基于AVISO卫星高度计资料的黑潮表层流轴时空变化特征分析

Analysis of Spatiotemporal Variation Characteristics of the Kuroshio Surface Axis Based on AVISO Satellite Altimeter Data

摘要:

黑潮是著名的太平洋西边界流，是东中国海环流系统的主动脉。我国东海和黄、渤海的水文状况，基本上受黑潮及其分支所制约，因此，对黑潮的研究受到国内外学者的广泛关注。针对 AVISO 高度计地转流资料，采用改进的特征线法和最大梯度法，实现对黑潮表层流轴的自动化探测。利用经验模分解方法对黑潮流轴的离岸距离序列进行了分解，并利用自组织映射方法对黑潮流轴进行了分类。结果表明，黑潮流轴在本州岛南部和九州岛南部海域摆动幅度较大，在四国岛南部海域摆动幅度较小。在九州岛南部海域，黑潮流轴在所研究时间段内有超过一半时间呈近岸平直特征，而“大弯曲”状态占比约 35%。

Abstract:

The Kuroshio is a famous western boundary current of the Pacific Ocean and the main artery of the circulation system of the East China Sea. The hydrological conditions of the East China Sea，the Yellow Sea，and the Bohai Sea in China are basically constrained by the Kuroshio and its branches. Therefore，research on the Kuroshio has received widespread attention from scholars. Based on the AVISO altimeter geostrophic current data，an improved feature line method and maximum gradient method are used to achieve automated detection of the Kuroshio surface current axis. The empirical mode decomposition method is used to decompose the offshore distance sequence of the Kuroshio Current axis，and the self-organizing mapping method is used to classify the Kuroshio Current axis. The results indicate that the Kuroshio Current axis oscillates significantly in the southern waters of Honshu Island and Kyushu Island，while the oscillation amplitude is relatively small in the southern waters of Shikoku Island. In the regions on the south of the Kyushu Island，the Kuroshio axis mainly presents nearshore and straight patterns for more than half of the studied time period，and the “large meandering” state accounts for approximately 35%.