EOSDIS Data Sampler #3 - La Niña Events

Top banner for every page of EOSDIS data sampler number 3

Home -- ENSO Cycle -- ENSO Effects -- Missions -- Data -- Tools -- Site Map

Introduction -- La Niña 1998-2001 -- Local and Web Links

La Niña Events

Introduction

The cold event within the ENSO cycle that is the counterpart to El Niño is known as La Niña, Spanish for "the girl child;" it has also been called El Viejo, "the old man." Both names indicate that it is an event opposite to an El Niño. This sea surface temperature cold anomaly (Pathfinder SST data) (TRMM TMI SST data) in the surface waters of the tropical Pacific Ocean is linked to strange summer weather around the world:

Drier than normal conditions are observed along the west coast of tropical South America and at subtropical latitudes of North America (southern California to Gulf Coast) and South America (southern Brazil to central Argentina) during their respective winter seasons.

During the southern hemisphere summer season, wetter than normal conditions are observed west of the equatorial central Pacific over northern Australia, northern Indonesia, southeastern Africa, and northern Brazil. During the Northern Hemisphere's summer season, the Indian monsoon rainfall tends to be greater than normal, especially in northwest India, and wetter than normal conditions are observed over the Philippines.

La Niña sea surface temperature and elevation

La Niña as seen by TOPEX/Poseidon and NOAA's polar-orbiting environmental satellite (NOAA-14/AVHRR). Above-average sea surface heights are raised, while those lower than normal are lowered. Warm water is orange and red, and cooler-than-normal water is blue.
( NASA/Goddard Space Flight Center Scientific Visualization Studio)

La Niña 1998-2001 (Long La Niña)

Top of Page

The La Niña of 1998-2001 was average in intensity, but long in duration. At its peak, it was associated with a 15- to 20-centimeter deep trough in the central tropical Pacific, and with a 2- to 3-degree Centigrade dip in normal ocean surface temperatures. NASA's Sea-viewing Wide Field-of-View Sensor (SeaWiFS) on the OrbView-2 satellite recorded the largest bloom of microscopic algae ever seen off the coast of Central and South America, (SeaWiFS chlorophyll data) a result of the increased upwelling that carried nutrients into the photic zone. It first appeared in May-June 1998 and persisted into early summer 2000.

In the United States it was marked by

Below normal precipitation in the Southwest, the central and southern sections of the Rockies and Great Plains, and of Florida.

Heavy rainfall and lots of snow in the pacific Northwest and in the northern Intermountain West, and over scattered sections of the North Central States, Ohio Valley, and upper Southeast.

Unusually cold weather in the Northwest and (to a lesser extent) northern California, the northern Intermountain West, and the North Central States.

A slight tendency for higher than normal temperatures in a broad area covering the southern Rockies and Great Plains, the Ohio Valley, the Southeast, and the Mid-Atlantic States.

The La Niña of 1998-2001 was followed by the ENSO-neutral (MODIS SST data) year of 2001-02. However, El Niño conditions developed for 2002-03.

Local Links

Top of Page

Information About ENSO Events

Information About ENSO Effects and Impacts

Disclaimer: NASA offers these suggested sites for additional information regarding La Niña events. Web access is required to reach these sites. Link existence and contents are not under the control of the EOSDIS Science Operations Office.

La Niña Web Sites

Cold ( La Niña) Episodes in the Tropical Pacific: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/cold_impacts.html
Heat Wave and La Niña: http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=569
La Niña: http://earthobservatory.nasa.gov/Library/LaNina/
Why 95-96 winter turned out as it did: http://www.usatoday.com/weather/why96wtr.htm
La Niña readies to steal El Niño's thunder: http://www.sciencenews.org/sn_arc98/7_4_98/fob4.htm
Sea-surface Height on the Rise: http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=1513
Ocean Motion: http://www.jpl.nasa.gov/earth/ocean_motion/el_nino_index.html#tracking
Scientists Say Adios to La Niña: http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=3118
Strong, Long-Lasting La Niña Just Fading Away: http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=3823

Top of Page