September 5, 2012

NASA To Set Sail And Explore Saltiness Of The Oceans

Lee Rannals for redOrbit.com - Your Universe Online

A new expedition is set to get a better picture of how salt content fluctuates in the ocean's upper layers, and how it shifts rainfall patterns.

The NASA-sponsored expedition called the Salinity Processes in the Upper Ocean Regional Study (SPURS) will provided new data to help calibrate the salinity measurements NASA's Aquarius instrument has been collecting from space since August 2011.

SPURS scientists will hop aboard the vessel Knorr on September 6th from the Woods Hole Oceanographic Institution in Woods Hole, Massachusetts. They will be heading towards a spot known as the Atlantic surface salinity maximum.

The researchers will be spending about three weeks on site deploying instruments and taking salinity, temperature, and other measurements, before setting sail towards Azores to complete the voyage on October 9.

NASA said the team will return with new data to help aid in understanding the acceleration of Earth's water cycle. As global temperatures go up, evaporation increases, altering the frequency, strength and distribution of rainfall around the planet.

"What if the drought in the U.S. Midwest became permanent? To understand whether that could happen we must understand the water cycle and how it will change as the climate continues to warm," Raymond Schmitt, a physical oceanographer at Woods Hole and principal investigator for SPURS, said in a statement. "Getting that right is going to involve understanding the ocean, because the ocean is the source of most of the water."

The scientists believe the ocean can give a better record of changes in precipitation than land, and can translate these changes in variations in the salt concentrations of its surface waters.

Scientists say they already see the footprint of an increase in the speed of the water cycle based on salinity records for the past 50 years. The places in the ocean where evaporation increased and rain has become scarcer may have turned saltier over time, while the spots that now receive more rain become fresher.

This acceleration may exacerbate droughts and floods around the planet, according to NASA.

"With SPURS we hope to find out why these climate models do not track our observations of changing salinities," Eric Lindstrom, physical oceanography program scientist at NASA Headquarters in Washington, said in a press release. "We will investigate to what extent the observed salinity trends are a signature of a change in evaporation and precipitation over the ocean versus the ocean's own processes, such as the mixing of salty surface waters with deeper and fresher waters or the sideways transport of salt."

The SPURS scientists will be deploying an array of instruments and platforms, including autonomous gliders, sensor-laden buoys and unmanned underwater vehicles. Some of the instruments will be collected before the research heads to the Azores, while other will remain in place for a year or more.

Some of the devices used during the expedition will focus on the outer edges of the study area, traveling for hundreds of miles and studying the broadest salinity features.

Other instruments will explore smaller areas nested inside the research site, focusing on small fluxes of salt in the waters.

"We'll be able to look at lots of different scales of salinity variability in the ocean, some of which can be seen from space, from a sensor like Aquarius," David Fratantoni, a physical oceanographer with Woods Hole and a member of the SPURS expedition, said in a press release. "But we're also trying to see variations in the ocean that can't be resolved by current satellite technology."

A second SPURS expedition is set for 2015, which will investigate low-salinity regions where there is a higher input of fresh water.