From internal waves to microscale breakers: towards understanding their role in large-scale processes

湖泊、海洋和大气都是密度分层的流体。在湖泊中，分层最常见的原因是温度变化，寒冷稠密的水位于较轻、温暖的表层水之下。有时盐的存在有助于分层。在海洋中，温度和盐度的变化都很重要。分层的一个后果是内部重力波的存在，这种波在湖泊、海洋和大气内部无处不在。这些波是由作用于垂直位移流体的重力恢复力驱动的。在湖泊和海洋的表面，可以发现表面水波。这里重力恢复力和表面张力起作用。在小于几厘米的长度尺度上，表面张力显著地改变了表面波的性质。

Lakes, the oceans and the atmosphere are all density stratified fluids. In lakes the stratification is most often due to temperature variations, with cold dense water lying beneath lighter, warm surface waters. Sometimes the presence of salts can contribute to the stratification. In the ocean variations in both temperature and salinity are important. One consequence of the stratification is the presence of internal gravity waves which are ubiquitous in the interior of lakes, oceans and the atmosphere. These waves are driven by gravitational restoring forces acting on vertically displaced fluids. At the surface of lakes and oceans, surface water waves are found. Here gravitational restoring forces as well as surface tension forces come in to play. Surface tension significantly modifies the properties of surface waves at length scales less than a few centimeters.