Featured Research

from universities, journals, and other organizations

Recent Shifts In Pacific Winds May Support El Nino Formation

Date:
March 18, 2002
Source:
NASA/Jet Propulsion Laboratory
Summary:
Wind data for the Pacific Ocean obtained by NASA's Quick Scatterometer spacecraft-also know as Quikscat-are documenting episodes of reversed trade winds that are responsible for unseasonable cyclone conditions in the northwest and southwest Pacific, and which may be a precursor of a future El Niño.

Wind data for the Pacific Ocean obtained by NASA's Quick Scatterometer spacecraft-also know as Quikscat-are documenting episodes of reversed trade winds that are responsible for unseasonable cyclone conditions in the northwest and southwest Pacific, and which may be a precursor of a future El Niño.

A research team led by Dr. W. Timothy Liu, a senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., used wind speed and direction data from Quikscat to detect a shift in the trade winds on February 25. The winds shifted from their normal easterly direction to a westerly direction, blowing from Indonesia toward the Americas along the equator. This trade wind shift, which lasted for about a week, contributed to the spawning of twin cyclones--Super Typhoon Mitag, which threatened the Philippines; and Tropical Cyclone Des, which passed through New Caledonia.

"In addition to unusual cyclonic activity, such trade wind reversals typically trigger Kelvin waves of warm water, which can be an early indicator of future El Nino conditions," said Liu. "During periods of reversed trade winds, which typically last from a few days to a week or more, equatorial westerly winds generate a counterclockwise vortex in the northern hemisphere and a clockwise vortex in the southern hemisphere. Once spawned, the resulting Kelvin waves may travel across the Pacific and reach the coastline of the Americas in approximately one to two months, warming the waters of the eastern Pacific and creating El Niño conditions when the effects are accumulated."

Sustained Kelvin wave activity could have a major impact on global weather patterns according to JPL oceanographer Dr. William Patzert. "If trade wind patterns continue to experience reversals through the spring and summer, the resulting strong, warm Kelvin waves will cross the Pacific like a conveyor belt, depositing warm water near South America where the ocean is normally cold," he said. "Such a 'warm pool' could alter weather all over the planet, with rains that would normally soak the western Pacific shifting toward the Americas, and places such as Indonesia and India becoming drier. We're really in a 'wait and see' situation at this point."

A similar westerly wind flow and twin cyclones were documented by Liu and his team using Quikscat data last December. The wind reversal at that time, which lasted 10 days, triggered a Kelvin wave that just recently reached South America, as revealed by NASA's Topex/Poseidon satellite.

The Quikscat images are available at:

http://www.earthobservatory.nasa.gov/Newsroom/NewImages/images.php3 .

More details of the two westerly winds events can be found at:

http://airsea-www.jpl.nasa.gov/enso .

Launched June 19, 1999, the Quikscat spacecraft operates in a Sun-synchronous, 800-kilometer (497-mile) near-polar orbit, circling Earth every 100 minutes, taking approximately 400,000 measurements over 93 percent of Earth's surface every day.

In recent years, data from JPL's Quikscat scatterometer have proven useful in improving forecasts of extreme wind events, such as hurricanes, and in monitoring longer-term climatic effects such as El Niño. Quickscat's SeaWinds scatterometer instrument is a specialized microwave radar that continuously measures both the speed and direction of winds near the ocean surface in all weather conditions.

JPL manages Quikscat for NASA's Office of Earth Science, Washington, D.C. JPL also built the scatterometer instrument and provides ground science processing systems. NASA's Goddard Space Flight Center, Greenbelt, Md., managed development of the satellite, designed and built by Ball Aerospace & Technologies Corp., Boulder, Colo.

More information on Quikscat is available at:

http://winds.jpl.nasa.gov/missions/quikscat/quikindex.html .

The U.S.-French Topex/Poseidon mission has been making precise measurements of ocean surface topography since 1992. These data are used to map ocean currents, improve the understanding of ocean circulation, measure global sea level change and improve global climate forecasts. Topex/Poseidon's ability to measure sea-surface height has made it an invaluable tool for studying ocean events such as El Niño, its little sister La Niña and the much larger and longer-lasting ocean event called the Pacific Decadal Oscillation. Topex/Poseidon is managed by JPL for NASA's Earth Science Enterprise, Washington, D.C.

More information on Topex/Poseidon is available at:

http://topex-www.jpl.nasa.gov/ .

NASA's Earth Science Enterprise is a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

JPL is a division of the California Institute of Technology in Pasadena.


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Jet Propulsion Laboratory. "Recent Shifts In Pacific Winds May Support El Nino Formation." ScienceDaily. ScienceDaily, 18 March 2002. <www.sciencedaily.com/releases/2002/03/020315072307.htm>.
NASA/Jet Propulsion Laboratory. (2002, March 18). Recent Shifts In Pacific Winds May Support El Nino Formation. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2002/03/020315072307.htm
NASA/Jet Propulsion Laboratory. "Recent Shifts In Pacific Winds May Support El Nino Formation." ScienceDaily. www.sciencedaily.com/releases/2002/03/020315072307.htm (accessed July 31, 2014).

Share This




More Earth & Climate News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) — Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) — With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Big Waves In Arctic Ocean Threaten Polar Ice

Big Waves In Arctic Ocean Threaten Polar Ice

Newsy (July 30, 2014) — Big waves in parts of the Arctic Ocean are unprecedented, mainly because they used to be covered in ice. Video provided by Newsy
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) — Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins