(-06-) Date: 24 Jan 1995
Subject: Topex Confirms El Nino is Back
From: NasaNews
TOPEX/POSEIDON CONFIRMS EL NINO IS BACK AND STRONGER THAN IN 1993
The El Nino phenomenon is back and is getting stronger, according to
scientists studying data from the ocean-observing TOPEX/POSEIDON
satellite.
El Nino is a climatic event that can bring devastating weather to
several parts of the world, including the recent heavy rains and
flooding in California, and the warmer than normal winter in the
eastern United States.
"The satellite has observed high sea-surface elevation, which reflects
an excessive amount of unusually warm water in the upper ocean," said
Dr. Lee-Lveng Fu, JPL TOPEX/POSEIDON project scientist at NASA's Jet
Propulsion Laboratory, Pasadena, CA. "The associated excess of heat
creates high sea-surface temperatures, which affect the weather
worldwide by heating the atmosphere and altering the atmospheric jet
streams."
Jet streams are high-level winds, five to ten miles above the Earth's
surface, created when warm and cold air masses meet. Shifts in the
location of jet streams change temperatures and precipitation zones at
the surface.
El Nino begins when the westward trade winds weaken and a large warm
water mass, called a Kelvin wave, is allowed to move eastward along the
equator in the Pacific Ocean. Data from the radar altimeter onboard
TOPEX/POSEIDON, recorded from October through December 1994, reveal a
new Kelvin wave moving toward the western coast of South America.
"This wave is currently occupying most of the tropical Pacific Ocean.
It will take another month or two before the wave disperses. Compared
to the El Nino condition of the winter of 1992-93, the present one
appears somewhat stronger and might have stronger and longer lasting
effects," Fu said.
TOPEX/POSEIDON, a joint program of NASA and the Centre Nationale
d'Etudes Spatiales, the French space agency, uses a radar altimeter to
precisely measure sea-surface height. Scientists use the
TOPEX/POSEIDON data to produce global maps of ocean circulation.
Launched Aug. 10, 1992, the satellite has completed two and a half
years of its three-year prime mission and has provided oceanographers
with unprecedented global sea level measurements that are accurate to
better than 2 inches (5 centimeters).
"The global sea-surface elevation information provided by
TOPEX/POSEIDON is unique because it is related to the amount of heat
stored in the upper ocean, which is important for long-range weather
forecasting. The speed and direction of ocean currents also can be
determined from the elevation information, providing another piece of
critical information about the ocean, which is the key to climate
change," Fu continued.
TOPEX/POSEIDON is part of NASA's Mission to Planet Earth, a
coordinated, long-term research program to study the Earth's global
environment. TOPEX/POSEIDON's sea-surface height data are essential
to understanding the role oceans play in regulating global climate, one
of the least understood areas of climate research. TOPEX/POSEIDON will
provide the first comprehensive, consistent measurements of the
circulations of the ocean. The Jet Propulsion Laboratory manages the
TOPEX/POSEIDON mission for NASA.
NOTE: the following images are available from ftp.jpl.nasa.gov:
/images/browse/elnino2.gif JPL photoproduct P-45140 (90k)
/images/hi-res/p45140.tif Full-res version (11140k)
/images/hi-res/p45140.txt Caption for P-45140.tif (3k)
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- T o d d E. V a n H o o s e a r -
``'''vanhoose@lalaland.cl.msu.edu - vanhoose@msu.edu - vanhoose@lalaland.cl.msu.edu
(._.) Michigan State University - East Lansing, MI USA
(_) Computer Laboratory - Department of Communication
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