The tropical Pacific Ocean remains in the grips of a cool La Niña, as shown
by new data of sea-level heights from mid-October of 2007, collected by the
U.S-French Jason altimetric satellite. This La Niña, which has slowly
strengthened for the past nine months, is indicated by the blue area in the
center of the image along the equator. Blue indicates lower than normal sea
level (cold water).
The new image is available at http://www.nasa.gov/vision/earth/lookingatearth/20071106.html.
"After eight very dry years on the Colorado River watershed and a
record-breaking dry winter in Southern California in 2006-2007, the situation
in the American Southwest is dangerously dry," said oceanographer Bill
Patzert of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This La Niña
could deepen the drought in the already parched Southwest and Southeast
United States."
Patzert and other scientists say La Niña contributed to the conditions that
fueled Southern California's recent deadly wildfires.
A La Niña situation often follows an El Niño episode and is essentially the
opposite of an El Niño condition. During a La Niña, trade winds are stronger
than normal, and the cold water that normally exists along the coast of South
America extends to the central equatorial Pacific. A La Niña changes global
weather patterns and is associated with less moisture in the air, resulting in
less rain along the coasts of North and South America, the equator and in
the far Western Pacific. Jason will continue to track this change in Pacific
climate.
This image of the Pacific Ocean was produced using sea-surface height
measurements taken by Jason. The image is based on the average of 10
days of data centered on October 16, 2007, compared to the long-term
average of observations from 1993 through 2005. In the image, places
where the Pacific sea surface height is higher (warmer) than normal are
yellow and red, and places where the sea surface is lower (cooler) than
normal are blue and purple. Green shows where conditions are near normal.
Sea-surface height is an indicator of the heat content of the upper ocean.
The comings and goings of El Niño and La Niña are part of a longer evolving
state of global climate, of which sea-surface height is a useful indicator. The
Jason follow-on mission, Ocean Surface Topography Mission/Jason-2, is
scheduled for launch next June and will extend the data record to a span of
two decades.
NASA's Jet Propulsion Laboratory manages the U.S. portion of the
U.S./French Jason mission for NASA's Science Mission Directorate,
Washington, D.C. JPL is a division of the California Institute of
Technology, Pasadena, Calif.
For more information on NASA's ocean surface topography missions, see
http://sealevel.jpl.nasa.gov/ or to view the latest Jason data see
http://sealevel.jpl.nasa.gov/science/jason1-quick-look/.