Recent Shifts in Pacific Winds May Support El Nino Formation

TERRADAILY

The El Ni�o heat engine is being fired up in the west. We still are waiting to see whether the east will succumb. The east-west battle is on.

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 Nino, its little sister La Nina and the much larger and longer-lasting ocean event called the Pacific Decadal Oscillation.

Pasadena - Mar 18, 2002
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 Nino.

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 Nino 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.

TERRADAILY

El Nino Awakens

Paris (ESA) Mar 4, 2002
Four years ago, torrential rains battered the Southern US, mudslides struck in Peru -- and the inhabitants of Canada's west coast saved up to 30% on their winter heating bills. The cause? El Nino, a huge temperature shift in the Pacific Ocean which spawns climate changes globally.

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.