NASA Voyage Set To Explore Link Between Sea Saltiness And Climate

Sept. 05, 2012

Steve Cole
Headquarters, Washington
202-358-0918
stephen.e.cole@nasa.gov


RELEASE: 12-305

NASA VOYAGE SET TO EXPLORE LINK BETWEEN SEA SALTINESS AND CLIMATE

WASHINGTON -- A NASA-sponsored expedition is set to sail to the North
Atlantic's saltiest spot to get a detailed, 3-D picture of how salt
content fluctuates in the ocean's upper layers and how these
variations are related to shifts in rainfall patterns around the
planet.

The research voyage is part of a multi-year mission, dubbed the
Salinity Processes in the Upper Ocean Regional Study (SPURS), which
will deploy multiple instruments in different regions of the ocean.
The new data also will help calibrate the salinity measurements
NASA's Aquarius instrument has been collecting from space since
August 2011.

SPURS scientists aboard the research vessel Knorr leave Sept. 6 from
the Woods Hole Oceanographic Institution in Woods Hole, Mass., and
head toward a spot known as the Atlantic surface salinity maximum,
located halfway between the Bahamas and the western coast of North
Africa. The expedition also is supported by the National Oceanic and
Atmospheric Administration and the National Science Foundation.

The researchers will spend about three weeks on site deploying
instruments and taking salinity, temperature and other measurements,
before sailing to the Azores to complete the voyage on Oct. 9.

They will return with new data to aid in understanding one of the most
worrisome effects of climate change -- 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, with far-reaching implications for life on Earth.

"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," said
Raymond Schmitt, a physical oceanographer at Woods Hole and principal
investigator for SPURS. "Getting that right is going to involve
understanding the ocean, because the ocean is the source of most of
the water."

Oceanographers believe the ocean retains a better record of changes in
precipitation than land, and translates these changes into variations
in the salt concentration of its surface waters. Scientists studying
the salinity records of the past 50 years say they already see the
footprint of an increase in the speed of the water cycle. The places
in the ocean where evaporation has increased and rain has become
scarcer have turned saltier over time, while the spots that now
receive more rain have become fresher. This acceleration ultimately
may exacerbate droughts and floods around the planet. Some climate
models, however, predict less dramatic changes in the global water
cycle.

"With SPURS we hope to find out why these climate models do not track
our observations of changing salinities," said Eric Lindstrom,
physical oceanography program scientist at NASA Headquarters in
Washington. "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."

To learn more about what drives salinity, the SPURS researchers will
deploy an array of instruments and platforms, including autonomous
gliders, sensor-laden buoys and unmanned underwater vehicles. Some
will be collected before the research vessel heads to the Azores, but
others will remain in place for a year or more, providing scientists
with data on seasonal variations of salinity.

Some of the devices used during SPURS to explore the Atlantic's
saltiest spot 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 smaller fluxes of salt in the waters.
The suite of ocean instruments will complement data from NASA's
salinity-sensing instrument aboard the Aquarius/SAC-D (Satelite de
Aplicaciones Cientificas-D) observatory, and be integrated into
real-time computer models that will help guide researchers to the
most interesting phenomena in the cruise area.

"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," said David Fratantoni, a physical
oceanographer with Woods Hole and a member of the SPURS expedition.
"But we're also trying to see variations in the ocean that can't be
resolved by current satellite technology."

The 2012 SPURS measurements in the North Atlantic will help scientists
understand the behavior of other high-salinity regions around the
world. A second SPURS expedition in 2015 will investigate
low-salinity regions where there is a high input of fresh water, such
as the mouth of a large river or the rainy belts near the equator.

For more information on the SPURS expedition, visit:

http://spurs.jpl.nasa.gov/SPURS

For more information on Aquarius, visit:


http://www.nasa.gov/aquarius

Regular blog updates from the SPURS expedition will be posted at:


http://go.nasa.gov/PuyO5q


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