Acoustics, small-scale physics and bio-physics in the ocean

声学打开了一扇揭示水下世界的窗户。光无法到达海洋深处，所以通常“看到”远处的东西的唯一方法是通过观察反射的声波而不是光波。在将近四分之三的世纪里，海洋学家们一直使用声纳技术来了解海洋内部。然而，这个强大的工具确实有一些局限性。很难区分不同的散射源。这使得应用定量数据分析来确定鱼类或浮游生物的浓度，或者相互作用的洋流之间的混合量变得非常棘手。这些并不是纯粹的学术目标，因为声学调查被用来帮助预测鱼类和浮游动物的数量，从而影响海洋政策的决定。能够利用声学定量测量洋流的混合将大大提高我们进行这种测量的能力;混合信息的缺乏是阻碍气候和气候变化模型可靠性的主要因素之一。

Acoustics opens a window revealing an underwater world. Light cannot reach the oceans' depths, so often the only way to "see" something at a distance is through the observation of reflected sound waves rather than light waves. For nearly three quarters of a century oceanographers have used sonar technology to learn about the ocean interior. This powerful tool does, however, have some limitations. It is difficult to distinguish between different sources of scatter. This makes it tricky to apply quantitative data analysis to determine concentrations of fish or plankton, or the amount of mixing between interacting ocean currents. These are not purely academic goals, as acoustic surveys are used to help make predictions of fish and zooplankton stocks and thus impact marine policy decisions. Being able to quantitatively measure the mixing of ocean currents using acoustics will dramatically increase our ability to make this type of measurement; the dearth of mixing information is one of the major factors hampering the reliability of climate and climate change models.