Freighters, cruise lines, marine rescuers and coastal
managers are among those who could benefit from prototype
three-dimensional, three-day ocean condition forecasts created
with the assistance of NASA satellite data, computer models and
on-site ocean measurements.
Scientists hope to forecast ocean conditions several days
ahead, much like regional weather forecasts broadcast on
television news. “It’s a three-dimensional look at the ocean,
from the surface to the ocean bottom,” said Yi Chao of NASA’s
Jet Propulsion Laboratory (JPL), Pasadena, Calif., lead
scientist on the project. Chao and three colleagues presented
their real-time operational forecast system for the Central
California Ocean at the recent Annual Meeting of the American
Meteorological Society (AMS).
The end product from our 3-D ocean model includes temperature,
salinity and current,” Chao said. These are available as text
or binary data, or can be visualized for further analysis.
Seeing the ocean in three dimensions, and knowing how it will
behave from top to bottom, will save fuel costs for large
shippers by steering away from choppy waters, or moving with
the current. The data will also help Coast Guard rescuers, as
they would be able to determine which direction people stranded
in the water would drift. Several satellite measurements
provide input into the forecast system, including near-real
time wind data from the Quikscat instrument on NASA’s SeaWinds
satellite; ocean height, including waves, measured from NASA’s
Topex/Poseidon and Jason satellites; sea surface temperatures
measured by the National Oceanic and Atmospheric
Administration’s (NOAA) Geostationary Operational Environmental
Satellites Advanced Very High Resolution Radiometer instrument.
Aircraft data from the Office of Naval Research is used on
cloudy days, when satellites cannot see the ocean surface. A
variety of sensors, such as sea gliders that can dive from the
ocean surface to several hundred meters depth, ships, and
autonomous underwater vehicles, provide ocean water temperature
and salinity data. Meters measure ocean currents, and shore-
based high-frequency radars provide ocean surface current data.
Once these data were input into the forecast system, existing
ocean conditions were simulated in 3-D, within 24 hours behind
real-time, and more accurate three-day forecasts were then
generated in 3-D.
Chao said the NASA 3-D ocean models were useful in planning
daily ocean measurement missions during a field campaign
conducted last summer in Monterey Bay, Calif. Mission
scientists used the forecasts to find interesting areas to
observe, such as where cold water from the ocean bottom came up
to the surface. Wherever the models seemed to generate an
error, more observations were planned, so the forecasts could
be improved.
Data is only available for Monterey Bay, where the prototype
system was first tested. The next test site will stretch along
the coast from San Diego to Baja, Calif. System data are not
yet available for public use. Sixteen institutions are
evaluating the system or providing data. The researchers hope
to eventually issue round-the-clock operational forecasts along
all U.S. coastal areas.
In addition to helping with ocean condition forecasts, NASA
also is interested in studying the coastal ocean to monitor
resources for many purposes including recreation, conservation
and commerce. Satellites provide the high-resolution imagery to
accomplish this task.
NASA and the Office of Naval Research jointly funded this
research. The forecast system exemplifies NASA’s Earth Science
Enterprise Coastal Management national application, where
agency aerospace research and development of science and
technologies are being used with other federal agencies such as
NOAA.
For information about NASA and agency programs on the Internet,
visit:
For more information about 3-D ocean models and images on the
Internet, visit:
http://www.gsfc.nasa.gov/topstory/2004/0113forecastca.html
For a copy of the study abstract from the AMS meeting, visit:
http://ams.confex.com/ams/84Annual/techprogram/paper_73425.htm
