基于20a卫星高度计数据的黑潮变异特征

Variability of Kuroshio based on 20-year altimeter data

黑潮作为一支典型的西边界流,其路径变化特征及其相关的物理现象对于渔业和航海有着不可忽视的影响。本文基于改进的特征线方法,利用1992-2012年的高度计绝对动力地形数据提取了整个黑潮流区逐月的黑潮主轴和边界位置,并对沿轴速度、主流宽度、表层水体输运以及路径标准差等黑潮特征量进行了分析研究。结果表明,黑潮整体的沿轴速度在夏秋季较大,最大值可达0.95 m/s,而在冬季的速度较小;黑潮主流宽度在10、11月份达到最大值;黑潮表层水体输运在夏季最大,春秋两季次之,冬季最小。沿黑潮流路分区域对黑潮特征进行分析,结果表明,越往黑潮下游,其沿轴速度、主流宽度和表层水体输运越大,同时沿轴速度和表层水体输运量最大值出现的时间也越晚,黑潮主轴位置相对于其多年平均的偏离程度越大,且随时间波动也越强烈。

Based on 20-year（1991–2012） Absolute Dynamic Topography derived satellite altimetry data, the location of the axis and boundary of the Kuroshio Current are derived using the improved characteristic line method. In addition, the variability of the along-stream velocity, section width, along-stream surface transport, and path standard deviation of the Kuroshio Current are studied. The results show that the along-stream velocity of the Kuroshio increases from a minimum value during winter to a maximum of 0.95 m/s in summer and autumn, and a larger mainstream width occurs in October and November. The mean surface along-stream transport has a maximum value in summer; there is reduced transport in spring and autumn, and it is at a minimum in winter. Based on a study of different regions along the current, it was found that along-stream velocity, section width, and along-stream surface transport increase along the current, while the time when the maximum value of the along-stream velocity and surface transport occur is late. The location of the axis of the Kuroshio Current departs from the annual mean path further along the current, and fluctuations become stronger with time.