A New Method for the Estimation of Profiles of Diffusivity in the Stratified Marine Environment

Lead Research Organisation: Bangor University
Department Name: Sch of Ocean Sciences


Much of the ocean is stably stratified with lighter water overlying heavier water, with the vertical movement of nutrients, salt, heat, and pollutants across stratification driven by turbulent mixing. The nature and strength of the processes which are responsible for these vertical fluxes therefore play a major role in shaping the marine system. For example, vertical fluxes of nutrients link the dark, nutrient-rich, deep waters with the upper, sunlit, part of the water column promoting the primary productivity which supports the marine ecosystem. Vertical mixing is also one of the main mechanisms behind the large scale ocean circulation, and therefore of immense importance for the climate of our planet. A number of techniques have been developed for the estimation of vertical mixing rates in the marine environment. These include direct measurements of the turbulence using a freefalling profiler, which is a very time consuming and labour intensive technique requiring teams of specialist scientists. Other methods use acoustic current meters, which can be deployed in the marine environment and then left for a period of time. However, this method has a limited vertical range, and up until now has not worked well in environments with vertical stratification or when deployed from moving platforms. Our proposal here is to extend an acoustic technique, which we have developed, for measuring marine turbulence, using relatively cheap, off-the-shelf instruments, to the stratified marine environment. Our aim is to develop a simple to operate and effective add-on system that can be used on conventional profiling platforms (i.e. CTDs), for the measurement of profiles turbulence in a stratified marine environment. Such a system would significantly simplify measuring oceanic turbulence, facilitating more turbulence measurements and enabling an improved understanding of this important process.


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Description A new method for measuring turbulence has been developed which can be applied in low energy environments using relatively inexpensive off-the-shelf acoustic Doppler current profilers.
Exploitation Route Other can easily apply the method based on our published literature.
Sectors Aerospace, Defence and Marine,Energy,Environment

Description New method for estimating turbulence in the marine environment which is now widely used in the marine renewable energy sector in site surveys. Impact recognised as world leading in the 2014 REF (through an Impact Case Study
First Year Of Impact 2014
Sector Aerospace, Defence and Marine,Energy,Environment
Impact Types Economic

Title Estimates of the rate of dissipation of turbulent kinetic using the ADCP structure function technique from an instrument suspended from a mooring 
Description A technique orginally developed in Bangor for measuring turbulence timeseries using (relatively inexpensive) off-the-shelf instrumentation fixed on the sea bed has now been successfully extended to (i) low energy environments (from a buoy suspended on a mooring line. 
Type Of Material Improvements to research infrastructure 
Year Produced 2007 
Provided To Others? Yes  
Impact Now widely used by the marine renewables industry in site investigation and appraisal.