The spatio-temporal variations of the significant wave height (SWH) in the Western North Pacific and South China Sea (WNP-SCS) region, as well as their driving mechanisms, are investigated based on the long-term (1981–2014) simulation by a coupled ocean–atmosphere model and a W AVEW ATCH III model. The Empirical Orthogonal Function modes of SWH anomalies show different patterns in the cold and warm seasons. In winter, the first mode (explaining 40.63% of the variance) shows a monopole pattern with large loadings lying in SCS and the WNP to the east of the Philippine Islands, which is primarily associated with the El Ni?o-Southern Oscillation (ENSO) on inter-annual time scales. The second mode (explaining 19.62% of the variance) shows a dipole pattern with negative loadings in the northeastern SCS and positive loadings to the east of Japan, which is prominently connected with the intensity variation and longitudinal shift of Aleutian Low on decadal time scales. In summer, the first leading mode (explaining 73.47% of the variance) presents large loadings located mainly in the WNP region between 10° N and 30° N and secondarily in the central SCS, which is associated with the ENSO-affected tropical cyclone activities and South China Sea summer monsoon, respectively.

北太平洋西部和南海地区有效波高的年际变化

中文摘要：基于海洋-大气耦合模式和WAVEWATCH III模式的长期（1981–2014）模拟，研究了西北太平洋和南海(WNP-SCS)有效波高（SWH)的时空变化及其驱动机制。SWH的经验正交函数模态在寒季和暖季表现出不同的模式。在冬季，第一模态(方差贡献率为40.63%)表现为南海和菲律宾群岛以东的西太平洋地区的有较大载荷的单极模态，这主要与年际时间尺度上的厄尔尼诺南方涛动(ENSO)有关。第二种模态(方差贡献率为19.62%)表现为南海东北部负载荷、日本东部正载荷的偶极模态，这与阿留申低压在年代际时间尺度上的强度变化和纵向移动密切相关。在夏季，第一模态(方差贡献率为73.47%)主要出现在10°N ~ 30°N之间的西北太平洋区域，其次出现在南海中部，这分别与ENSO影响的热带气旋活动和南海夏季风有关。