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Sea surface salinity measurements taken by NASA's Aquarius instrument.  Click here for a video of the Aquarius mission. Visit the NASA Aquarius mission gallery to find podcasts, video, and images. 

Studying the ocean is useful when investigating climate change on planet Earth. The ocean system plays a primary role in climate by absorbing heat and transporting it from the equator to the poles. Many issues come into play, however, when looking at melting ice at the poles, increasing ocean acidification and rising sea levels. A key question is whether the global ocean conveyer belt will be affected by the events occuring in the ocean system. Based on this question, a closer look at ocean salinity is justified.

The salinity of the ocean plays key roles in the global hydrological cycle, impacting ocean circulation and climate. Ocean water contains a high concentration of salt. The salt comes from a variety of sources to include evaporation, dissolved rocks, volcanoes and hydrothermal vents. These processes tend to increase water’s salinity. The addition of water from a fresh water river, rain, snow and the melting of ice, in turn, reduce salinity. 

Scientists are interested in Sea Surface Salinity (SSS) because of its impact on the water cycle. Ocean salinity varies from place to place and usually ranges from 32 to 37 psu, a unit that expresses the amount of salt dissolved in water. Some latitudes of the ocean are "rainy" while others are arid and "desert-like." The latitudes with high precipitation have low SSS, and those with high evaporation have high SSS, because salt is left behind after the water evaporates. 

For the first time, scientists are able to measure SSS globally using NASA's Aquarius instrument. This is extremely important because until now data were mostly collected by ships and instruments on buoys. With Aquarius, NASA scientists can monitor the relationship between evaporation and precipitation around the world.

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