waves; Storms; Surface wind; Topography; Typhoons; Wave-current interaction; Wind; Wind data; Winter; Winter storms
• ISSN: 0253-505X; 1869-1099
• DOI: 10.1007/s13131-023-2150-5

This study aims to investigate characteristics of continental shelf wave (CSW) on the northwestern continental shelf of the South China Sea (SCS) induced by winter storms in 2021. Mooring and cruise observations, tidal gauge data at stations Hong Kong, Zhapo and Qinglan and sea surface wind data from January 1 to February 28, 2021 are used to examine the relationship between along-shelf wind and sea level fluctuation. Two events of CSWs driven by the along-shelf sea surface wind are detected from wavelet spectra of tidal gauge data. The signals are triply peaked at periods of 56 h, 94 h and 180 h, propagating along the coast with phase speed ranging from 6.9 m/s to 18.9 m/s. The dispersion relation shows their property of the Kelvin mode of CSW. We develop a simple method to estimate amplitude of sea surface fluctuation by along-shelf wind. The results are comparable with the observation data, suggesting it is effective. The mode 2 CSWs fits very well with the mooring current velocity data. The results from rare current help to understand wave-current interaction in the northwestern SCS.