FASTNEt - Fluxes Across the Sloping Topography of the North East Atlantic
Lead Research Organisation:
Bangor University
Department Name: College of Natural Sciences
Abstract
Shallow seas, the Shelf Seas, surround almost all of the Earth's land masses. On average shelf seas are hundreds of meters deep, compared to the average depth of the ocean of nearly four kilometres. Shelf Seas may be as narrow as a few kilometres, or as wide as hundreds of kilometres and together they occupy only a tenth of the watery part of the world. Yet they exert an effect on humanity far out of proportion to their mere size. Shelf Seas around the UK and western Europe are particularly wide (10s to 100s km) and shallow (around 150m); they are beset by strong tides, westerly winds, and fed by the warm waters of the NE Atlantic. From the smallest plant life, phyto-plankton, to the fish, UK Shelf Seas are highly biologically productive: nine tenths of the world's commercial fish catches come from shelf seas. This high productivity is fuelled to the greatest extent by the movement of nutrient-rich ocean waters onto the Shelf Seas. However, the step seabed slope (the Shelf Edge), which marks a narrow zone separating ocean from shelf, acts to reduce the movement of water from ocean to shelf (and visa versa); major ocean currents do not like to cross a sloping seabed. This restriction to exchange, however, breaks down when oceanic flows feel the wind or the seabed, or vary more rapidly than daily or over distances shorter that a few tens of kilometres.
The shelf edge is therefore seen as the controlling gateway to exchange between ocean and shelf, and the gatekeepers of that exchange are flows which change quickly, or lie at the very surface or at the very bottom of the sea. This makes the gatekeepers of exchange difficult to measure, and as a result we know very little about how the gatekeeper processes change from one season to another and from one year to another.
FASTNEt will bring together the strongest possible UK team of Physical Oceanographers to tackle this challenge using state-of-the art observational technologies, and a range of predictive modelling approaches.
Two research ship expeditions will study the details of the gatekeeper processes, aided by satellite tracked drifting buoy, fluorescent dyes, and unmanned mini-submarines. Instruments will be left in place over winter to record changes brought by winter storms, and a fleet of unmanned submarines will visit these instruments in conditions no ship could operate in, and is so doing fill a huge gap in our understanding.
We will take the information gathered from the submarines, drifters, satellite pictures and ships and test our understanding of the gatekeeper processes, improve models designed to simulate these processes. We will then work with the National Centre for Ocean Forecasting to help improve our ability to provide forecasts of the conditions of the seas surrounding the United Kingdom.
The shelf edge is therefore seen as the controlling gateway to exchange between ocean and shelf, and the gatekeepers of that exchange are flows which change quickly, or lie at the very surface or at the very bottom of the sea. This makes the gatekeepers of exchange difficult to measure, and as a result we know very little about how the gatekeeper processes change from one season to another and from one year to another.
FASTNEt will bring together the strongest possible UK team of Physical Oceanographers to tackle this challenge using state-of-the art observational technologies, and a range of predictive modelling approaches.
Two research ship expeditions will study the details of the gatekeeper processes, aided by satellite tracked drifting buoy, fluorescent dyes, and unmanned mini-submarines. Instruments will be left in place over winter to record changes brought by winter storms, and a fleet of unmanned submarines will visit these instruments in conditions no ship could operate in, and is so doing fill a huge gap in our understanding.
We will take the information gathered from the submarines, drifters, satellite pictures and ships and test our understanding of the gatekeeper processes, improve models designed to simulate these processes. We will then work with the National Centre for Ocean Forecasting to help improve our ability to provide forecasts of the conditions of the seas surrounding the United Kingdom.
Planned Impact
see lead proposal
Publications
Carless S
(2016)
Effects of future sea-level rise on tidal processes on the Patagonian Shelf
in Journal of Marine Systems
Green J
(2017)
Explicitly modelled deep-time tidal dissipation and its implication for Lunar history
in Earth and Planetary Science Letters
Green J
(2013)
Non-assimilated tidal modeling of the South China Sea
in Deep Sea Research Part I: Oceanographic Research Papers
Green J
(2013)
A Comparison of Tidal Conversion Parameterizations for Tidal Models
in Journal of Physical Oceanography
Green J
(2015)
Climatic Consequences of a Pine Island Glacier Collapse
in Journal of Climate
Haigh I
(2020)
The Tides They Are A-Changin': A Comprehensive Review of Past and Future Nonastronomical Changes in Tides, Their Driving Mechanisms, and Future Implications
in Reviews of Geophysics
Hopkins J
(2014)
Storms modify baroclinic energy fluxes in a seasonally stratified shelf sea: Inertial-tidal interaction
in Journal of Geophysical Research: Oceans
Inall M
(2021)
Shelf Seas Baroclinic Energy Loss: Pycnocline Mixing and Bottom Boundary Layer Dissipation
in Journal of Geophysical Research: Oceans
Palmer M
(2013)
Variable behavior in pycnocline mixing over shelf seas
in Geophysical Research Letters
Palmer M
(2015)
Turbulence and mixing by internal waves in the Celtic Sea determined from ocean glider microstructure measurements
in Journal of Marine Systems
Description | We now have a capability to accurately measure vertical mixing by using ocean gliders with specific turbulence equipment attached. Work from cruise D376 show that the Ocean Mixing Glider (OMG) produces very similar results to those obtained from conventional free falling profilers. This is significant step forward in our ability to obtain long-term observations of vertical mixing in the ocean. This new data, together with other observations, has suggested that severe wind events may have an impact on the shelf sea vertical transports long after the wind have died down. This is because the wind changes the vertical temperature structure of the ocean and this affects how wave motions within the water column can move and how energetic they are. We have also shown that there is a bias in calculations of internal tidal energy fluxes when the surface tide is too strong. This therefore applies to most observations in shelf seas. A correction is suggested. |
Exploitation Route | This new technique has lead to a capability to get continuous autonomous measurements of turbulence for several weeks, something which previously would have required a very large investment in trained staff. The new energy flux result will be of importance for a wide international community, as evidenced by the interest for the owrk at conferences. |
Sectors | Aerospace Defence and Marine Environment |
Description | Deeming Summer Bursary |
Amount | £1,500 (GBP) |
Organisation | Bangor University |
Sector | Academic/University |
Country | United Kingdom |
Start | 05/2014 |
End | 09/2014 |
Description | Were tides resonsible for the low oxygen levels during the Turonian mass extinction? |
Organisation | European Centre for Research and Teaching of Environmental Geosciences (CEREGE) |
Country | France |
Sector | Academic/University |
PI Contribution | Tidal model simulations to be used in a climate model of the Turonian (95Ma). |
Collaborator Contribution | The French team has provided bathymetry and stratification data for the Turonian, to be used in the tidal model i base my work on. |
Impact | none to date. |
Start Year | 2016 |
Description | AGU OS 2018 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | Gave three presentations at the 2018 AGU Ocean Sciences meeting, including work on deep-time tides, tides and sea-level rise, and mixing in the Arctic. |
Year(s) Of Engagement Activity | 2018 |
Description | AGU Ocean Sciences |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other academic audiences (collaborators, peers etc.) |
Results and Impact | Science conference presentations, including convening sessions collaborations spawned; exchange of information |
Year(s) Of Engagement Activity | 2010,2012,2014 |
Description | SOS Sea food festival |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | my display introduced the public to the concept of tides and how they help control climate, including discussions about the subject. None yet. |
Year(s) Of Engagement Activity | 2014 |