东海黑潮与陆架海之间的水交换研究

Study of the water exchange between the Kuroshio and the East China Sea

利用三维海洋环流数值模型(Regional Ocean Model System,ROMS)对东中国海海域黑潮流系系统(东中国海黑潮流系)的季节变化和年际变化进行了模拟和研究,给出了东海黑潮流系穿越东海大陆架200 m等深线的体积通量及其变化规律。研究发现,黑潮的西南段,其主轴位置在春、夏季更加偏东;中间段具有最稳定的流径;而东北段则表现出最大的季节性变化。此外,从月平均结果看,黑潮流系穿越东海大陆架200 m等深线的体积通量,时间上表现为,在夏季减到最小,为0.479 6 Sv(1 Sv≡10~6m^3·s^(-1)),冬季达到最大值,为1.69 Sv;空间上表现为在西南段和中间段较大,而东北段较小。这反映了黑潮水与东中国海大陆架水的水交换区位置,在冬季在向岸方向上离黑潮主轴较远,在夏季离主轴较近。通过对长时间模型结果的时间序列分析,揭示了相对与2000年前,2000年后的黑潮在台湾岛东部水体积通量的季节变化呈现出减弱的趋势。

The seasonal variation and interannual variability of the Kuroshio in the East China Sea during the period of 1991 to 2008 are studied using a three-dimensional Regional Ocean Model System（ROMS）. The volume flux of the Kuroshio across 200 m isobath in the East China Sea continental shelf and its change rule are given. The study finds that the axis position in the southwest section of Kuroshio is more inclined to the east in spring and summer. The flow path in the middle part of the Kuroshio is the most stable, while the seasonal change in the northeast section of the Kuroshio is the greatest.What＇s more, in terms of the monthly average, the volume flux of the Kuroshio across 200 m isobath in the East China Sea continental shelf has a minimum of 0.479 6 Sv（1 Sv≡10^6m3·s-1） in summer and a maximum of 1.69 Sv in winter. Moreover,it is larger in the southwest and middle section of the Kuroshio, while smaller in the northeast part. This phenomenon indicates that the position of water exchange area between the Kuroshio and the East China Sea is farther away from the axis of the Kuroshio in the on-shore direction in winter than that in summer. By analyzing the time series of the model results, the paper also reveals that the seasonal variation of the Kuroshio volume flux in the east of Taiwan presents a weakening trend after 2000 in relation to that before 2000.