Sunday, August 2, 2009

Pacific Decadal Oscillation

I just saw an interesting article about the Pacific Decadal Oscillation and the El Nino-La Nina cycle. If my understanding is correct the PDO is much like a longer wavelength version of El Nino/La Nina. The shorter El Nino waves are superimposed on the longer PDO waves:




This could be good news for our water situation here in Australia. Though the PDO has been in the cold phase for a few years now and the situation isn't good. If that is the effect of climate change then around 2050 is really not going to be good here in southern Australia when the PDO is presumably back in a warm phase. Climate change predictions are for Southern and Western Australia (the Mediterranean zone) to get drier as the desert moves south. On the other hand, all the evidence I've seen indicates that during the Ice Ages this part of Australia was apparently much drier than today, which points in the opposite direction unless the Holocene has had optimal temperatures for rainfall and either hotter or colder climates are both more arid. Anyway, with our dams at around 44% capacity we can do with all the help we can get.

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