日本南部黑潮与黑潮延伸体路径状态关联性的定量分析

日本南部黑潮存在多种路径模态:近岸非大弯曲路径、离岸非大弯曲路径和大弯曲路径。黑潮延伸体的路径存在两种典型模态:收缩态和伸展态。从地理位置看, 日本南部黑潮和黑潮延伸体是相邻的, 但它们的路径状态是否存在关联一直存在争议。本文基于卫星观测的海表高度资料和长期的海洋高分辨率再分析资料, 对日本南部黑潮和黑潮延伸体路径状态之间的关联性进行定量分析, 结果表明:日本南部黑潮和黑潮延伸体的路径状态存在一定的关联。当日本南部黑潮处于近岸非大弯曲和大弯曲路径时, 黑潮延伸体主要处于伸展态; 当日本南部黑潮处于离岸非大弯曲时, 黑潮延伸体处于伸展态和收缩态的比例相当。进一步分析表明, 黑潮流轴处于伊豆海脊的位置部分决定了上述关系, 可能存在其他因素调制了两者的关联性。

Quantitative analysis of the relationship between the path states of the Kuroshio south of Japan and the Kuroshio Extension

The Kuroshio south of Japan exhibits various path states: a nearshore non-large mender path, an offshore non-large mender path, and a large mender path. In addition, the Kuroshio Extension (KE) exhibits a typical bimodality: elongation and contraction states. Although the Kuroshio south of Japan and KE have adjacent geographical positions, the relationship between their path states remains debatable. In this paper, this relationship is quantitatively analyzed based on the satellite sea surface height data and long-term high-resolution reanalysis data of the ocean. The results indicate that the path states of the Kuroshio south of Japan and KE are correlated. When Kuroshio south of Japan is in the nearshore non-large mender and large mender paths, KE is mainly in the elongation state. When the Kuroshio south of Japan is in an offshore non-large mender path, KE has a similar probability of being in the elongation and contraction states. Further analysis implies that the location of the Kuroshio current axis above the Izu Ridge partly determines the abovementioned relationship, and other factors may modulate this correlation.