The UK Overturning in the Subpolar North Atlantic Program (UK-OSNAP)

Lead Research Organisation: University of Liverpool
Department Name: Earth, Ocean and Ecological Sciences

Abstract

UK-OSNAP: Summary

What is climate? The sun's energy is constantly heating the Earth in equatorial regions, while in the Arctic and Antarctic the Earth is frozen and constantly losing heat. Ocean currents and atmospheric weather together move heat from the equator towards the poles to keep the Earth's regional temperatures in balance. So climate is simply the heat moved by ocean currents and by the weather. Earth's climate is warming: the average temperature of the Earth is rising at a rate of about 0.75 degrees Centigrade per hundred years, caused by carbon dioxide in the atmosphere trapping heat that is normally lost to space. Can we forecast how climate might change in the future?

There is an old adage that rings true: "Climate is what you expect; weather is what you get". Hot weather in one summer does not tell us that climate is changing because the weather is so variable day-to-day and even year-to-year. We need to average over all the weather for a long time to decide if the climate is changing. We would like to know if the climate is changing before our descendants face the consequences, and that is where our project comes in. The ultimate ambition of climate scientists is nothing less than forecasting climate up to 10 years in advance.

Is this possible? After all we know weather forecasts become somewhat unreliable after three to five days. The answer is yes because of the ocean. Slow and deep currents give the ocean a memory from years to hundreds of years, and the ocean passes this memory onto the climate. If we know the condition of the ocean now, then we have a good chance of understanding how this will affect the climate in years to come.

We have set ourselves a huge task, but will be helped by colleagues in the US, Canada, Germany, Netherlands, Faroe Islands, Iceland, Denmark and Scotland. We will continuously measure the ocean circulation from Canada to Greenland to Scotland (the subpolar North Atlantic Ocean). This has never been attempted before. We have chosen the North Atlantic because the circulation here is important for the whole of Earth's climate. This is because in the high latitudes of the North Atlantic, and the Arctic Ocean that it connects to, the ocean can efficiently imprint its memory on the atmosphere by releasing the huge amounts of heat stored in it. In the UK we are on the same latitude as Canada and Siberia, and the Shetland Islands are further north than the southern tips of Greenland and Alaska, but the Atlantic Ocean circulation keeps the UK 5-10 degrees Centigrade warmer than those other countries.

We can measure across an entire ocean by deploying reliable, self-recording instruments. We will use moorings (wires anchored to the seabed and supported in the water by air-filled glass spheres) to hold the instruments in the important locations. Every year from 2014 to 2018 we will use ships to recover the moorings and the data, then put the instruments back in the water. We will also use exciting new technology. Autonomous underwater Seagliders will fly from the surface to 1 km depth on year long-missions surveying the ocean, from Scotland to 2000 km westward into the Atlantic. The Seagliders transmit their data to our lab every day via satellite, and the pilot can fly the glider remotely. Also there is a global fleet of 3000 drifting floats to continuously measure the top 1 km of the ocean. Satellites provide important measurements of the ocean surface. With these new measurements, we will find how the heat carried by the ocean changes through the months and years of the project, and we will use complex computer models to help explain what we find.

Planned Impact

Beneficiaries and how do they benefit?

Decadal and seasonal forecasters. Knowledge of the structure, behaviour and state of the sub-polar Atlantic is crucial to the skill of forecasting systems. OSNAP will provide observations to accurately form essential starting conditions, benefitting the UK Met. Office 'DePreSys' team.

UK, European and international climate modelers. The observations will provide valuable data to enable assessment, and subsequent refinement, of coupled ocean/climate models used for prediction. Modeling groups at UK Met. Office Hadley Centre and the UK National Centre for Ocean Forecasting will benefit. We will prepare tailored progress presentations for the Hadley Centre. Maximum benefit to the international climate modeling community will be ensured through links in the international OSNAP programme (US, Germany, Netherlands, Canada, France).

International and domestic climate policy and decision makers. Refinement of seasonal, decadal and climate models will contribute to increasingly reliable projections of future climate, thereby underpinning mitigation and adaptation strategies. International benefactors include future assessments by the Intergovernmental Panel on Climate Change (IPCC), which synthesises international modeling work for the policy-making community; and also the International Council for the Exploration of the Seas (ICES) and the Northwest Atlantic Fisheries Organization (NAFO). Domestic beneficiaries include the Depts. of Energy and Climate Change (DECC) and Environment, Food and Rural Affairs (DEFRA); the Foreign and Commonwealth Office (FCO) Polar Desk; and the Scottish Government whose territorial waters extend into the region. The combination of OSNAP results with data from other locations, notably RAPID-WATCH 26N and the Nordic Seas (EU projects NACLIM and THOR), will aid detection of large-scale change in the system likely to influence regional climate and require modified adaptation/mitigation policies.

We will manage our User Community List for climate policy-making for circulating notification and summaries of relevant publications. We will engage with users (known and new) and assist with the extraction, presentation and analysis of OSNAP data; we will make extensive use of a website. We will publish an annual Project Summary Briefing for the climate policy community, outlining project progress and key findings. We will work with the UK Marine Climate Change Impacts Partnership and the UK Climate Impacts Programme to ensure that findings are included in their reports including the 'Annual Report Card' and the AMOC Stakeholder Guidance Note. We will visit key policymakers throughout the project, and invite them to our Project's final UK meeting, shaping part of this meeting towards delivery of Project results within a user context.

Outreach. Ocean science is an exciting and engaging topic for the general public, particularly children. UK-OSNAP will showcase physical science and technology and inspire children in the science and engineering elements of the curriculum. The Scottish Ocean Explorer Centre in Oban will highlight the cutting edge technology with a particular focus on gliders, utilising live feeds of the incoming data and displays showing the tracks of the gliders. The highly-regarded oceans4schools.com website (Southampton) will carry regular features for pupils and teachers. The press offices of NERC, NOC, SAMS and U. Oxford will be kept appraised of newsworthy developments. We will exploit the publicity opportunities afforded by annual NOC & University Open Days. We will maintain cruise blogs targeted at non-scientific audiences.

We will disseminate findings by publication of articles in high-impact refereed journals and presentations at key international science conferences. We will develop a project website to act as a point of access for users of our results, reports and value-added data products.
 
Description Observational analyses reported in a Science paper identifies that the Labrador Sea only generates a small proportion of the variability in the North Atlantic meridional overturning, contrary to most diagnostics of climate models. The main cause of the variability in the meridional overturning are contributions from between Greenland and Scotland.
Exploitation Route Relevant for the Hadley Centre and the UK Met Office in terms of decadal forecasts.
Sectors Education,Environment

URL http://www.ukosnap.org