Aquarius made NASA's first space-based global observations of ocean surface salinity in 2011, flying 657 kilometers (408 miles) above Earth in a sun-synchronous polar orbit that repeated every seven days. The Aquarius/SAC-D mission was developed collaboratively between NASA and Argentina's space agency, Comisión Nacional de Actividades Espaciales (CONAE).
Because ocean surface salinity varies from place to place and over time, scientists are using it to trace the ocean's role in Earth's water cycle. For example, about 86% of global evaporation and 78% of global precipitation occur over the ocean. By measuring changes in ocean surface salinity caused by these processes, as well as changes caused by melting ice and river runoff, Aquarius has provided important new information about how Earth's freshwater moves between the ocean and atmosphere and around the globe. Aquarius has also helped scientists track ocean currents and better understand ocean circulation. Together with temperature, salinity controls the density of seawater, determining whether it sinks or floats.
On June 7, 2015, the SAC-D satellite carrying Aquarius suffered a power supply failure, ending the mission.
dates available: 2011-2015
spatial resolution: 1° (~100 km)
data archive: https://oceanwatch.pifsc.noaa.gov/doc.html#salinity