A simple early warning method for large internal solitary waves in the northern South China Sea. (December 2016)

• Record Type: Journal Article
• Authors: Li, Youkai; Wang, Caixia; Liang, Chujin; Li, Junde; Liu, Weian
• Is Part Of: Applied ocean research. Volume 61(2017:Jun.)
• Page Start: 167
• Page End: 174
• Publication Date: 2016-12
• Subjects: Internal solitary wave -- Northern South China Sea -- Propagation speed -- Early warning -- Morison's equation -- Force and torque; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2016.11.002
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: The nonlinear propagation speeds of large internal solitary waves are obtained. The water stratification is derived from WOA13 data instead of CTD casts. The accuracy of early warning is verified by two synchronous mooring buoys. The force and torque on a platform are calculated by adjusting Morison's equation. Abstract: Internal solitary waves (ISWs) are ubiquitous phenomena in many coastal oceans, especially the northern South China Sea (SCS). They can pose a serious threat to the deep-water drilling platforms and other ocean engineering structures. In this paper, we describe a simple and economical early warning method by estimating ISW propagation speeds using the measurements by a single acoustic Doppler current profiler (ADCP). This method is based on the Korteweg-de Vries (KdV) equation. As an example, a set of observational data collected by mooring buoys at the Liwan block (19–20°N, 115–116°E) of the northern SCS are used to calculate the propagation speeds and directions of measured ISWs. The accuracy of estimated ISW propagation speeds is also tested by tracking the signals of ISWs using two ADCP moorings and it is found that the prediction deviation is less than 10%. The force and torque exerted by an ISW on a semisubmersible drilling platform are also estimated according to Morison's equation and other empirical formulas, which can provide a reference for safety controls on offshore platforms.