Climate forecasts get salty with NASA's Aquarius

What are current climate models missing? A dash of salt. NASA prepares to launch a satellite that dives into the relationship between ocean circulation, salinity and the weather.
Written by Melissa Mahony, Contributor

The Age of Aquarius commences this week, revealing the deep secrets of water signs. Aquarians, calm down. This isn't astrology but climate science. On Thursday, NASA plans to launch Aquarius, a satellite that will measure salt concentrations in our oceans from space. From 408 miles above Earth, NASA and CONAE (Argentina's space agency) hope to suss out interactions between ocean circulation and precipitation, information that could help fill in some gaps for climate models.

The relationship between the sea and climate is a salty one. In a state of constant flux, the upper layer of the ocean continuously transfers heat and freshwater with the air above it. Freshwater moves in via stormy weather, melting glaciers, and rivers and moves out through evaporation and big freezes. Every week for the next three years, Aquarius will keep close account of these exchanges within the water cycle.

This is no easy task considering sea surface salinity varies just between 32 and 37 parts per thousand. Salt comprises just around 3.5 percent of the world's oceans. But just a dash here and a dash there goes a long way. Cooler, saltier water sinks, helping to drive circulation at the lower levels of the sea. These deep ocean currents, such the Gulf Stream, transfer heat across the globe and influence climate.

According to NASA, Aquarius will be able to detect changes in salinity as tiny as about one-eighth of a teaspoon of salt in a gallon of water.

Researchers have typically employed buoys, boats and aircraft to do this. Now over the ice-free surfaces of the ocean, Aquarius will pick up on the seawater's weak microwave radiation to determine an area's salt concentrations. NASA will then compare data with ARGO, a network of buoys that takes only deep-sea salinity measurements (right), and the European Space Agency's SMOS satellite that launched in 2009.

Gary Lagerloef, the mission's lead investigator from the Earth and Space Research laboratory in Seattle, in a statement:

We'll see the ocean in a whole different light. When the first Earth science satellites launched in the 1970s, we saw ocean eddies for the first time and got our first glimpse of the tremendous turbulence of the ocean. With Aquarius, we're going to see things we don't currently see. It's as though the blinders will be removed from our eyes.

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Images: NASA and NASA/Goddard Space Flight Center Scientific Visualization Studio

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