Ask A Scientist© Weather Archive

> >>  name       Tony
> >>  status     student
> >>  age        12
>
> >>  Question - I would like to know the difference between El Nino and La
> >> Nina,
> >>what would the world weather patterns be like if El Nino and La Nina
> >>were not present. Also, what is Upwelling? Does it have something to
> >>do with warm water combining with cold water? Thank you.
>
>
>Tony,
>
>El Nino is the condition when the atmosphere and ocean
>currents cause a movement of warmer water to the eastern
>Pacific. There is kind of a snowball effect when the process
>begins that can result in severe warming of the ocean
>off the northern west coast of South America. This prevents
>water from deeper in the ocean from upwelling to the surface.
>Nutrients and food for fish do not get to the upper layer of
>ocean for food fish to eat. This causes
>fish to migrate further south, disrupting the South
>American fishing industry and causing severe drought in western
>South America. This also, usually, causes drought in the
>southwestern part and plains of North America.
>
>La Nina is the opposite condition, when warm water builds up
>in the western Pacific Ocean, often causing drought conditions
>there and leaving northern South America with floods and northern
>North America with mild, wet summers and drought in the southeastern
>United States.
>
>In between El Nino and La Nina are "normal" conditions. So, if the
>El Nino and LA Nina did not occur, we would have less variable
>weather conditions. This would be better for agriculture and
>the fishing industry, at least.
>
>David Cook
>Argonne National Laboratory
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