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Salt plays an important role

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in our daily lives.  True, salt makes

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our food tastier, but perhaps its most significant role is

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as an ingredient in Earth's climate.

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Measurements of sea surface salinity, or the concentration of salt

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at the ocean's surface, gives scientists vital information on

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global ocean circulation and how fresh water moves between the

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ocean and other reservoirs.  How does water move, you might ask?

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Through the water cycle, the process by which

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water circulates from the ocean, to the atmosphere, to the land, and then back to the

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ocean.  Water on the ocean's surface evaporates,

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can travel as clouds or vapor over land,

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fall as rain or snow, and then work its way back to the

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ocean through rivers, surface runoff, or as icebergs.

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In other words, the ocean plays a major role in the

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water cycle.  In fact, 86% of all global

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evaporation and 78% of global precipitation occurs over

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the ocean.  As the water cycle changes,

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so does salinity!  Ocean salinity is

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affected by the water cycle.  As salt water evaporates

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or freezes, the salt is left behind and salinity

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increases.  But precipitation and runoff

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dilute salt water, decreasing salinity.

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Now, while these changes in salinity may seem insignificant compared to the

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size of the ocean, they make a huge difference in how water

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circulates.  Scientists need a breadth of information

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to understand the ocean's processes.  And that's where

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Aquarius comes in.  The sensor will use advanced technologies to

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give NASA its first space-based measurements of sea surface