What is El Nino/La Nina & what effect do they have?

Question

Thanks.

Answer 1

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 weakended 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.

Answer 2

EL Nino is a periodical reversal of Pacific ocean currents.In a normal year,currents flow west,driven by the trade winds.In EL Nino year,the trade winds fail and warm water drifts back eastwards towards Peru.EL Nino events begin in December or January,hence its name'The Christ Child'.
La Nina occurs when equatorial waters in the Pacific become colder than normal.
Both affect the global weather.For example, Indian monsoons are influenced by them.

Answer 3

i may be bowled over if there grew to become into something in this, nevertheless i assume it won't be able to be thoroughly ruled out. i've got skimmed via your links, yet do no longer likely have the time to locate them in intensity. So, accepting that this would possibly not be the appropriate answer, my gut feeling is this has no longer something to do with ENSO, nor with international warming; anthropogenic or in any different case. if truth be told, any version interior the tidal forces over the 18 twelve months cycle would be tiny whilst in comparison with that between spring and neap tides, or certainly, the completed variety of those forces. i think of this cycle is greater possibly to be of interest to Wiccans and astrologers, fairly than climate scientists. yet even if if there grew to become right into a residual result, would not it only elementary out?