流核位置和流量变化对东海黑潮锋面弯曲影响的研究-海洋预报

流核位置和流量变化对东海黑潮锋面弯曲影响的研究

单位：1. 海军海洋水文气象中心北京 100073;
2. 青岛海洋大学物理海洋研究所山东青岛 266003

分类号：P731

出版年·卷·期（页码）：2004·2004·第一期（9-19）

摘要：

本文运用简化的坐标POM模式研究了东海黑潮锋面弯曲的产生与成长机制。主要考察了在给定的地形下,流核位置和流量变化对锋面演变的影响。当黑潮流核远离陆架时,因其锋区正好在陡的陆坡之上,斜压不稳定贡献减小,此时不论黑潮的流量强弱,其锋面都不会出现如观测所示的弯曲;当黑潮流核接近陆架时,因其锋区爬上陆架,斜压不稳定加强,小扰动能够充分发展并导致锋面弯曲,它的三维结构和观测的结果基本一致。平均波长约为250km,位相速度约为17km/d。扰动成长的主要机制是斜压不稳定,锋面弯曲的主要能源是平均有效位能。

Using the η-coordinate POM model, the effects of variation for flow core position and flux on Kuroshio frontal meander are studied. When the flow core locates away from the continental shelf, in a range of flux variation of 20Sv or 30.5Sv all perturbations move out of the domain before developing into finite amplitude meander. When the flow core location closes to the continental shelf, the continental shelf acts as a instabilizing factor, in this case the perturbations grow in amplitude and the resultant frontal meanders close to those observed. The averaged wavelength of the meander is about 250 km, and the phase speed is about 17km/day. The baroclinic instability is the predominant mechanism for the growth of disturbances, and the mean available potential energy is the main energy source for the frontal meanders.

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