Scottish Association for Marine Science
Subpolar North Atlantic
GBGRK - ISREY
The UK Overturning in the Subpolar North Atlantic Program (UK-OSNAP)
UK-OSNAP is a large project which aims to generate new knowledge and understanding of the North Atlantic Subpolar Gyre and its wider impacts on climate. The project duration is five years and it began on 1st September 2013. It entails activities in ocean measurement, modeling of the ocean and climate, and the analysis of results, requiring significant skills in those fields. Accordingly we assembled a team of experts from around the UK: from the National Oceanography Centre's two sites in Southampton and Liverpool, from the Scottish Association for Marine Science in Oban, from the Physics and Earth Sciences Departments of the University of Oxford, and from the Department of Earth, Ocean and Ecological Sciences of the University of Liverpool.
There is mounting evidence from measurements and models of the importance of the transports of heat and freshwater by the North Atlantic Subpolar Gyre (SPG) for impacts on North Atlantic, European and global climate via temperature, precipitation and wind strength, and also on marine ecosystems, hurricanes, even rainfall in the Sahel, the Amazon and parts of the US. The SPG behaves substantially differently from the Subtropical Gyre, and their mechanisms and timescales for transport and storage of heat and freshwater are very different. The SPG is inadequately measured, and no ocean general circulation or climate model represents it accurately. UK-OSNAP aims to generate new knowledge and understanding of the SPG, to improve predictions of the contribution of the SPG to climate. We are conducting a programme of sustained observation of SPG circulation and fluxes, coupled with the modelling and analysis required to deliver enhanced understanding of processes critical to the improvement of model physics and (ultimately) to the improvement of climate models. UK-OSNAP will form part of an international SPG measurement project, leveraging additional national and international investment in excess of £25M.
The outputs from UK-OSNAP are designed to benefit decadal and seasonal forecasters – particularly at the UK Met. Office and UK, European and international climate modellers. We aim to inform and influence international and domestic climate policy and decision makers through the reduction of the uncertainty of seasonal, decadal and longer-term model forecasts. These ultimately contribute to increasingly reliable projections of future climate, thereby underpinning mitigation and adaptation strategies. New understanding of environmental variability is highly valuable to organisations that provide advice for maintaining healthy and productive seas. Combination of OSNAP results with data from other locations will aid detection of any large-scale change in the system that may be underway, or evolve, in the coming years, likely to influence regional climate and require modified adaptation and mitigation policies to those currently in place
This cruise is completing work for the international and UK components of OSNAP. The purpose is to recover and redeploy US moorings in the Iceland Basin (Prof. William Johns, RSMAS) and UK moorings in the Rockall Trough (Prof. Stuart Cunningham, SAMS); deploy Argo floats to sustain the distribution of North Atlantic floats (Jon Turton, UK Met. Office); deploy RAFOS floats targeted to depths of the deep overflows (Dr Amy Bower, WHOI); deploy and recover Seagliders in the Hatton-Rockall Plateau (Prof. Mark Inall, SAMS); deploy and recover Spray gliders in the Iceland Basin (Prof. Dalei Song, Ocean University China). Standard CTD-LADCP sections will be occupied and routine shipboard observations of underway meteorology, sea-surface properties and ocean currents will be monitored.
Further information about the OSNAP program can be found here and here.