How do you explain the difference between El Nino and La Nina in laymen terms?

Question

I need a simple explanation so i can tell it to my schoolboy cousin. Thanks!

Answer 1

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Good qestion and here is the scientific answer you are looking for. When non El Nino conditions exist we find a high pressure ridge over the eastern Pacific Ocean and lower pressures over Indonesia. This gives us the typical easterlies along the equator. This condition is accompanied by upwelling and cooler ocean water in the eastern Pacific with warmer water in the western Pacific. The trades are the lower extent of what is called the Walker circulation - rising air and heavy rain over the western Pacific and sinking dry air over the eastern Pacific. When this condition I have just described in very strong an exceptionaly cool eastern Pacific is referred to as a La Nina event. The name means "the girl child".

When the high pressure ridge over the eastern Pacific weakens and the low pressure over the western Pacific is replaced by high pressure the easterlies are weakened and basically replaced by westerlies. This carries warm water eastward and the Walker circulation is reversed with heavy precipitation over the eastern Pacific and drier sinking air over the west. This describes an El Nino event. Because it is often observed around December and Christmas it was given the name "the boy child".

The upper atmosphere reflects these reversals when a ridge in the upper atmospheric flow is replaced by a trough in the east and the trough in the west is replaced by a ridge. The trough in the east now brings the heavy precipitation into the western US bringing snow to higher elevations and latitudes and rain to northern Mexico. Because there is likely to be another trough over the eastern US, there will be warmer and wetter weather there as well. With this information you can decide which event you believe is worse, El Nino or La Nina.

Source(s):

I am a retired research meteorologist with some 45 years experience.

Answer 2

one causes flood the other causes drought

Answer 3

they are the opposite of each other el nino is by caused a front of warm air, el nina is cold

Answer 4

El Nino...warmer than usual spot in the pacific
La Nina...cooler than usual spot in the pacific

Both cause fluctuations in normal weather patterns (and the effects are actually pretty similar)

Answer 5

It is hard to answer about a complex system with too simple terms. You can get a broader look at the systems by going to this site to see some of the recording being done and click on the El Nino and La Nina tab at the top. You will get links that have great details on the effects.
http://www.pmel.noaa.gov/tao/
Once you see the overview, you can put it in terms that your cousin will understand.