The U.S. space agency has launched a satellite that will measure the saltiness of the oceans, in a mission to help scientists gain a better understanding of the world's changing climate.

A Delta 2 rocket carrying the Aquarius satellite observatory blasted off Friday from Vandenberg Air Force Base in California.

NASA says data from Aquarius will provide the “most detailed summary” of conditions of the world's water surfaces. It says ships on trade routes previously conducted the surveys, giving what researchers described as an incomplete picture.

The space agency says with this mission, all the world's water surfaces can be studied routinely for three years from space.

Scientists hope to learn what impact changes in ocean circulation and the salinity of the seawater are having on the globe's changing climate. Experts say the Argentine-built, orbiting observatory can measure ocean salinity with near absolute accuracy.