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Contact: Diane Ainsworth, Media Relations Office, 818/354-0850
Dr. William Patzert, interviews and technical
IMAGE ADVISORYNovember 29, 1999
MILD LA NINA CONDITIONS DEVELOPING, SATELLITE DATA SHOW
Unusually warm ocean temperatures off Asia and cool waters
in the eastern and equatorial Pacific are signaling La Nina's
mild return, according to the latest sea-surface heights observed
by the joint NASA-French space agency's TOPEX/Poseidon satellite.
Lower than normal sea-surface heights in the eastern North
Pacific and abnormally high sea-surface heights in the western
and mid-latitude Pacific are expected to drive storms coming out
of the Pacific this winter, the mission data indicate. Those
conditions will most likely steer storms north into the Pacific
Northwest and keep the southwestern United States dryer than
The latest measurements, processed after a 10-day data cycle
November 4-13 at NASA's Jet Propulsion Laboratory, Pasadena, CA,
are available at http://www.jpl.nasa.gov/elnino . Sea-surface
height is shown relative to normal (green) and reveals cooler
water (blue and purple) measuring between 8 and 24 centimeters (3
to 9 inches) lower than average in the eastern North Pacific,
from the Gulf of Alaska to central Alaska, and along the equator.
Unusual conditions persist in the western and mid-latitude
Pacific Ocean as well, with higher than average sea-surface
heights (red and white) of between 8 and 24 centimeters (3 to 9
inches). These areas of increased sea-surface height and
unusually warm water were present last year, but the increase in
height has surpassed last year's measurements.
The TOPEX/Poseidon satellite's measurements over the last
seven and a half years have provided scientists with a
comprehensive record of the 1997-1999 El Nino/La Nina climate
pattern by measuring changing sea-surface heights to within 4
centimeters (1.5 inches) precision.
The U.S./French mission is managed by the Jet Propulsion
Laboratory for NASA's Earth Sciences Enterprise, Washington, DC.
JPL is a division of the California Institute of Technology,