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Link between the length of duration of El Nino and when the next El Nino occurs

  1. Jan 27, 2007 #1
    Is there a link between the length of duration of El Nino and when the next El Nino event occurs.Also,what causes the sea to get so warm during an El Nino event - is the sea heated directly by the sun,does it get heat from circulating air,or does it get heat from currents of water bringing it in?
    Can the seas become hotter because cold air or water has been moved out of a region?
  2. jcsd
  3. Jan 27, 2007 #2
    Consult some literature on El nino and la nina. There even are speculations on non-linearity of the process and chaotic behavior. Do not forget we talk about coupled processes, its not gonna be "push here and pull there" causation.

    Most of the principal qualitative features of the El Niño—Southern Oscillation phenomenon can be explained by a simple but physically motivated theory. These features are the occurrence of sea-surface warmings in the eastern equatorial Pacific and the associated trade wind reversal; the aperiodicity of these events; the preferred onset time with respect to the seasonal cycle; and the much weaker events in the Atlantic and Indian oceans. The theory, in its simplest form, is a conceptual model for the interaction of just three variables, namely near-surface temperatures in the east and west equatorial ocean and a wind-driven current advecting the temperature field. For a large range of parameters, the model is naturally chaotic and aperiodically produces El Niño—like events. For a smaller basin, representing a smaller ocean, the events are proportionally less intense. [El Niño: A Chaotic Dynamical System?
  4. Jan 27, 2007 #3

    As I understand it you have oscillations, there are either El Nino events or La Nina events, there is no middle ground (of course this is simply by definition and is based on the Southern Oscillation Index - meterological measurements made in northern Australia and Tahiti), no two events are exactly the same. These oscillations are perturbations in the ocean-atmosphere system, it is not understood whether the perturbations originate in the atmosphere or the ocean.

    During an El Nino event, a depression in the thermocline caused by anomalously high pressure in the atmosphere over Indonesia propagates eastwards along the equator as a series of Kelvin waves. Effectively the warm water travels eastwards along the equator and then spreads out along the coastline of America (and is reflected into the eastern Pacific by Rossby waves), this warm water is confined to the surface.

    During an El Nina event, the warm waters are confined to the west, this allows for more upwelling of the nutrient rich waters along the western coast of america and is associated with a richer ecosystem and better fishing.

    Yes the sea is heated by the sun
    No it doesn't get heat from circulating air, rather it loses heat to the atmosphere.
    Currents just move the heat, they neither create or destroy it.

    Theoretically yes seas can become hotter if the cold water is removed; on a side note, the reverse process happens when the faster molecules are removed by evaporation, the water cools down.
  5. Jan 27, 2007 #4
    Wouldn't the strong implications of sea currents on climate be a very strong hint to what happened during the glacial transitions?
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