Nav: Home

Flying lab to investigate Southern Ocean's appetite for carbon

January 05, 2016

BOULDER -- A team of scientists is launching a series of research flights this month over the remote Southern Ocean in an effort to better understand just how much carbon dioxide the icy waters are able to lock away.

The ORCAS field campaign--led by the National Center for Atmospheric Research (NCAR)--will give scientists a rare look at how oxygen and carbon dioxide are exchanged between the air and the seas surrounding Antarctica. The data they collect will help illuminate the role the Southern Ocean plays in soaking up excess carbon dioxide emitted into the atmosphere by humans.

"If we want to better predict the temperature in 50 years, we have to know how much carbon dioxide the oceans and terrestrial ecosystems are going to take up," said NCAR scientist Britton Stephens, co-lead principal investigator for ORCAS. "Understanding the Southern Ocean's role is important because ocean circulation there provides a major opportunity for the exchange of carbon between the atmosphere and the vast reservoir of the deep ocean."

ORCAS is funded by the National Science Foundation's Division of Polar Programs.

"Building on decades of U.S. Antarctic Program research, new questions of global significance continue to emerge," said Peter Milne, program director of Ocean and Atmospheric Sciences in the Division of Polar Programs. "ORCAS addresses one of those questions: how the Southern Ocean affects global climate by storing, or releasing, carbon dioxide, water vapor, and heat."

Carbon dioxide, the main greenhouse gas contributing to human-caused climate change, is continually transferred back and forth between the atmosphere, plants on land, and the oceans. As more carbon dioxide has been released into the atmosphere by the burning of fossil fuels, oceans have stepped up the amount they absorb. But it's unclear whether oceans have the ability to keep pace with continued emissions.

In the Southern Ocean, studies have disagreed about whether the ocean's ability to act as a carbon sink by taking up carbon dioxide is speeding up or slowing down. Measurements and air samples collected by ORCAS--which stands for the O2/N2 Ratio and CO2 Airborne Southern Ocean Study--will give scientists critical data to help clarify what's actually happening in the remote and difficult-to-study region.

Tracking carbon by air

The ORCAS field campaign will operate out of Punta Arenas, near the southern tip of Chile. The researchers plan to use the NSF/NCAR HIAPER research aircraft to make 14 flights across parts of the Southern Ocean between Jan. 15 and Feb. 28. A suite of instruments on the modified Gulfstream V jet will measure the distribution of oxygen and carbon dioxide, as well as other gases produced by marine microorganisms, aerosols, and cloud characteristics in the atmosphere.

The flights also will observe the ocean color--which can indicate how much and what type of phytoplankton is growing in the water--using NASA's Portable Remote Imaging Spectrometer (PRISM). The addition of the PRISM instrument to the ORCAS campaign was funded by NASA.

The science campaign is being led by Stephens and NCAR scientist Matthew Long. Other principal investigators include Elliot Atlas (University of Miami), Michelle Gierach (NASA's Jet Propulsion Laboratory), Ralph Keeling (Scripps Institution of Oceanography), Eric Kort (University of Michigan), and Colm Sweeney (Cooperative Institute for Research in Environmental Sciences). CIRES is a partnership of the National Oceanic and Atmospheric Administration and the University of Colorado Boulder.

The management of the field campaign is being handled by NCAR. Logistics include everything from obtaining diplomatic clearances from multiple countries to fly through their airspaces to providing housing and workspace for project scientists in South America.

Carbon, oxygen, and phytoplankton

Measuring oxygen alongside carbon dioxide can give scientists a clearer picture of the ocean processes affecting carbon dioxide than they would get from measuring carbon dioxide alone.

"The air-sea exchange of carbon dioxide is controlled not just by physics but also by biology," Long said. "There's a nice relationship between the fluxes of oxygen and the fluxes of carbon dioxide that can be exploited to gain insight into these processes."

Carbon dioxide in the ocean is drawn into a chain of chemical reactions that buffer the impact of biological and physical ocean processes on carbon dioxide in the overlying atmosphere. Oxygen air-sea fluxes, however, are more directly tied to these same biological and physical factors. So if scientists know what's going on with oxygen, they can better understand the processes affecting carbon dioxide as well.

Additionally, if scientists know how the concentrations of the two gases change relative to one another with location and time, they can disentangle how biology and physics separately affect the ocean's ability to absorb carbon dioxide.

Physics and biology affect the ratio of carbon dioxide to oxygen in the air in different ways. In the austral spring the warmth of the returning Sun drives both carbon dioxide and oxygen out of the Southern Ocean surface and into the atmosphere. But the sunlight also triggers the growth of phytoplankton in the water. As the organisms begin to flourish, they take in carbon dioxide and release oxygen, causing the relative amounts of those two gases in the atmosphere to shift in opposite directions. Observations of these shifts can ultimately tell scientists how much carbon is going where and, more importantly, why.

A window into the deep ocean

The Southern Ocean is unique among Earth's oceans. Unimpeded by continental landmasses, and driven by a westerly wind, the Southern Ocean is able to form a circular current around Antarctica. This huge flow, the largest current on the planet, connects the adjacent Atlantic, Pacific, and Indian oceans. The complex interactions between this Antarctic Circumpolar Current and currents flowing in from other ocean basins creates an overturning circulation that brings deep water to the surface where it can exchange gases with the atmosphere before it is returned to depth.

Once it dives toward the ocean floor, that surface water--and any carbon dioxide it takes with it--can stay sequestered in the deep ocean for hundreds or even thousands of years. Data collected by the ORCAS flights will help determine how much carbon dioxide goes along for the ride.

"The Southern Ocean provides a window into the deep ocean, but it's a difficult system to simulate in our Earth system models," Long said. "It's remote, and so there has been a paucity of observations that can be used to improve the models we have."

The data generated during the field campaign will be used by the ORCAS team to improve these global computer models so they do a better job representing the complexities of the Southern Ocean. The data set, which will be managed by NCAR, will be publicly available.

While the measurements made during the ORCAS campaign will help scientists fine-tune what they know so far about the Southern Ocean, it's possible the project will also bring to light entirely new aspects of how the ocean works.

"The Southern Ocean is very inaccessible, and existing measurements are from ships or surface stations that represent only a few tiny dots on a huge map," Stephens said. "The airborne measurements we take will be helpful in terms of understanding the system better. And because we're doing something that no one's ever done before, we're likely to find things that we aren't expecting."

The NSF's Division of Polar Programs manages the U.S. Antarctic Program, through which it funds researchers, coordinates all U.S. government research on the southernmost continent, and provides logistical support needed to make the science possible.

The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under sponsorship by the National Science Foundation. Any opinions, findings and conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
-end-
On the web

#ORCAS16 Field Project http://www.eol.ucar.edu/field_projects/orcas

For news release, images, and more http://www.ucar.edu/atmosnews

National Center for Atmospheric Research/University Corporation for Atmospheric Research

Related Atmosphere Articles:

Physics: An ultrafast glimpse of the photochemistry of the atmosphere
Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.
Using lasers to visualize molecular mysteries in our atmosphere
Molecular interactions between gases and liquids underpin much of our lives, but difficulties in measuring gas-liquid collisions have so far prevented the fundamental exploration of these processes.
The atmosphere of a new ultra hot Jupiter is analyzed
The combination of observations made with the CARMENES spectrograph on the 3.5m telescope at Calar Alto Observatory (Almería), and the HARPS-N spectrograph on the National Galileo Telescope (TNG) at the Roque de los Muchachos Observatory (Garafía, La Palma) has enabled a team from the Instituto de Astrofísica de Canarias (IAC) and from the University of La Laguna (ULL) to reveal new details about this extrasolar planet, which has a surface temperature of around 2000 K.
An exoplanet loses its atmosphere in the form of a tail
A new study, led by scientists from the Instituto de Astrofísica de Canarias (IAC), reveals that the giant exoplanet WASP-69b carries a comet-like tail made up of helium particles escaping from its gravitational field propelled by the ultraviolet radiation of its star.
Iron and titanium in the atmosphere of an exoplanet
Exoplanets can orbit close to their host star. When the host star is much hotter than our sun, then the exoplanet becomes as hot as a star.
Astronomers find exoplanet atmosphere free of clouds
Scientists have detected an exoplanet atmosphere that is free of clouds, marking a pivotal breakthrough in the quest for greater understanding of the planets beyond our solar system.
Helium detected in exoplanet atmosphere for the first time
Astronomers have detected helium in the atmosphere of a planet that orbits a star far beyond our solar system for the very first time.
Mountain erosion may add CO2 to the atmosphere
Scientists have long known that steep mountain ranges can draw carbon dioxide (CO2) out of the atmosphere -- as erosion exposes new rock, it also starts a chemical reaction between minerals on hill slopes and CO2 in the air, 'weathering' the rock and using CO2 to produce carbonate minerals like calcite.
The changing chemistry of the Amazonian atmosphere
Researchers have been debating whether nitrogen oxides (NOx) can affect levels of OH radicals in a pristine atmosphere but quantifying that relationship has been difficult.
Hubble observes exoplanet atmosphere in more detail than ever before
An international team of scientists has used the NASA/ESA Hubble Space Telescope to study the atmosphere of the hot exoplanet WASP-39b.
More Atmosphere News and Atmosphere Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.