Featured Research

from universities, journals, and other organizations

More El Niño's And La Niña's May Lead To More Global Rainfall Extremes

Date:
January 17, 2001
Source:
NASA/Goddard Space Flight Center--EOS Project Science Office
Summary:
Researchers at NASA and the University of Maryland, Baltimore County (UMBC), studying changes in tropical precipitation patterns, have noted a higher frequency of El Niños and La Niñas over the last 21 years. In addition, when either of those events occur, the world can expect more months with unusually high or low precipitation with droughts more common than floods over land areas.

Researchers at NASA and the University of Maryland, Baltimore County (UMBC), studying changes in tropical precipitation patterns, have noted a higher frequency of El Niños and La Niñas over the last 21 years. In addition, when either of those events occur, the world can expect more months with unusually high or low precipitation with droughts more common than floods over land areas.

Related Articles


Scott Curtis of UMBC and Robert Adler of NASA/Goddard Space Flight Center are co-authors of a paper titled "The Magnitude and Variability of Global and Regional Precipitation Based on the 21 Year Global Precipitation Climatology Project (GPCP) and 3 Year Tropical Rainfall Measuring Mission (TRMM) Data Sets" being presented January 16 at the 2001 Annual Meeting of the American Meteorological Society in Albuquerque, N.M.

El Niño events occur irregularly at intervals of 2-7 years, although the average is about once every 3-4 years. Curtis said the global precipitation database shows El Niños or La Niñas occurring almost every 2 years throughout the last two decades. These events typically last 12-18 months and are accompanied by swings in the Southern Oscillation, an interannual seesaw in tropical sea level pressure between the eastern and western Pacific. El Niño/Southern Oscillation (ENSO) events are characterized by large changes in precipitation over the tropics, which extend around the globe.

Curtis and Adler used data from the World Climate Research Project's Global Precipitation Climatology Project (GPCP), a database of monthly precipitation around the world, to study global and regional variations in rainfall. They compared the GPCP data to rainfall data from NASA's TRMM satellite over the tropics.

They confirmed that during El Niños, such as the one that occurred during 1997-98, there is an increase in precipitation in the central equatorial Pacific and a decrease over the East Indies. More surprisingly, they noticed that changes in precipitation in the equatorial belt extend in a horseshoe shape toward the polar regions. These patterns depend on the season of the year.

Globally, results showed that during years with El Niño it is wetter over the ocean and drier over the land, compared to "neutral" years with neither El Niño nor La Niña. Research indicates that this decrease in rainfall can be up to 7% over tropical land areas. Curtis found that rainfall over the ocean doesn't change much during a La Niña event compared to neutral periods, but the data does indicate wetter land areas.

Curtis said, "Over the entire 21-year span of the global rainfall database, results indicate an increase in rainfall in the Indian monsoon region and a decrease over central Africa. The change in precipitation over the tropics looks like a combination of El Niño and La Niña, which is not too surprising since we just experienced a strong El Niño in 1997-98 followed by a strong La Niña in 1998-99." Also during the period 1979 to 1999, there has been an increase in rain in the monsoon region around India and a decrease over central Africa.

Curtis cautions that because the data only covers 21 years, which in climatic terms is a very short time, more data is needed before a trend in frequency of El Niños and La Niñas can be seen.

TRMM is a joint U.S.-Japanese mission and part of NASA's Earth Science Enterprise; a long-term research program designed to study the Earth's land, oceans, air, ice and life as a total system. Information and images are available at: http://trmm.gsfc.nasa.gov/.


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center--EOS Project Science Office. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Goddard Space Flight Center--EOS Project Science Office. "More El Niño's And La Niña's May Lead To More Global Rainfall Extremes." ScienceDaily. ScienceDaily, 17 January 2001. <www.sciencedaily.com/releases/2001/01/010117075621.htm>.
NASA/Goddard Space Flight Center--EOS Project Science Office. (2001, January 17). More El Niño's And La Niña's May Lead To More Global Rainfall Extremes. ScienceDaily. Retrieved December 18, 2014 from www.sciencedaily.com/releases/2001/01/010117075621.htm
NASA/Goddard Space Flight Center--EOS Project Science Office. "More El Niño's And La Niña's May Lead To More Global Rainfall Extremes." ScienceDaily. www.sciencedaily.com/releases/2001/01/010117075621.htm (accessed December 18, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Thursday, December 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ivory Trade Boom Swamps Law Efforts

Ivory Trade Boom Swamps Law Efforts

Reuters - Business Video Online (Dec. 17, 2014) — Demand for ivory has claimed the lives of tens of thousands of African elephants and now a conservation report says the illegal trade is overwhelming efforts to enforce the law. Amy Pollock reports. Video provided by Reuters
Powered by NewsLook.com
Indictments in West Virginia Chemical Spill Case

Indictments in West Virginia Chemical Spill Case

AP (Dec. 17, 2014) — A grand jury indicted four former executives of Freedom Industries, the company at the center of the Jan. 9, 2014 chemical spill in Charleston, West Virginia. The spill contaminated the Elk River and the water supply of 300,000 people. (Dec. 17) Video provided by AP
Powered by NewsLook.com
Uphill Battle to Tackle Indonesian Shark Fishing

Uphill Battle to Tackle Indonesian Shark Fishing

AFP (Dec. 17, 2014) — Sharks are hauled ashore every day at a busy market on the central Indonesian island of Lombok, the hub of a booming trade that provides a livelihood for local fishermen but is increasingly alarming environmentalists. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
France's Sauternes Wine Threatened by New Train Line

France's Sauternes Wine Threatened by New Train Line

AFP (Dec. 16, 2014) — Winemakers in southwestern France's Bordeaux are concerned about a proposed high speed train line that could affect the microclimate required for the region's sweet wine. Duration: 01:06 Video provided by AFP
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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