Author(s): Zhanxiang Peng; Wenyun Guo; Hongsheng Zhang

Linked Author(s):

Keywords: Internal solitary wave; Northern South China Sea; Spatio-temporal distribution; Crest line; Wave direction

Abstract: Internal solitary waves are a special type of oceanic internal waves characterized by short periods, small wavelengths, and strong nonlinearity. They occur quite frequently, particularly in the northern part of the South China Sea. The suddenness and extremely strong destructiveness of internal solitary waves can often pose serious threats to marine constructions and activities. Based on 3085 optical images obtained from the Terra and Aqua satellites of MODIS, which are publicly offered by Zhang et al, the spatial and temporal distribution characteristics of internal solitary waves in the northern part of the South China Sea are analyzed. The results show that internal solitary waves in the northern part of the South China Sea are almost evenly distributed throughout the region in space, with the most-dense distribution in the shallow waters near the Dongsha Islands, followed by the western side of the Luzon Strait deep sea area and the eastern region of Hainan Island. At the same time, due to the influence of the thermocline, the generation of Internal solitary waves shows an obvious seasonal pattern in time. The shallower thermocline in summer is conducive to the generation of internal solitary waves, and their frequency is the most frequent, reaching the highest in July, followed by June, and reaching the lowest in December and January. The length of the wave crest lines of internal solitary waves is mainly concentrated in the range of 0-50 km, and there are also wave crest lines above 50-200 km, and the number of corresponding internal solitary waves will decrease sharply with the increase of wave crest line length. Similar to the distribution of time, the scale of the wave crest and the number of corresponding internal solitary waves also show seasonal changes, with a decrease order of summer, spring, autumn and winter. The wave direction is mainly westward and northwestward, accounting for about 80%, while internal solitary waves with a main direction of eastward are almost nonexistent.

DOI: https://doi.org/10.64697/IAHR-APD2024_P262

Year: 2024