Long-term variation of the wave power density in the South China Sea over the past 28 years

Based on 28 years of hindcast data, this paper describes in detail the long-term variation trend of wave power density in the South China Sea. WAVEWATCH-III (WW3), the third generation wave computing model, which plays an important role in wave prediction. WW3 was used for inverse calculation of wave parameters, with spatial resolution of $0.25^{\circ }\times 0.25^{\circ }$ and time resolution of 6h. The validity of the data was verified by three typhoon processes and the significant wave height data of the satellite altimeter in 2010. According to 28-year(1990–2017) hindcast data set, the author respectively mapped the South China Sea mean monthly, seasonal, annual wave power density (WPD) and the change trend diagram, including the long-term trend of WPD Mann-Kendall (MK) test, come the following conclusions: (1) Influencing the area WPD change trend of the dominant increasing season is winter (DJF), in which season average growth of WPD is about 1kW/m, and the largest waters is closed to 3kW/m. (2)The dominant growing month for WPD is in December, by compared with the before and next month in the largest growing sea area, it shows an increase and decrease trend of 10kW/m and 20kW/m respectively. (3)MK test results indicate that the long-term change of WPD keep on an increasing trend, but it is not significant, among which WPD had an increased mutation in 2000. (4)The dominant sea area is around Luzon Strait-Taiwan Strait- D.S Islands (116°E, 21°N). The average growth of WPD among these area in 28 years are about 0.15–0.25(kW/m)/yr.