The focus of this study was the temporal and spatial variations of extreme significant wave heights and nearshore return-period wave heights in the South China Sea, based on the wave model and European Reanalysis-Interim data from 1979–2016. Measured buoy data were available from near Yongxing Island for comparison with the reanalysis data during the passage of typhoons. Annual maximum significant wave heights showed a statistically significant increasing trend over most of the South China Sea, whereas statistically insignificant decreasing or increasing trends were observed for seasonal maximum significant wave heights associated with the different characteristics of the typhoon events. Nonstationary generalized extreme value analysis was used to investigate the influence of nearshore extreme significant wave heights derived from the Simulating Waves Nearshore model at four offshore locations in the South China Sea. The fastest increase of 100-year return significant wave heights was found to be 0.0033 m yr−1 in the western South China Sea. The results show that, in recent decades, no significant variation trends can be found in return-period wave heights at nearshore of South China Sea, which may be related to tracks of intense typhoons in the region.

中文翻译：

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南海极端显着波高变化趋势研究

本研究的重点是基于波浪模型和 1979-2016 年欧洲再分析中期数据，南海极端显着波高和近岸回归波高的时空变化。永兴岛附近的实测浮标数据可用于与台风经过期间的再分析数据进行比较。南海大部分地区的年最大显着波高呈现出统计上显着的增加趋势，而与台风事件的不同特征相关的季节性最大显着波高则观察到统计上不显着的减少或增加趋势。采用非平稳广义极值分析，研究了模拟波浪近岸模型在南海四个近海位置得到的近岸极显着波高的影响。发现南海西部的 100 年回归显着波高增长最快的是 0.0033 m yr-1。结果表明，近几十年来，南海近岸回归波高未发现显着变化趋势，这可能与该地区强台风的路径有关。