NASA Mission to be Crystal Ball into Oceans' Future, Mirror to the Past

Feature July 8, 2008

NASA Mission to be Crystal Ball into Oceans' Future, Mirror to the Past

Imagine the lives that could be saved from flash floods and drought, the millions of dollars
in fuel costs that could be avoided for fishing vessels, and the homes that could be spared
from the effects of coastline erosion if only scientists could more accurately predict the
dynamics of Earth's often unpredictable oceans. Armed with increasingly more accurate
forecasts, weather services in countries across the globe are improving time-sensitive
warnings of cyclones, flooding and high sea winds, as well as information about when it's
safe to scuba dive, sail, or fish 48 kilometers (30 miles) or more beyond coastlines.

NASA and several other international organizations have joined forces to launch into space
a "crystal ball" to give scientists an extended satellite data record. The data can be used to
improve ocean forecasting and to test the accuracy of climate and weather models using
knowledge of past ocean conditions.

The newly-launched Ocean Surface Topography Mission/Jason 2 is made up of next-
generation, state-of-the-art, satellite-based instruments that will provide a global view of
Earth's sea surface height every 10 days. Scientists will use these data to create complex
simulations of how ocean currents, tides and eddies might behave. Similarly, the data will
also allow scientists to "hindcast" -- that is, to test how accurate the simulations of past
ocean forecasts were.

"To borrow from an old saying, 'it's the motion of the ocean' that is of most interest to us as
scientists, and our ability to forecast it and learn lessons from it," said one of the mission's
science team members, Robert Leben, an associate research professor at the University of
Colorado in Boulder. "The further we can look into the past with the record of ocean
measurements, the better we can predict future events. That is to say, if one day we can look
back at a 20- or 30-year data record, we can more accurately say what will happen in the
next 10 or 15 years because we will have a data record that indicates trends or correlations
that lead to specific or expected outcomes. OSTM/Jason 2 is going to add to knowledge
we've gained from the Topex/Poseidon and Jason 1 missions and put us closer to this goal."

To create the simulations, also called models, that predict ocean behavior, scientists
combine information about factors such as wind speed, wave height, sea level pressure,
temperature and air pressure with data gathered by satellite altimeters that measure the
height of the oceans' surface (more commonly known as sea level). Radar altimeters, like
those on OSTM/Jason 2, measure sea level by sending a radar pulse to the sea surface and
clocking the time it takes for the signal to reflect back. All these data are fed into a
computer program, allowing scientists to see into the future or to gain further insight from
simulations of the past when hindcasting.

OSTM/Jason 2 is slated to orbit Earth and collect this important data set for at least three to
five years. It will provide scientists with significantly more data to test their models, and
extend the record of information available about ocean circulation and how the ocean affects
global climate. During the mission's lifetime, scientists hope to add to what they currently
understand about weather phenomena like El Nino and La Nina. During an El Nino, the
eastern Pacific Ocean temperatures near the equator are warmer than normal, while during La
Nina the same waters are colder than normal. These fluctuations in the Pacific Ocean
temperatures can wreak havoc on climate conditions around the Pacific and beyond, leading
to increased rainfall or drought.

"A longer period of data from the OSTM/Jason 2 mission can tell scientists more about how
El Nino and La Nina are coupled not only to seasonal or yearly changes but to decade-to-
decade oscillations of the Pacific Ocean," said Leben. "Owing to data from the mission's
forerunner Topex/Poseidon and Jason 1 missions, scientists have already determined that
decadal fluctuations in the Pacific enhance the frequency and intensity of shorter-term ocean
events such as El Nino and La Nina. Just think of what more we'll learn as we collect future
data from OSTM/Jason 2."

Knowing more about the oceans' behavior, including what El Nino and La Nina climate
conditions may bring, will improve our quality of life and benefit industry. "For example,
forecasts of ocean currents can predict the oceans' salt balance, which can be used to study the
global water cycle," said science team member Yi Chao, a satellite oceanographer at NASA's
Jet Propulsion Laboratory in Pasadena, Calif. Water evaporates from the ocean surface, and
water from rivers and land-runoff cycle back into the ocean, so more precise forecasts of these
movements will boost our knowledge of and ability to manage our most precious natural
resource. This mission can help us determine the role of ocean circulation in completing the
global water cycle."

"On the commercial front, offshore industries such as oil and gas exploration and production
require accurate information about ocean circulation to minimize the impacts from strong
currents and eddies," said Leben. "Search and rescue officials, marine operators, recreational
boaters, and marine animal researchers all benefit from increasingly more accessible near real-
time data."

"The Topex/Poseidon and Jason 1 missions got us off to a great start," said Chao. "When the
two missions operated together in tandem, they doubled the coverage area and sharpness of
the resolution of the sea level data so that we could 'see' more detail. This higher resolution is
critical for extending the global sea level data into coastal zones, which of course are regions
of great societal importance. OSTM/Jason 2 will provide another opportunity for a tandem
mission with Jason-1."

Leben pointed out that with this new mission, the focus moves from research objectives to
practical ways to apply the data that benefit society in tangible and essential ways.

For more information on OSTM/Jason 2, visit: http://www.nasa.gov/ostm .

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