More than 30 scientists - including one from John C. Stennis Space Center - will embark next week on a research mission to the Southern Ocean. Researchers will battle the elements to study how gases important to climate change move between the atmosphere and the ocean under high winds and seas.
NASA, the National Oceanic and Atmospheric Administration (NOAA), and the National Science Foundation are sponsoring the Southern Ocean Gas Exchange Experiment, a six-week research expedition aboard the NOAA ship Ronald H. Brown, which departed Feb. 28 from Punta Arenas, Chile. The Ronald H. Brown is a state-of-the-art oceanographic research platform and, at 274 feet, it is the largest research vessel in the NOAA fleet.
Participating in the Southern Ocean expedition will be Dr. Richard Miller, an oceanographer in the Science & Technology Division at NASA's Stennis Space Center in Mississippi.
Miller and scientists from dozens of universities and research institutions will measure turbulence, waves, bubbles, temperature and ocean color, and investigate how these factors relate to the air-sea exchange of carbon dioxide and other climate-relevant gases. Their research will help improve the accuracy of climate models and predictions.
Miller's research will focus on measuring the distribution and changes of colored dissolved organic matter (CDOM) in the water. Because organic matter changes to carbon dioxide as it degrades, it's a critical element in NASA's understanding of the global carbon cycle. CDOM changes the color of the water by absorbing light and allows research-ers to detect these changes using NASA remote sensing technologies.
Miller will analyze his water samples using an instrument called the UltraPath, which was developed through an innovative partnership between NASA's Stennis Space Center and World Precision Instruments, a private company in Sarasota, Fla. The Ultrapath is used to determine the contribution of CDOM to the spectral absorption of light.
It is estimated that the world's oceans absorb about 2 billion metric tons of carbon from the atmosphere every year, which is about 30 percent of the total annual global emissions of carbon dioxide. Scientists know higher wind speeds promote faster exchange of gases, but there have been very few studies aimed at directly measuring these exchanges under real world conditions where other factors, such as breaking waves observed in the Southern Ocean, can influence the process. This research will help to better understand these processes because it will be conducted by an interdisciplinary team in an understudied region of the world's ocean.
"NASA's ongoing effort to understand the global carbon cycle will benefit from the data this cruise will produce about the mechanisms that govern gas transfer in this remote part of the world's ocean," said Paula Bontempi, manager of NASA's ocean biology and biogeochemistry research program at NASA Headquarters in Washington. "NASA's global satellite observations of ocean color that reveal so much about the health of our oceans also will be improved in this region as we validate what our space-based sensors see with direct measurements taken at sea."
NASA's Aqua satellite makes ocean color observations over the Southern Ocean every few days with the Moderate Resolution Imaging Spectroradiometer. The satellite, launched in 2002, uses six instruments to make global measurements of the atmosphere, land, oceans, and snow and ice cover.
The Southern Ocean covers a vast area and has some of the roughest seas found on Earth.
"It is the largest ocean region where the surface waters directly connect to the ocean interior, providing a pathway into the deep sea for carbon dioxide released from human activities," said Christopher Sabine, an oceanographer at NOAA's Pacific Marine Environmental Laboratory, Seattle, and co-chief scientist on the cruise.
"Understanding how atmospheric carbon dioxide is absorbed into these cold surface waters under high winds speeds is important for determining how the ocean uptake of carbon dioxide will respond to future climate change."
"We will be directly assessing the rate and mechanism by which the ocean is taking up carbon and releasing it," said cruise co-chief scientist David Ho of Lamont-Doherty Earth Observatory of Columbia University, Palisades, N.Y. "This is the first U.S.-led effort to use all the state-of-the-art tools that we have to quantify gas exchange in the Southern Ocean. After years of planning, it is extremely satisfying to see the experiment finally take place."
For more information on the experiment on the Web, visit: http://so-gasex.org.
For information about NASA and agency programs on the Web, visit: http://www.nasa.gov/home.
For information about Stennis Space Center, visit: http://www.nasa.gov/centers/stennis/.
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