March 18, 2020
The National Science Foundation (NSF) recently awarded $8.3 million to the Woods Hole Oceanographic Institution (WHOI) to extend the life of the Overturning in the Sub-polar North Atlantic Program (OSNAP) in a key part of Earth’s ocean-climate system. The award is part of a $15.5 million grant to four U.S. institutions that will help add four years to the record being assembled by the observatory.
OSNAP is maintained by researchers at WHOI, Georgia Institute of Technology, Scripps Institution of Oceanography, and the University of Miami, as well as institutions in the U.K., Canada, France, Germany, and the Netherlands. It is designed to give ocean and climate scientists an unprecedented decade-long view of the physical processes occurring across the North Atlantic that help regulate Earth’s climate and influence weather in the region.
“Observatories like OSNAP make it possible for us to see the big picture of how the ocean shapes our planet,” says WHOI President and Director Mark Abbott. “Without observing systems like these, we are blind to the changes taking place around us.”
“OSNAP epitomizes how the U.S. can help advance knowledge of our planet in ways that will enable us to make better, more informed decisions in the face of a changing climate,” says Rep. William Keating (D, Mass.). “This information will be critical as we make major financial investments in public and private coastal infrastructure on the Cape, in Massachusetts, and around the nation.”
The remote and notoriously stormy region where OSNAP is located is difficult to reach by research ship, and almost impossible in winter. It is where water flowing north from the tropics releases heat to the atmosphere as part of what’s known as the Atlantic Meridional Overturning Circulation, which helps moderate Europe’s climate and drives the global “ocean conveyor” system of currents. These currents are responsible for long-term climate variations, as well as regional weather patterns.
“We know there are important changes happening in the ocean on many timescales, from minutes to decades,” says Amy Bower, chair of the Physical Oceanography Department at WHOI and a co-principal investigator on the grant. “But unless we can keep instruments in place to sample and observe on these long timescales, we can’t see them happen.”
OSNAP consists of deep-sea moorings—some almost two miles in length—arranged in two segments across the North Atlantic: from Labrador to the southern tip of Greenland, and between Greenland and Scotland. Moorings on both segments hold a variety of instruments that gather a continuous flow of data about the ocean, including salinity, and temperature, as well as free-floating instruments released periodically by research expeditions in the region that help scientists track the pathways and strength of currents below the surface. The position of the mooring arrays and the data they collect allow scientists to observe changes over season-to-season and year-to-year timeframes in such phenomena as the flow of freshwater into the Atlantic from melting ice in Greenland and the Arctic Ocean and the transport of water from the surface to deeper depths as part of the meridional overturning circulation.
“The North Atlantic is key to our understanding of Earth’s climate and the ways our climate is changing,” says Robert Pickart, a senior scientist and physical oceanographer at WHOI who is also a co-PI on the OSNAP grant.
Data from OSNAP is already challenging researchers to fine-tune their understanding of the role the region plays in global climate and of the many processes that might affect the planet. Early results have shown, for example, that the eastern part of the basin plays a more dominant role in heat transport into the northern North Atlantic, while freshwater flows south into the North Atlantic primarily in the west via the Labrador Sea.
Extending the observational record to a full decade will help scientists better understand the seasonal to annual variations exhibited by currents in the North Atlantic, as well as the sources and impacts of freshwater flowing from the fast-warming polar region. Only with this kind of information in hand can scientists determine how the ocean is responding to, and influencing, long-term climate change. It will also help them identify the best places to monitor long-term as the climate continues to warm in decades to come.
The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment. For more information, please visit www.whoi.edu.
- $8.3 million to WHOI is part of a $15.5 million multi-institution award that will help extend the observational record of the Overturning in the Sub-polar North Atlantic Program mooring array by four years to a full decade.
- The mooring arrays and autonomous floats provide a high-resolution, broad-scale view of processes in a key part of Earth’s ocean-climate system.
- The international collaboration that began in 2014 has already yielded important results, including a more nuanced understanding of the “great ocean conveyor” system of currents that regulates global climate and influences weather in Europe.