Details of Award
NERC Reference : NE/Z000408/1
NSFGEO-NERC: Direct comparison of ocean temperature and velocity structure from in-situ measurements and distributed optical fiber sensing
Grant Award
- Principal Investigator:
- Dr M Belal, National Oceanography Centre, Science and Technology
- Co-Investigator:
- Professor A Naveira Garabato, University of Southampton, Sch of Ocean and Earth Science
- Grant held at:
- National Oceanography Centre, Science and Technology
- Science Area:
- Marine
- Overall Classification:
- Panel A
- ENRIs:
- Biodiversity
- Environmental Risks and Hazards
- Global Change
- Natural Resource Management
- Pollution and Waste
- Science Topics:
- Ocean Circulation
- Deep convection
- Deep ocean circulation
- Internal waves
- Marine boundary layer
- Meridional overturning circ
- Ocean modelling
- Ocean turbulence
- Oceanic eddies
- Shelf ocean dynamics
- Abstract:
- Despite the many significant leaps in understanding brought about by technological progress in ocean observations, a crucial blind spot remains in our ocean observing capabilities: currently, no established approach exists to robustly measure the ocean interior at horizontal resolutions of O(10-100 m) over any meaningful spatio-temporal scales, e.g., continuous horizontal distances of many kms over times of weeks to years. This gap has limited our understanding of a breadth of oceanic processes operating on those scales, and has prevented testing of new theoretical concepts or model-based predictions of the dynamics and large-scale impacts of such processes. Important oceanic phenomena lying within the above observational blind spot permeate almost every topical problem in physical oceanography and marine biogeochemistry. Measurement by moored or autonomous systems is either highly restricted in space (for moorings) or heavily aliased in both space and time (for autonomous systems). Unlocking progress in tackling these (and many related) problems thus requires a new way of observing the ocean - one that enables concurrent resolution of fine horizontal and vertical scales with a spatio-temporal outreach that is sufficiently extensive to sample many events of the target phenomenon. This project investigates a new, low-cost, and environmentally friendly passive approach to remote sensing of the ocean, which takes advantage of the ambient random wave motion (noise) and the ability to quantitatively characterize this motion with high spatial and temporal resolution using distributed optical fibre sensing within legacy seafloor infrastructure of power and telecommunication cables. In a wide range of frequencies spanning from below 1 mHz to hundreds of kHz and encompassing acoustic and gravity waves, ocean waves create pressure fluctuations, which can be harnessed to interrogate the ocean and measure physical parameters of the water column, ice cover, and the seabed. By cross-correlating the pressure or particle acceleration fluctuations at different locations, noise interferometry retrieves approximations to Green's functions of various waves, which then serve as the input data for passive ocean remote sensing. The proposed approach of passive noise interferometry replaces signals from a powerful, compact wave source with averaging extensive datasets comprising contributions of multiple spatially distributed random sources. Application of noise interferometry to monitoring the ocean proves to be more complex than in seismology for several reasons, the main one being the much shorter time scales of water column variability compared to solid earth, which drastically limits useful noise averaging times in retrieving cross-correlation function. Other difficulties include the need to maintain sub millisecond accuracy of the clocks on underwater moorings for months-long periods and to transfer massive amounts of data from autonomous moorings located away from shore. These problems can be resolved if, instead of using the traditional hydrophones or seismometers (which are sparsely spread point sensors), data are obtained through use of dynamics distributed optical fibre sensing within offshore legacy seafloor cable(s), without interfering with the normal operations of such cables. This project coherently combines the attributes of passive noise interferometry with dynamic distributed optical fibre sensing to characterize the physical properties of the ocean (temperature, pressure, current velocity etc.), albeit spatially resolved through the bulk of the water column by using the seafloor configuration of legacy offshore cables of telecommunication and/or energy.
- NERC Reference:
- NE/Z000408/1
- Grant Stage:
- Awaiting Event/Action
- Scheme:
- Standard Grant FEC
- Grant Status:
- Active
- Programme:
- Lead Agency Grant
This grant award has a total value of £313,596
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Investigators | DA - Estate Costs | DA - Other Directly Allocated | DI - T&S |
|---|---|---|---|---|---|
| £21,008 | £104,303 | £38,257 | £46,323 | £87,937 | £15,767 |
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