2007 年长江口邻近海域夏季上升流演变机制研究

研究长江口邻近海域夏季上升流强度和空间分布的变化,对渔业生产和赤潮的防治具有重要的指导意义.采用2007年6~10月高分辨率卫星遥感资料 NGSST 海表温度和 CCMP 风场,通过经验正交函数(EOF)分解和区域海洋数值模式(ROMS)研究了该海域夏季上升流的短期演变机制及其与 SST 异常的关系.结果表明,夏季上升流强度和范围存在明显变化,是引起该海域 SST 异常的重要原因;风场对上升流短期演变起着关键作用,风应力旋度对局地上升流变化的影响与沿岸风应力同等重要;地形变化影响着上升流中心的分布,陡而窄的海底凸起容易在顺流侧形成较强的上升流中心,并在逆流侧诱发下降流.

Mechanism of upwelling evolvement in the Yangtze River Estuary adjacent waters in summer, 2007

We utilized the high resolution satellite product, NGSST sea surface temperature (SST) and cross calibrated multi-platform (CCMP) wind data, the empirical orthogonal function (EOF) method and numerical ocean model (ROMS) to investigate the evolution of upwelling and its influence on SST anomaly in this specific region. The result indicated that the intensity and spatial distribution of upwelling in summer exhibited an evident variation, which was the key factor for the SST anomaly. The effect of the wind field was local and primarily influences its short term evolution, while the contribution of wind stress curl was on a par with the component of wind stress along the coast. The topographic variation determined the center of the upwelling, which could be induced at the strong inflow flank above the steep and narrow heave, and a corresponding downflow occurs behind the heave.