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El Niño and the Hawaiian Islands

El Niño and the Hawaiian Islands. Chris O’Connor UCSB – Professor Leila de Carvalho Spring 2010. El Niño.

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El Niño and the Hawaiian Islands

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  1. El Niño and the Hawaiian Islands Chris O’Connor UCSB – Professor Leila de Carvalho Spring 2010

  2. El Niño • El Niño is the warming of sea-surface temperatures in the equatorial Pacific Ocean which influences atmospheric circulation, and consequently rainfall and temperature in specific areas around the world.

  3. Madden Julian Oscillation (MJO) This weather pattern is responsible for the periodic strengthening of the anomalous westerly winds in the West Pacific which drive production of subsurface Kelvin waves, and also drive the SOI negative. 

  4. Wind Anomalies • Weaker than normal trade winds over the equatorial Pacific • Especially in the far Western Pacific to the dateline • Total Reversal of trades • West to East • Suppressed trades allows for collection of warm water near South America

  5. Kelvin Waves • Pocket of warm water traveling 150-200 meters under ocean surface • Westerly Wind Bursts • Directly related to the strength and frequency of the Active Phase of the Madden Julian Oscillation

  6. Effects of El Niño on Hawaii • Drought in Hawaii • Increase of Tropical Cyclone Activity • Increase of intensity of winter surf on northern shores

  7. Drought • October to May • Persistent • Drought is experienced on both windward and leeward sides of all islands, however to what extent is still uncertain

  8. Why Drought? • We must examine the intensification of the Hadley-type circulation in the central North Pacific due to enhanced tropical convection, and the position of Hawaii in this circulation. • Hawaii is located in the sinking portion of the Hadley cell • Convection conditions become unfavorable and drought occurs

  9. Cyclone Activity • Tropical cyclones in the vicinity of Hawaii are rare. • A change in large-scale dynamic and thermodynamic environments is believed to be conducive to the increased cyclone incidence in the vicinity of Hawaii during an El Niño year. • Cyclone tracks passing Hawaii during the El Niño batch appear to be different from those of the non–El Niño composite.

  10. El Nino Surf • LONG-RANGE NORTH PACIFIC STORM AND SWELL GENERATION POTENTIAL FORECAST* • Fall/Winter 2009-2010 Swell Generation Potential (for Hawaii) = 7.5 * www.stormsurf.com

  11. Eddie Aikau • Greg Long – 2009/2010 Winner

  12. Further Research • Windward and Leeward sides of island • A more comprehensive spatial coverage of rain gauge network is needed to account for the well known marked rainfall variations on the windward and leeward sides of the islands • Statistical analysis of weather station data

  13. Thank you.Questions?

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