黑潮季节变化对次级海洋环流的影响

Influences of the Kuroshio seasonal variation on the oceanic sub circulation

中文关键词:  黑潮，热源，两层半海洋模式， 次级环流

英文关键词:Kuroshio, Heat source, 2.5-layer oceanic model, Sub-circulation

中文摘要:

      黑潮是全球大洋中和大气之间进行热量交换最多的海域之一，它所携带的热量对局地的海-气相互作用具有重要影响。20世纪50—60年代，中国学者就发现冬季黑潮流域的海表温度与中国长江流域汛期降水存在着密切联系。文中利用一个两层半海洋模式主要从动力学角度探讨黑潮流域热源的季节变化对次级海洋环流的影响。结果表明，在黑潮流域冬暖夏冷的外源强迫下，温跃层的海温异常峰值比热源的峰值滞后一个季节，春季的海温异常达到最大。混合层年平均海温异常为正，从冬季到夏季均偏高，春季最大，仅秋季为负异常，这与观测资料一致。混合层与温跃层的春季海温异常的量值大体相当，在其他季节混合层的海温异常均高于温跃层。从冬季到夏季，温跃层和混合层的次级环流呈现从气旋型环流到反气旋型环流的转变，这样的异常环流在夏季有利于向中国东部附近海域输送热量。

英文摘要:

      The Kuroshio valley is one of the most active air sea heat exchange oceanic regions in the global oceans, and the heat carried by it plays an important role in the local air sea interaction. The early studies in 1950-1960s found the relationship between the winter Kuroshio sea surface temperature and the summer precipitation over the Yangtse River valley. A 2.5－layer oceanic model is employed to investigate the influences of the Kuroshio seasonal variation on the oceanic sub circulation from a dynamic view. Under the forcings of the heat source in winter as well as the heat sink in summer, the peak of the thermocline temperature anomaly is in the spring, lagging one season behind that of the heat source. The seasonal peak of the mixed layer temperature anomaly is also in the spring. The anomalies of the mixed layer temperature are positive from the winter to the summer and are negative in the autumn, which is consistent to the results of observational data. The mixed layer temperature anomalies are generally equal to the thermocline temperature anomalies in the spring and are higher than those in the others seasons. The sub circulations of the thermocline and mixed layers present the anticyclones in the winter shifting to the cyclones in the summer. These situations are conductive to the heat transfer to the seas nearby the eastern China in the summer.