NASA Mission Will Observe Earth's Salty Seas

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
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http://www.jpl.nasa.gov

News Release: 2011-146 May 17, 2011

NASA Mission Will Observe Earth's Salty Seas

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-146&cid=release_2011-146

PASADENA, Calif. – Final preparations are under way for the June 9 launch of the international
Aquarius/SAC-D observatory. The mission's primary instrument, Aquarius, will study interactions
between ocean circulation, the water cycle and climate by measuring ocean surface salinity.

Engineers at Vandenberg Air Force Base in California are performing final tests before mating
Aquarius/SAC-D to its Delta II rocket. The mission is a collaboration between NASA and
Argentina's space agency, Comision Nacional de Actividades Espaciales (CONAE), with
participation from Brazil, Canada, France and Italy. SAC stands for Satelite de Applicaciones
Cientificas. Aquarius was built by NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the
agency's Goddard Space Flight Center in Greenbelt, Md.

In addition to Aquarius, the observatory carries seven other instruments that will collect
environmental data for a wide range of applications, including studies of natural hazards, air quality,
land processes and epidemiology.

The mission will make NASA's first space observations of the concentration of dissolved salt at the
ocean surface. Aquarius' observations will reveal how salinity variations influence ocean circulation,
trace the path of freshwater around our planet, and help drive Earth's climate. The ocean surface
constantly exchanges water and heat with Earth's atmosphere. Approximately 80 percent of the global
water cycle that moves freshwater from the ocean to the atmosphere to the land and back to the
ocean happens over the ocean.

Salinity plays a key role in these exchanges. By tracking changes in ocean surface salinity, Aquarius
will monitor variations in the water cycle caused by evaporation and precipitation over the ocean,
river runoff, and the freezing and melting of sea ice.

Salinity also makes seawater denser, causing it to sink, where it becomes part of deep, interconnected
ocean currents. This deep ocean "conveyor belt" moves water masses and heat from the tropics to the
polar regions, helping to regulate Earth's climate.

"Salinity is the glue that bonds two major components of Earth's complex climate system: ocean
circulation and the global water cycle," said Aquarius Principal Investigator Gary Lagerloef of Earth
& Space Research in Seattle. "Aquarius will map global variations in salinity in unprecedented detail,
leading to new discoveries that will improve our ability to predict future climate."

Aquarius will measure salinity by sensing microwave emissions from the water's surface with a radiometer instrument. These emissions can be used to indicate the saltiness of the surface water, after accounting for other environmental factors. Salinity levels in the open ocean vary by only about five parts per thousand, and small changes are important. Aquarius uses advanced technologies to detect changes in salinity as small as about two parts per 10,000, equivalent to a pinch (about one-eighth of a teaspoon) of salt in a gallon of water.

Aquarius will map the entire open ocean every seven days for at least three years from 408 miles (657 kilometers) above Earth. Its measurements will produce monthly estimates of ocean surface salinity with a spatial resolution of 93 miles (150 kilometers). The data will reveal how salinity changes over time and from one part of the ocean to another.

The Aquarius/SAC-D mission continues NASA and CONAE's 17-year partnership. NASA provided
launch vehicles and operations for three SAC satellite missions and science instruments for two.

JPL will manage Aquarius through its commissioning phase and archive mission data. Goddard will
manage Aquarius mission operations and process science data. NASA's Launch Services Program at
the agency's Kennedy Space Center in Florida is managing the launch.

CONAE is providing the SAC-D spacecraft, an optical camera, a thermal camera in collaboration
with Canada, a microwave radiometer,; sensors from various Argentine institutions and the mission
operations center there. France and Italy are contributing instruments.

For more information about Aquarius/SAC-D, visit: http://www.nasa.gov/aquarius and
http://www.conae.gov.ar/eng/principal.html .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

-end-

Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov

Steve Cole 202-358-0918
NASA Headquarters, Washington
Stephen.e.cole@nasa.gov

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