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June 1998
Science

La Niña summit set for July

As the 1997-98 El Niño limps along toward its expected demise, popular interest (fueled by scientists' statements) is swinging toward La Niña. It's too early to tell whether this intensified cooling of the eastern tropical Pacific will arrive this winter, but an in-depth discussion of La Niña will hit Boulder this summer.

NCAR is playing host 15-17 July to the world's first summit devoted to El Niño's less-studied counterpart. Review of the Causes and Consequences of Cold Events: A La Niña Summit is being organized by Mickey Glantz (ESIG) with support from the United Nations University (UNU), based in Tokyo. The Mesa Lab summit will draw a number of the nation's top researchers on La Niña and El Niño from universities and government agencies.

"To many people, anything that's not El Niño is considered normal," notes Mickey. La Niña is an enhancement of the normal sea-surface temperature pattern across the tropical Pacific (warm surface waters in the west and central Pacific, cool waters to the east). During La Niña, the easterly trade winds strengthen, cold upwelling off Peru and Ecuador intensifies, and sea-surface temperatures there drop up to 7degreesF below normal.

Unnamed until the mid-1980s, and sometimes referred to as El Viejo (Spanish for "the old man"), La Niña ("the girl") has received less attention than El Niño. However, La Niña's effects--for example, an increased hurricane threat in the Atlantic Ocean and Gulf of Mexico--can't be ignored. Another reason for the relative lack of attention: in the past 20 years there have been only three La Niñas, compared to seven El Niños, sparking some debate over whether global climate change might be tweaking the Pacific tropics toward a semipermanent warm state. (See the UCAR Quarterly feature.)

In order to stimulate dialogue at the summit, Mickey is planning a "roll-up-your-sleeves" agenda with lots of interaction. The goal is to identify what is known with some degree of reliability about La Niña and its societal and environmental impacts. A workshop report will be released afterward.

The summit is the first project in a "usable science" collaboration supported by UNU and aimed at helping Pacific Rim countries respond to El Niño and La Niña risks. Mickey is the project coordinator.

As for the El Niño now winding down, Mickey has compiled a summary of the predictions issued by 19 dynamical and statistical models between March 1996 and September 1997. Among the adjectives used to describe the El Niño then approaching: "strong," "weak," "quite weak," "quite strong," "warmish," "dropping to normal." Some models had caught on to the impending event by early 1997, while at least one missed it even as it was occurring. Ocean buoy data made it clear by summer 1997 that a major El Niño was in the works, and well-publicized forecasts created a media frenzy. Still, says Mickey, this event "developed earlier than expected, stayed strong longer than expected, grew bigger than expected, and was hotter than expected."

On the Web

Workshop: A La Niña Summit

Mickey's article "The El Niño Olympics, or
The Search for the El Niño of the Century":
Fragilecologies

A new name for UNAVCO

To reflect its broadening research agenda, UOP's UNAVCO program has been renamed the GPS Science and Technology program (GST). Stick Ware remains the program director.

When UNAVCO joined UCAR in 1991, its primary role was maintaining a fleet of Global Positioning System receivers for universities to use in tracking crustal motions and other geophysical phenomena. Since then, GPS technology has been expanded to a number of atmospheric applications. The COSMIC program (Constellation Observing System for Meteorology, Ionosphere, and Climate) was spun off from UNAVCO last winter as a separate UOP program.

The UNAVCO facility and its pool of GPS receivers will continue as an activity within GST managed by Wayne Shiver. GST also includes

GPS Research and GPS/MET--the groups that helped

pioneer ground and space-based atmospheric sensing with GPS. Chris Rocken manages these two groups.

"GST is focused on cross-disciplinary science applications. With GPS, we can forge a strong partnership between the solid-earth and atmospheric sciences," says Stick.

On the Web

GPS Science & Technology Program


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Edited by Bob Henson, bhenson@ucar.edu

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