El Nino – Southern Oscillation - Southern Oscillation (atmosphere) - El Nino (ocean) - change in equatorial Pacific circulation - produces global climate.
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Presentation on theme: "El Nino – Southern Oscillation - Southern Oscillation (atmosphere) - El Nino (ocean) - change in equatorial Pacific circulation - produces global climate."— Presentation transcript:
El Nino – Southern Oscillation - Southern Oscillation (atmosphere) - El Nino (ocean) - change in equatorial Pacific circulation - produces global climate changes - can significantly alter weather in California Geography 104 - “Physical Geography of the World’s Oceans”
Pacific Decadal Oscillation (PDO) variations in Pacific ocean climate on decadal scales
El Nino – Southern Oscillation (ENSO) variations in Pacific ocean climate on few-year scales
The Southern Oscillation Discovered in 1928 by Sir Gilbert Walker Proposes a zonal circulation cell over the equatorial Pacific Links changes to global climate
An El Niño History late 1800s Fishermen name El Niño to the periodic warm waters that appear off the coasts of Peru and Ecuador around Christmas. 1928 Gilbert Walker describes the Southern Oscillation. 1957 A large El Niño is observed which affects not just the coasts of Peru and Ecuador but the entire Pacific Ocean. 1969 Jacob Bjerknes links the Southern Oscillation with El Niño events.
An El Niño History 1975 Wyrtki uses island sea level to show how eastward flow causes SST’s to rise in east Pacific. 1976 An idealized computer model demonstrates that winds over the far western Pacific can change SST off Peru. 1982 A severe El Niño develops unexpectedly, but is recorded in detail with newly developed ocean buoys. 1985 Several nations launch the Tropical Ocean- Global Atmosphere (TOGA) program.
An El Niño History 1986 First coupled model of ocean & atmosphere predicts El Niño event. 1988 Researchers explain how the "memory" of the ocean--the lag between a change in the winds and the response of the ocean--influences terminations of El Niño and the onset of La Niña. 1996-1997 The array of instruments monitoring the Pacific, plus coupled ocean-atmosphere models, enable scientists to warn the public of an impending El Niño event.
EL NIÑO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION issued by CLIMATE PREDICTION CENTER/NCEP/NWS 9 October 2008 Synopsis: ENSO-neutral conditions are expected to continue into early 2009. ENSO-neutral conditions continued during September 2008, as sea surface temperatures (SSTs) remained near-average in the east-central equatorial Pacific Ocean. SSTs remained slightly below-average in the central Pacific, and slightly above-average in the eastern Pacific. From west to east, the latest weekly SST index values range from −0.2°C in the Niño- 4 region to +0.3°C in the Niño 1+2 region. The subsurface oceanic heat content (average temperatures in the upper 300m of the ocean, continued to decrease in response to the strengthening of negative temperature anomalies at thermocline depth in the east-central Pacific.