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Sensors for LArge scale HydrodynaMic Imaging of ocean floor

Periodic Reporting for period 3 - LAkHsMI (Sensors for LArge scale HydrodynaMic Imaging of ocean floor)

Reporting period: 2018-04-01 to 2019-09-30

The main objective of LAkHsMI is to build macroscopic scalable sensor arrays for hydrodynamic visualization and large-scale oceanography. With LAkHsMI sensors we expect to significantly improve the quality of benthic (near bottom) marine observations and reduce uncertainty of modelling ocean physics at a tolerable cost. Currently, the bottom layers of oceans are under sampled because there is no technology for recording motion of water under the surface with a sufficient resolution and scale.
Understanding the benthic flows in oceans is important for modelling and predicting the circulation in oceans. This is turn is important for the society to understand climate change, ocean productivity, pollution, weather, etc.
The overall objectives of LAkHsMI are:
Objective 1: Design of low-cost, scalable optical sensors for hydrodynamic imaging.
Outcome of Objective 1: two types of sensor arrays have been developed - optical and electrical - for measuring flow.
Objective 2: Prototyping of sensors, imaging, and fabrication methods.
Outcome of Objective 2: fabrication methods of the sensors and methods of data acquisition and analysis are developed.
Objective 3: Testing and performance assessment of the LAkHsMI sensor arrays under laboratory and pool conditions.
Outcome of Objective 3: the sensor arrays are demonstrated to be able to recognise objects moving in the flow on a laboratory scale (<1m) and pool scale (10 m).
Objective 4: Developing methods for data acquisition, storage and on-site real-time analysis ensuring compatibility with standards of existing operational observation systems as endorsed by the European Global Ocean Observing System organization (EUROGOOS) and further developed by Copernicus/MyOcean initiatives.
Outcome of Objective 4: online data streaming compatible with Copernicus Marine services has been demonstrated for oceanographic data acquisition on field trials.
Objective 5: LAkHsMI sensor data processing and data analysis for hydrodynamic imaging, classification of hydrodynamic environments, detection and classifications of objects.
Outcome of Objective 5: data acquisition, analysis and classification algorithms have been developed for detecting moving objects in water on lab (<1m scale), pool (10 m scale) and field (> 1km scale) scale.
Objective 6: Testing and performance assessment of LAkHsMI sensors in natural conditions.
Outcome of Objective 6: LAkHsMI sensors have been field tested for investigating flow and turbulence of high-energy flows (at marine renewables testsites), for oceanographic applications (dynamics of thermocline), for detection and analysis of shipwakes, measuring flows in harbour areas.
Objective 7: Implementation of dissemination and exploitation including IPR strategy, manufacturing methods, possible business models and use-cases.
Outcome of Objective 7: two patents have been filed on LAkHsMI technology, several use-cases have been tested for applications in oceanography, aquaculture, harbour safety and environmental monitoring. First commercial pilot installation has been deployed. Exploitation plan is completed and will be used for further commercialisation of LAkHsMI technology.
LAkHsMI project has developed new technologies for measuring natural flows at high spatial and temporal resolution. It means that we can deploy an array or network of novel flow sensors that measure flow field in more than one point. It also means that we can measure flow at high frequency and therefore not just capture the average flow direction and magnitude but also its fluctuations and changes. This gives us more detailed information about natural flow fields. We have also developed algorithms for processing the sensor signals interpreting them. The sensors and algorithms have been demonstrated for several applications. We have shown that the array of flow sensors can be used to detect and classify objects moving in the water. This has been experimentally shown on a lab scale (<1m), pool scale (10m, classifying shapes of moving objects) and field scale (detecting wakes of ships). The LAkHsMI array for oceanographic applications has been demonstrated on large-scale long-term field trial (80 days, 1,1 km) for measuring and analysing the dynamics of thermocline. We have also shown that we can capture the dynamics of flow field in high-energy flows (possible deployment sites for marine renewables). Moreover we have identified new possible application areas where distributed flow sensing creates new knowledege and brings new value, such as aquaculture, harbour safety and environmental monitoring.
LAkHsMI technology permits distributed flow sensing. With current technology it is too expensive or not possible to record flow changes at high frequency and in several place to investigate how flow field changes in space and time. Current technologies (acoustic measurement technologies and propellers) measure at low frequency and deliver mean flow measurements but not their fluctuations in time. They are usually also point measurements, which means that if the flow magnitude and direction changes in space, this is not captured properly. Moreover, acoustic measurement technologies do not function near objects and surfaces (such as sea-bottom, walls, rocks or underwater vegetation). One of the main outcome of the project is measuring benthic (near bottom) currents for oceanographic applications which gives new knowledge in physical oceanography but we can also measure how flow changes around underwater structures or how vegetation changes the flow field. This makes possible to better design underwater structures (e.g. marine renewable installations) and monitor the movement of water around existing ones (harbours, fish farms, etc). It also will help to understand environmental processes, such as sediment transportation, impact of underwater vegetation etc.