Brian Dunbar
Headquarters, Washington, DC                September 22, 1995
(Phone:  202/358-1547)

Ernie Shannon
Goddard Space Flight Center, Greenbelt, MD
(Phone: 301/286-6256)


RELEASE:  95-159

SCIENTISTS SAY EL NINO CAN NOW BE PREDICTED A YEAR IN ADVANCE
 
      Recent advances in computer models and how they use 
ocean data now allow predictions of El Nino -- a dramatic 
climate shift that can affect weather and economies worldwide 
-- to be made more than a year before the event, new NASA, 
NOAA and university research indicates.

      "Certain aspects of El Nino, such as equatorial Pacific 
sea-surface temperatures and related changes in precipitation 
patterns can now be predicted with confidence more than one 
year in advance," said Dr. Antonio Busalacchi of NASA's 
Goddard Space Flight Center, Greenbelt, MD.

      The new study used data from the ten-year Tropical Ocean 
Global Atmosphere (TOGA) project, an international research 
program that studied how Earth's oceans and atmosphere affect 
one another.  The team's paper will be published today in the 
journal "Science."  Busalacchi's co-authors are Dr. Dake Chen, 
University of Rhode Island, and Dr. Stephen Zebiak and Dr. 
Mark Cane of Columbia University's Lamont Doherty Earth 
Observatory, Palisades, NY.

      TOGA has successfully completed its decadal mission and 
the world legacy of the Topical Atmosphere Ocean array and all 
the research infrastructure is in place.  New programs will 
continue to move this research into operational application 
mode.  In November, an "International Forum on Forecasting El 
Nino" will be held in Washington, DC.  The forum will launch 
an International Research Institute for climate prediction.

      El Nino, which can occur every two to seven years, 
originates in the tropical Pacific ocean and causes global-
scale disruptions in normal weather patterns.  When an El Nino 
occurs, torrential rainfall and flooding is common along the 
coasts of Ecuador, Peru and southeast Brazil. At the same 
time, Australia, Indonesia, northeast Brazil and southeast 
Africa experience extreme drought and famine conditions.

      The impact of El Nino on the continental United States 
is less direct than in the tropics, but still distinct.  
Increased precipitation over the Gulf Coast states and warmer 
winter temperatures over the north-central tier of Gulf Coast 
states are common, with important implications for the 
agricultural sector of the economy.

     A common indicator of El Nino occurs when the warmest 
water of the global ocean shifts from the International 
Dateline in the Pacific eastward by 3,100 miles (5,000 
kilometers), increasing sea-surface temperature by 4 to 7 
degrees Fahrenheit (2 to 4 degrees Centigrade).  This eastward 
migration of a heat source critical to the atmosphere changes 
global weather patterns, including precipitation and 
temperature, far beyond the equatorial Pacific.

     Forecasts of El Nino have commonly started with 
scientists introducing ocean-wind data models into a computer 
model of the ocean, which is then used separately to "force" a 
model of the atmosphere.  At that point the two models are 
joined, and the likelihood of an El Nino is forecast.  The new 
approach mathematically joins the models before introducing 
the data.  Since the real ocean and atmosphere are closely 
linked, this approach yields results that lead to a more 
accurate forecast.

      "That's the breakthrough," said  Busalacchi.  "This is 
the first time data are being assimilated into a coupled 
model, and that's what gives us this expanded forecasting 
capability.

      "Developing and developed countries are getting this 
data through one-on-one contacts and through NOAA.  They're 
beginning to use these forecasts to adapt to these events and 
to mitigate their dangers.  Advances such as these suggest 
that it is time to implement a process to issue El Nino 
forecasts on a routine basis, so that the affected countries 
may benefit from this information," Busalacchi said. 

      This kind of computer model, and its use to predict 
changes in the Earth's environment, is the heart of NASA's 
Mission to Planet Earth and the U.S. Global Change Research 
Program.  A long-term, coordinated research program, Mission 
to Planet Earth is designed to provide near-term benefits.  
The program provides improved forecasting of economically 
threatening climate changes such as El Nino, with improved 
understanding of the Earth's climate and how it changes.

       Mission to Planet Earth combines surface measurements 
and computer models with space-based measurements to provide a 
view of the Earth's global environment.  Busalacchi's model, 
for example, will increase in importance when the NASA 
Scatterometer begins returning worldwide data on sea-surface 
winds.  The instrument is scheduled for launch in August 1996 
aboard a Japanese satellite.

                        - end -

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