Aeration of upper ocean by breaking waves
Lead Research Organisation:
University College London
Department Name: Civil Environmental and Geomatic Eng
Abstract
Advanced experimental techniques will be used to generate breaking waves in the lab, and to study the concentration and size of air bubbles produced by a single breaking event. The project aims to establish relationship between global parameters of a breaking wave-- such as spectrum and global steepness-- with local parameters of a spilling breaker and of a resulting bubble plume. Analysis of detailed ocean wave data from recent cruises will be used to assess which wave spectra are most appropriate for real conditions, and to consider the difference that this would make to the bubbles entrained by spilling breakers. Preliminary studies conducted at UCL show that the wave spectra affects bubble plume size distribution, especially in salt water. At present, the way of parametrising bubble generation by breakers assumes that one spilling breaker is the same as any other, and the preliminary work shows that this assumption is flawed. Since
these bubbles are precisely the ones that are most important for carbon dioxide transfer, this could have a major effect on accuracy of prediction of upper ocean interaction with the atmosphere.
these bubbles are precisely the ones that are most important for carbon dioxide transfer, this could have a major effect on accuracy of prediction of upper ocean interaction with the atmosphere.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509577/1 | 01/10/2016 | 24/03/2022 | |||
| 1982264 | Studentship | EP/N509577/1 | 11/12/2017 | 10/03/2022 | Konstantinos Chasapis |
| Description | Bubble clouds in the upper few meters of the ocean differ in radii sizes and residense time for different types of breaking waves. The different types of breaking waves are connected via their local characteristics (such as velocity) with the corresponding bubble populations. Achieving such a connection has implications in estimating the CO2 fluxes in the upper few meters of the ocean, because the large bubbles are carrier of such gases. |
| Exploitation Route | Bubble distributions should be used to develop better formulated bubble generation models. Bubble generation models are further used to estimate aeration during a storm in the open ocean. The upscaling from a single breaking wave case bubble statistics to the bubbles that are generated in an entire storm is the next natural step of my research. |
| Sectors | Energy,Environment |
| Description | Bubble generation models are being used for modeling of air-sea interactions in climate models which have an important role of designing the future of susstainable societes. |
| First Year Of Impact | 2020 |
| Sector | Environment |
| Impact Types | Policy & public services |
| Title | Image processing and shape detection |
| Description | Development of two image processing algorithms that identify evolving objects in high speed images. The objects are either circular/eliptical or spline alike. The method of identifying the objects if by a modified Hough transform for the circles and by using Hermite cubic splines for the curves. The two methods provide resolve bubble and wave behavour in detail. Bubbles are being identified and followed under a wave that breaks and waves shapes are extracted as they break. The former are used to develop bubble statistics. The latter are used to identify the local and global properties of a complicated breaking wave structure. The outcomes of the two methods are combined in an analysis that related bubble clouds to the kinematic and geometric properties of the breaking waves in the ocean. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2019 |
| Provided To Others? | No |
| Impact | Resolving bubble clouds in experimental conditions is both useful for both experiments but also to improve field measurements in the ocean. Such measuremtns are hard to make and by improving the methods in controlled conditions is a first step in order to compare laboratory results with real ocean readings. The fine analysis of wave crests that are generated with a unique method that matches certain cases of real ocean waves is useful in order to possibly upscale the laboratory outcomes to other facilities or even compare with ocean measurements in some cases. |