In early 2006, a weak La Niña event kept the temperatures in the Pacific
Ocean along the equator a little cooler than normal. Atlantic Ocean
hurricane forecasters were keeping an eye on the Pacific because La
Niña events and the large-scale atmospheric changes that often go along
with them can have a long-distance effect on hurricane formation in the
Atlantic Ocean. But by April 2006, the La Niña had all but faded. The latest
remote-sensing data from the NASA/French Jason satellite show near-normal
conditions across the equatorial Pacific Ocean.
This image shows Jason observations of sea surface height collected over
a 10-day period centered on May 24, 2006. The height of the water relates
to the temperature of the water, an indicator of the changing amount of heat
stored in the ocean. As the ocean warms, its level rises; as it cools, its level
falls. Yellow and red areas indicate where the waters are relatively warmer
and have expanded above normal sea level. Green areas, which dominate
the image, indicate near-normal sea level. Blue and purple areas show where
the waters are relatively colder, and the sea level is lower than normal.
The Jason satellite carries a dual-frequency radar altimeter. This instrument
beams microwave pulses downward toward the Earth at frequencies of 13.6
and 5.3 Gigahertz. To determine the ocean's height, the instrument precisely
measures the time it takes for the microwave pulses to bounce off the surface
and return to the spacecraft. This measure, multiplied by the speed of light,
gives the range from the satellite to the ocean surface.
The Jason mission is a collaboration between the United States and France,
managed jointly by NASA's Jet Propulsion Laboratory and the Centre
National d'Etudes Spatiales (CNES). NASA's research on Earth's oceans
using Jason and other space-based capabilities is conducted as a part of
its Science Mission Directorate, to better understand and protect our home
planet. For more information, visit the Jason website.
