Collaborative Research: Exploring the Role of Internal Wave Generation in Gravity Currents

由于稠密海洋重力流中的卷吸作用对海洋翻转环流具有重要意义，过去人们对其进行了深入的研究。这些研究对产生夹带的实际过程只有很少的研究，而且历史上没有将内部重力波(IGW)的产生与重力流联系起来。这与大气下坡风流的许多大气研究形成对比，在这些研究中，IGW的产生被发现是一个基本的过程，并对大量的动量转移负责。在海洋溢出中，很少有历史观测能够捕捉到探测内波产生所需的尺度。然而，根据对有限可用数据的重新分析，至少有一些溢出具有有利于IGW产生的垂直结构和时间尺度范围。我们假设IGW的产生代表着地中海外流(Med Outflow)中的动量下沉。该项目将与西班牙科学家合作，研究在地中海外流中IGW的存在、特征和动态作用。计划进行两次短期系泊和密集的船上LADCP/CTD调查，以探索IGW结构，并检查它是否可能对重力流动力学和卷吸作用重要。这项研究为启动国际、欧美合作提供了一个战略机遇。

Entrainment in dense oceanic gravity currents has been studied intensively in the past owing to its importance for the oceanic overturning circulation. These studies contain only little examination of the actual processes that produce the entrainment, and have historically not been linked the generation of internal gravity waves (IGWs) with gravity current flows. This contrasts many atmospheric studies of atmospheric down slope wind flows in which IGW generation has been found to be an essential process and responsible for a significant amount of momentum transfer. In oceanic overflows, few historical observations capture the scales necessary to detect internal wave generation. However, based on a reanalysis of the limited available data, at least some overflows have a vertical structure and range of temporal scales conducive to IGW generation. We hypothesize that IGW generation represents a momentum sink in the Mediterranean Outflow (Med Outflow). The project will examine the presence, characteristics, and dynamic role of IGWs in the Med Outflow in collaboration with Spanish scientists. Two short-term moorings and intensive shipboard LADCP/CTD surveys are planed to explore the IGW structure and to examine if it is likely to be important for gravity current dynamics and entrainment. This study offers a strategic opportunity to initiate an international, European-American collaboration.