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Shifts in Pacific winds may support El Nino formation NASA/JPL NEWS RELEASE Posted: March 17, 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.
"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. 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 Nino. 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. 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. Topex/Poseidon is managed by JPL for NASA's Earth Science Enterprise, Washington, D.C. 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.
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Liberty Bell 7 Lost Spacecraft - the Search for Liberty Bell 7 describes the exploration of two unique and dangerous environments - space and underwater - in the recovery of Gus Grissom's Mercury capsule.Columbia Report A reproduction of the official accident investigation report into the loss of the space shuttle Columbia and its crew of seven. U.S. - U.K. - E.U. - Worldwide Mars Panorama DISCOUNTED! This 360 degree image was taken by the Mars Pathfinder, which landed on the Red Planet in July 1997. The Sojourner Rover is visible in the image. U.S. Apollo 11 Mission Report Apollo 11 - The NASA Mission Reports Vol. 3 is the first comprehensive study of man's first mission to another world is revealed in all of its startling complexity. Includes DVD!U.S. - U.K. - E.U. - Worldwide Rocket DVD If you've ever watched a launch from Kennedy Space Center, Cape Canaveral, Vandenberg Air Force Base or even Kodiak Island Alaska, there's no better way to describe what you witnessed than with this DVD.U.S. - U.K. - E.U. - Worldwide Columbia Report A reproduction of the official accident investigation report into the loss of the space shuttle Columbia and its crew of seven. U.S. - U.K. - E.U. - Worldwide Mars Panorama DISCOUNTED! This 360 degree image was taken by the Mars Pathfinder, which landed on the Red Planet in July 1997. The Sojourner Rover is visible in the image. U.S. Apollo 11 Mission Report Apollo 11 - The NASA Mission Reports Vol. 3 is the first comprehensive study of man's first mission to another world is revealed in all of its startling complexity. Includes DVD!U.S. - U.K. - E.U. - Worldwide Rocket DVD If you've ever watched a launch from Kennedy Space Center, Cape Canaveral, Vandenberg Air Force Base or even Kodiak Island Alaska, there's no better way to describe what you witnessed than with this DVD.U.S. - U.K. - E.U. - Worldwide Gemini 12 Gemini 12: The NASA Mission Reports covers the voyage of James Lovell and Buzz Aldrin that capped the Gemini program's efforts to prove the technologies and techniques that would be needed for the Apollo Moon landings. Includes CD-ROM.U.S. - U.K. - E.U. - Worldwide Expedition 20 The official embroidered patch for the International Space Station Expedition 20 crew is now available from our stores.Current Shuttle Mission Patch The official embroidered patch for shuttle Atlantis' flight to deliver critical spare equipment to the space station.![]() Ares Patch The Ares Project will develop two new rockets to launch astronauts back to the Moon under NASA's Vision for Exploration. The Ares 1 will employ a single space shuttle solid rocket booster to loft the Orion crew capsule. The gigantic Ares 5 will haul the equipment and cargo needed for such lunar voyages. This is the Ares emblem.One Giant Leap
Hosted by Corbin Bernsen, this award winning documentary marks the 50th anniversary of the U.S. space agency and features exclusive interviews with veteran astronauts.Expedition 21 The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.The web's best space video service! Get additional video, audio, image and virtual reality content for a low-cost monthly or annual subscription fee. Subscriptions start at $5.95/£3.50. Click here to see what's currently available. Hubble Posters Stunning posters featuring images from the Hubble Space Telescope and world-renowned astrophotographer David Malin are now available from the Astronomy Now Store.Get e-mail updates Sign up for our NewsAlert service and have the latest news in astronomy and space e-mailed direct to your desktop (privacy note: your e-mail address will not be used for any other purpose). Station Calendar
NEW! This beautiful 12" by 12" wall calendar features stunning images of the International Space Station and of the people, equipment, and space craft associated with it, as it takes shape day by day in orbit high above the Earth. |
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