Multi-scale interactions between internal waves and rotationally modified vortices

内波和旋转修正涡之间的多尺度相互作用

基本信息

批准号：
EP/X028135/1
负责人：
Lois Baker
金额：
$ 47.71万
依托单位：
University of Edinburgh
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2023
资助国家：
英国
起止时间：
2023 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FX028135%2F1
关键词：
Multi scale interactions between internal

项目摘要

In rotating and density stratified fluids such as the ocean and atmosphere, dynamics can span a wide range of scales and dynamical regimes, from wave breaking on a beach, to circulation around entire ocean basins, and everything in-between. At large scales, the flow is dominated by rotational forces and the stabilising effect of density stratification, leading to slowly varying, rotationally constrained, horizontal flow - an example being atmospheric weather systems. This flow is in a state of near-balance between the Coriolis force due to the Earth's rotation and horizontal pressure gradients. However, at small scales, the effects of rotation and stratification are negligible, and the flow is characterised by 3D turbulence. In this project, I will study the interactions between two classes of fluid dynamical processes that occur at the intermediate scales between large-scale balanced motion and small-scale turbulence, and are therefore modified, but not constrained, by rotation: internal waves and rotationally modified vortices.Internal waves are ubiquitous in stratified flows, including the ocean and atmosphere. They overlap in scale with rotationally modified vortices for which both inertial forces and rotation are of comparable importance, termed 'submesoscale' in the ocean and 'mesoscale' in the atmosphere. Although internal waves and rotationally modified vortices have received considerable attention in recent years, their interactions are still not well understood. Here, I propose to study the way in which internal waves and rotationally modified vortices interact, including how energy is transferred between them, and how they might affect each other's generation, lifecycle, and eventual decay.These interactions will be investigated for three different flow scenarios using a theoretical framework and high-resolution numerical simulations. The modelling will be idealised and simplified, allowing me to isolate the key processes at play, whilst being motivated by real interactions that occur in the ocean and atmosphere. Oceanic observations will be used to verify results.This project is motivated by the growing consensus that internal waves and rotationally modified vortices couple large- and small- scale dynamics. Capturing this effect is a key challenge in developing the next generation of climate models, since small scales provide an essential sink of energy from the large scale flow. Whilst larger scale, balanced, flows will soon be fully resolved in climate models, rotationally modified vortices and internal waves are at the frontier of climate parameterisations, and will continue to be relevant to the UK's capability in the prediction of climate for decades to come.

在海洋和大气等旋转和密度分层流体中，动力学可以跨越广泛的尺度和动力学状态，从海滩上的波浪破碎到整个海洋盆地的环流以及其间的一切。在大尺度上，流动由旋转力和密度分层的稳定效应主导，导致缓慢变化、旋转受限的水平流动——大气天气系统就是一个例子。这种流动处于地球自转引起的科里奥利力和水平压力梯度之间接近平衡的状态。然而，在小尺度下，旋转和分层的影响可以忽略不计，并且流动以 3D 湍流为特征。在这个项目中，我将研究两类流体动力学过程之间的相互作用，这些过程发生在大规模平衡运动和小尺度湍流之间的中间尺度，因此通过旋转进行修改，但不受旋转限制：内波和旋转改进的涡流。内波在层流中普遍存在，包括海洋和大气。它们在尺度上与旋转修改的涡旋重叠，对于旋转修改的涡旋，惯性力和旋转都具有相当的重要性，在海洋中称为“亚中尺度”，在大气中称为“中尺度”。尽管近年来内波和旋转修正涡旋受到了相当大的关注，但它们的相互作用仍然没有得到很好的理解。在这里，我建议研究内波和旋转修正涡流相互作用的方式，包括它们之间的能量如何传递，以及它们如何影响彼此的产生、生命周期和最终衰变。将针对三种不同的流研究这些相互作用使用理论框架和高分辨率数值模拟的场景。建模将被理想化和简化，使我能够隔离起作用的关键过程，同时受到海洋和大气中发生的真实相互作用的激励。海洋观测将用于验证结果。该项目的动机是越来越多的共识，即内波和旋转修改的涡流耦合了大尺度和小尺度的动力学。捕捉这种效应是开发下一代气候模型的一个关键挑战，因为小尺度为大规模流动提供了重要的能量汇。虽然更大规模、平衡的流动很快将在气候模型中得到完全解决，但旋转修正涡流和内波处于气候参数化的前沿，并将继续与英国未来几十年的气候预测能力相关。