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El Nino-What exactly is it?

The term El Nino means ‘Christ Child’ and was first used by Peruvian fishermen in the late 1800’s to describe the warm current appearing off the western coast of Ecuador and Peru around Christmas time.

Meteorologically, El Nino describes the warm phase of a naturally occurring sea surface temperature oscillation in the tropical Pacific Ocean. When this warming occurs the usual upwelling of cold, nutrient rich deep ocean water is significantly reduced.
Sometimes an extremely warm event can develop that lasts for much longer time periods.

The summer season of 1982-83 and 1997-98 were strong El Nino conditions in New Zealand with very warm and dry conditions in some northern and eastern areas of the country, resulting in drought conditions.

The El Nino term was also used for this summer but it hasn’t been quite so severe as mentioned in the years above.

– Weather Analyst Richard Green


Ken Ring on 7/03/2010 11:09am

But if you dig further into history you’ll find it’s not new. Peruvian farmers have records of El Ninos 15,000 years ago. The moon causes the oceans’ oscillations because currents cancel each other every 4.5 years which is a quarter of the tidal cycle, and seawater level in the Pacific tips to the west until there is a 62cm sealevel difference, then, just the water in your bath, back to the east, like the sloshing in a dish. Winds are caused by the direction of surface currents, which is why we get easterlies in La Nina and westerlies in El Nino. But as to LN or ENs, meteorologists only call off on them when the year is over. First, when the Darwin/Tahiti sea temperature difference switches, they are called El Nino "conditions", then if they come about they are called El Nino "episodes". If they didn’t happen, they protect the earlier forecast and say it was an EN but it was "a fizzer". That is why you can get both wet and dry El Ninos and wet and dry La Ninas. We should just stick with the oscillations instead of trying to make it too complicated for ordinary folk to understand. In simple terms, it is a 3-yr system. You get a sunspot minimum year (2009), followed by El Nino (2010), followed by a year for tropical cyclones (2011). For instance, you’ll notice that TCs have become slightly more active this year than last year. And next year, when lunar perigee matches eastern declination TC’s will start to peak. It’s nature and it’s cyclic. Sadly many meteorologists seem to be more interested in setting up fancy equipment that can identify anomalies, rather than studying weather basics and cycles. Ken

RW on 7/03/2010 11:14pm

I suggest readers look at this analysis, which is updated weekly. It is perfectly clear that the ENSO cycles do not repeat in a clockwork fashion, and the timings are quite variable. If it was a simple as implied above, nobody in meteorological science could possibly niss it. The allegations about switching names are nothing more than straw-man setups, and the criteria for the onset and ending of episodes are quite clearly described in this link.

Anyone who reads this can see the variability, both in duration and intensity.

Ken Ring on 9/03/2010 12:31pm

Well, RWood, weekly is no good, too short term. Of course that will show variability, but that’s not what we’re talking about. El Nino doesn’t come and go weekly as you seem to suggest.
If you really wish to see the cyclic nature of the pattern EN/LN longterm, look at this page
Oh, and by the way, meterologists do miss things.
Oh and another by the way, the EN “condition” vs “episode” that I referred to, was the subject of a presentation by the head CSIRO meteorologist at a Victorian Climate Conference for farmers that I attended about 3 years ago.
Ken Ring

Guest on 7/03/2010 3:24am

El nino is spanish for boy. La nina is spanish for girl. Nothing to do with Christ.

RW on 7/03/2010 9:23am

Nino/Nina do refer primarily to young children, and because of the Christmas timing they were indeed referring to the Christian birth celebration – they were devout Catholics and attached a good deal of significance to the events.

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