全球涌浪池分布及年际变化分析

Analysis of Global Swell Pool Distribution and Interannual Variation

随着涌浪引起海表至大气的直接动量和能量输送过程被揭示,针对涌浪的深入研究越来越重要。过去受限于资料,涌浪信息的提取通常采用经验公式和概率统计相结合的方法,难以研究涌浪变化规律。本研究提出从海浪谱中分解涌浪谱,并通过谱能比例的方法确定涌浪事件及其概率,通过处理30年全球高分辨率海浪再分析数据产品中海浪二维方向谱数据,对全球涌浪池分布及年际变化进行了详细分析。研究结果表明,全球涌浪池在赤道、30°S和30°N附近沿纬向成条带分布,北印度洋东侧、赤道太平洋西侧和东侧、赤道大西洋东侧分布着4个典型涌浪池;全球涌浪池分布具有明显的季节变化,表现为夏季涌浪频繁,冬季较少;涌浪池的年际变化具有较为显著的11年周期,与ENSO事件高度相关,北印度洋东侧、赤道太平洋东侧涌浪波高异常与南方涛动指数(SOI,Southern Oscillation Index)指数的相关系数分别为0.43和0.51。本研究填补了以往研究只能对全球涌浪池的气候特征进行分析,而不能对全球涌浪池的年际变化进行分析的空白,可为涌浪和海气相互作用研究提供一定的参考。

As the phenomenon of direct momentum and energy transfer from the sea surface to the atmosphere caused by swell is revealed and confirmed,the further study of swell is becoming more and more important.In previous studies,the research on the variation of swell is limited by the data and the extraction of swell information usually adopts the method of combining empirical formula and probability statistics,which is difficult to study the variation characteristics of swell.In this paper,the swell information is extracted based on the two-dimensional wave spectrum,and define the swell event based on spectral energy ratio.By processing the two-dimensional directional spectrum data in the global high-resolution wave reanalysis data product for 30 years,the global swell pool distribution and interannual variation are analyzed in detail.The results indicate that the global swell pools are mainly distributed in the equatorial ocean,in addition,there are zonally banded areas of swell pools near 30°S and 30°N.Four typical swell pools are distributed on the east side of the North Indian Ocean(NIO),the Western Equatorial Pacific Ocean(WEPO),the Eastern Equatorial Pacific Ocean(EEPO)and the Eastern Equatorial Atlantic Ocean(EEAO).The distribution of global swell pools has obvious seasonal changes,which shows that there are frequent swell events in summer and less in winter.The interannual variation of the swell pool has a significant 11 year variation cycle,which is highly correlated with ENSO events.The correlation coefficients between the swell wave height anomaly in the east side of NIO and WEPO and SOI index are 0.43 and 0.51 respectively.This study fills the gap that only the analysis for the climatic characteristics of global swell pool can be performed,instead of the interannual variation of global swell pool in previous studies,and can provide the references for the application of swell and the study of air sea interaction.