近赤道太平洋涡旋的统计特征及分布规律

Statistical Characteristics and Distribution Patterns of Equatorial Pacific Eddies

  • 摘要: 以往关于涡旋特征的统计分析研究主要集中在赤道外海域或者笼统地包含在全球涡旋统计分析之中,缺乏针对近赤道海域中尺度涡旋的结构特征和统计分析。近赤道太平洋地处影响全球气候变化的关键海域,该海域的涡动热通量对ENSO事件有重要影响,因此对于近赤道太平洋涡旋的研究非常重要。本文使用基于卫星高度计的海洋涡旋识别与追踪数据集,对近赤道太平洋1993—2020年涡旋的时空分布与生消规律进行了研究,给出了该海域涡旋半径、振幅、寿命、涡动能、西向移动速度和距离的分布直方图,同时分析了涡旋的传播规律、统计特征的经向分布及其季节和年际变化情况。结果表明,近赤道太平洋涡旋的净生成数量大于0,在该海域生成的涡旋普遍有向极运动的趋势;研究海域寿命不短于4周的涡旋可产生约13 Sv的西向水体输运和约1 Sv的向极水体输运;涡动能在赤道以北的纬向平均值最大,向南北两侧逐渐减小;涡旋半径和振幅与Niño 3.4指数存在较强的负相关,而日均涡旋识别数量与Niño 3.4指数有较强的正相关。

     

    Abstract: Previous statistical analyses of eddy characteristics have focused primarily on extratropical oceans or on global integrated properties, with a notable lack of research on the features and statistics of near-equatorial mesoscale eddies. The equatorial Pacific is a region of global climate importance, where eddy-induced heat fluxes play an important role in ENSO events. Therefore, the study of near-equatorial eddies is of great importance to ocean circulation and climate. This study utilizes a dataset of satellite altimetry-based eddy identification and tracking analysis to investigate the spatiotemporal distribution and generation-to-demise patterns of eddies in the near-equatorial Pacific from 1993 to 2020. Statistical analysis reveals the equatorial Pacific as a net eddy source region, with eddies moving predominant westward and poleward. Eddies with lifespan of at least 4 weeks generate a westward net transport of about 13 Sv and a poleward net transport of about 1 Sv. The zonal-averaged eddy kinetic energy shows a peak to the north of the equator, decreasing nearly symmetrically toward higher latitudes. Significant variability associated with ENSO is observed, with eddy size and amplitude correlating negatively, while eddy occurrence frequency correlating positively, with the Niño 3.4 index. These results help understand the role of eddies in climate variability.

     

/

返回文章
返回