Aquarius instrument, including 2.5 meter reflector, in the clean room at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Aquarius/SAC-D is an international mission involving NASA and Argentina's space agency, Comisín Nacional de Actividades Espaciales. Aquarius, the primary instrument on the mission, was built jointly by JPL and NASA's Goddard Space Flight Center, Greenbelt, Md. It will provide monthly global maps of how the concentration of dissolved salt (known as salinity) varies on the ocean surface. Salinity is a key tracer for understanding the ocean's role in Earth's water cycle and understanding ocean circulation.

By measuring ocean salinity from space, Aquarius will provide new insights into how the massive natural interplay of freshwater moving among the ocean, atmosphere and sea ice influences Earth's ocean circulation, weather and climate.

For more information on Aquarius, visit http://www.aquarius.nasa.gov.