Submitted by Nick Bone on Thu, 01/28/2016 - 16:41
Just a couple of questions about the El Nino and La Nina deal. With the northern hemisphere being in El Nino for the last couple of years, does mean that in the southern hemisphere is the opposite? The reason i ask this is because the last couple of summers down here in Vic have been somewhat tropical i.e humid and wet. Arent they also the characteristics of a La Nina effect?
Another question is there a specific cycle? Some of the people ive spoken too say its a yearly cycle but some little observation that seems incorrect. Others have said its a 5 year cycle and evena 10-20 year cycle. Im not sure personally if theres a cycle. The only the thing that comes to mind is around 05-07 we had hot dry summers and great waves (which is happening currently in north hemi?). I was a bit younger then and can't remember if it was classified as El Nino.
Lastly, does El Nino statistically or correlate with better than average waves?
Chees for any input!!
there is no cycle that i see, just random.
An El Nino event relates to sea surface temperature in the Pacific Ocean, rather than conditions in the southern or northern hemisphere. So essentially what happens to us during an El Nino, happens in reverse over on that side of the pond i.e higher rainfall along the coast of South America. An El Nino occurs when sea surface temperatues on the eastern part of the Pacific (along the South American coast) are higher than average, so you get a lot of warm, moist air rising along their coast, causing air from the central Pacific to move across to the east and fill the void left by the rising air. In a 'normal' year, these winds move in the other direction, from east to west, which brings rainfall and cloud development to Australia's east coast.
The clever people at the BOM explain it much better than me.
I guess it depends where you live in regards to the better waves. I'd imagine there would be more tropical cyclones during a La Nina event, which would benefit the east coast but i'm not from down your way so not sure what conditions produce good swell down there.
Also i'm just guessing now but I assume that because the prevalent wind direction during an El Nino is west to east, and there's more warm, moist air on the eastern side of the Pacific then there are likely to be more opportunities for significant swells to develop due to large storms or just consistent trade winds heading in their direction.
"There have been 18 La Niña events since 1900 and 12 have led to widespread wet conditions."
""JUST in time for Christmas, the weather has gifted Australia an early present with the declaration the country is now officially in the grip of La Nina.
But whether the La Nina climate driver will be a much cherished Christmas present, or the equivalent of yet another pair of socks, will depend very much on where you live.""