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Ocean currents to tell us more about our climate

October 9th, 2013 - Marine scientists in Scotland are part of an international team working on a newly funded multi-million pound project to monitor crucial ocean currents that shape Britain’s climate.

The £20 million project will focus on the North Atlantic, in particular the North Atlantic Subpolar Gyre—a system of ocean currents in the high latitude, deep-water basins of the North Atlantic Ocean. It will generate new knowledge and understanding of the gyre’s wider impacts on climate and will help improve long term climate predictions and weather forecasting.

The project, the Overturning in the Subpolar North Atlantic Program (OSNAP), will run for five years, and will involve scientists from seven countries, including a team at the Scottish Association for Marine Science (SAMS). The researchers will set up an array of moored instruments and use autonomous underwater gliders to patrol the North Atlantic, along a line from Scotland to Canada via Greenland. These will record ocean temperatures, salinity and the strength of currents continuously for four years starting next summer.

Scotland’s Education Secretary Michael Russell said: “This is an excellent example of the important research that Scottish academics and universities are involved in and the contribution we make to international scientific progress.

“The Scottish Association for Marine Science has a long involvement in the study of currents and their effect on the climate and I wish Dr Cunningham, Professor Inall and their team the best with their work over the next five years.”

The team is concentrating on the Atlantic because energy is transported around it more effectively than in the Pacific and Indian Oceans, giving the Atlantic a special role in Earth’s climate. This is due to the extensive, deep-water basins of the Labrador and Nordic Seas—high latitude seas—which draw warmer surface waters northwards all the way from the South Atlantic to the subpolar region, where that heat is transferred from the ocean to the atmosphere. This gives the UK and western Europe a much milder climate than other places at similar latitudes. Having lost its warmth to the atmosphere the cooled water sinks to great depths and flows south. Together the warm waters flowing north and the deep cold waters flowing south are called the Atlantic meridional overturning circulation, and form part of the global ocean heat conveyor.

This conveyor belt of global ocean currents is neither smooth nor continuous and the strength of currents can vary significantly. As they are strongly linked to our climate, the aim of the OSNAP monitoring array is to understand the connection between these variations and Britain’s weather.

At SAMS Dr Stuart Cunningham and Professor Mark Inall are leading the programme of purposefully designed observations of warm water flowing north past Scotland between the Iceland Basin and the Scottish continental shelf.

"This warm water path from the subtropics to the Nordic Seas has been called a “fan-assisted storage heater” because of its role in maintaining the mild UK and Western European climate some 5-10°C warmer than other regions at similar latitudes such as Siberia. However, the strength of this circulation is forecast to slow – perhaps by 25-50% - over the coming century as Earth's climate warms. To know if such a slowing is taking place we need the baseline measurements against which to assess future change, and to help interpret forecasts of climate change," explained Dr Cunningham.

SAMS is at the forefront of Atlantic overturning research. Over the past decades, SAMS scientists have developed a deep appreciation of the role of overturning circulation in climate and there’s a growing apprehension of how it will change when forced by global warming.

Professor Inall said: “In the 1970s, long before public awareness of climate change, the visionary actions of SAMS scientist David Ellett lead to the establishment of a regular measurement programme across North Atlantic Ocean. Dr Cunningham’s team at SAMS will refocus our attention on the role of the north Atlantic in UK climate at a time when climate change is high in the public consciousness. The new programme will blend traditional methods with leading edge marine robotic technologies, launched from the Scottish coast, to shed light on this question of the oceans role in UK climate.”

Funded jointly by the UK’s Natural Environment Research Council (NERC), the US’s National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA), the OSNAP project is one of two projects with a total value of £44 million. The other project, RAPID, is a collection of moored instruments that has continuously monitored the conveyor belt between the Canary Islands and Florida since 2004. RAPID is scheduled to run for an additional six years.

Science Minister David Willetts will announce the projects during his Mountbatten Memorial Lecture at the Royal Institution on Wednesday 9th October 2013.


Further information on this research project, please contact:

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