U.S. GLOBEC: GEORGES BANK PHASE III Cross-Frontal Exchange Studies at the Base of the Tidally Mixed Front using an Injected Dye Tracer

美国GLOBEC：乔治斯银行第三阶段使用注入的染料示踪剂在潮汐混合锋面底部进行的跨锋面交换研究罗伯特·W·霍顿乔治斯银行被潮汐混合锋面包围。这条战线在维持世行高生物生产力方面的作用(它是屏障还是管道？)还没有完全被理解。有证据表明，跨锋环流可能对调节营养物质的通量和颗粒在岸上的滞留至关重要，如浮游动物和鱼苗，这两者都有助于生态系统的高生产力。我们建议使用一种特意注入的染料来直接测量潮锋脚下的混合和跨岸环流，那里的岸上通量预计最大。荧光染料示踪剂在这类研究中的效用最近在新英格兰大陆架的搁置前线得到了证明。染料沿着不断移动的锋面边界的能力使其成为研究乔治斯滩的一种特别强大的技术。由于染料斑块的扩散参考了定义锋面的温度场，因此避免了锋面位移、不规则的底部地形和波动的、强烈的沿岸流动带来的复杂性，并明确定义了跨锋面的循环和混合。染料示踪剂的测量将直接有助于我们了解使乔治斯滩成为如此高效的海洋生态系统的过程。为了管理这一资源，以保持和利用其对国家经济的最佳贡献，这种理解是必要的。这种理解也是必要的，以预测潜在气候变化对这一生态系统的强迫变化将如何影响这一宝贵的海洋资源和其他宝贵的海洋资源。该项目通过展示染料示踪剂的独特用途，将推动这项技术在未来海洋研究中的应用。

U.S. GLOBEC: GEORGES BANK PHASE III Cross-frontal exchange studies at the base of the tidally mixed front using an injected dye tracerRobert W. Houghton Georges Bank is surrounded by a tidally mixed front. The role of this front in maintaining the high biological productivity on the Bank (Is it a barrier or conduit?) is not fully understood. There is evidence that cross-frontal circulation may be critical for modulating the flux of nutrients and the retention of particles, such as zooplankton and fish larvae, on the Bank both of which contributes to the high productivity of this ecosystem. We propose to use a purposefully injected dye to directly measure the mixing and cross-bank circulation at the foot of the tidal front where on-bank flux is expected to be greatest. The utility of a fluorescent dye tracer for such studies has recently been demonstrated at the shelfbreak front on the New England Shelf. The ability of the dye to follow a constantly moving frontal boundary makes it a particularly powerful technique for studies on Georges Bank. Since the spreading of the dye patch is referenced to the temperature field that defines the front, the complexity introduced by frontal displacements, irregular bottom topography, and a fluctuating, strong along-bank flow is avoided and the cross-frontal circulation and mixing is unambiguously defined. The dye tracer measurements will contribute directly to our understanding of the processes that make Georges Bank such a highly productive marine ecosystem. This understanding is necessary in order to manage this resource to maintain and exploit its optimum contribution to the nation's economy. The understanding is also necessary to anticipate how changes in the forcing of this ecosystem by potential climate changes will affect this, and other, valuable marine resources. This project by demonstrating the unique utility of the dye tracer will advance the development of this technology for future applications in marine research.