Ntxw wrote:Hunabku wrote:I put together an animation to better conceptualize the connection between PDO and ENSO, via ONI which uses 3.4 region.
In the bottom area, the PDO looks 3.5 month into the future from the current date of the animation. I went with a 3.5 month PDO lag because it tracked closer to ONI than 3 or 4 months with this data set. Since we don't have October's JISAO PDO data yet, I estimated that it will stay the same as September's. On the "Lag Differential .." chart in the lower right, notice the big jump in the differential between PDO-October and ONI-June (the last big red bar).
This jump could be because of any one or a combination of the following:
1) There is something outside of ENSO teleconnection that has been recently forcing the PDO more positive
2) The PDO is showing a stubbornness to go lower which means more nino trends going forward
3) My October estimate for PDO is high, so it will actually be lower, which would better track with ONI
Also notice toward the end of the animation in November with the cold deepening in the east pacific. This seems to portend a dropping PDO, which will bring it more back in line with the temps that have dropped in ONI since July.
One thing to think about is the depth of the warm waters in the far northeastern Pacific above 40N. For the past couple of years it's not just shallow surface warmth easily shifted by the upper level pattern but consistent at depth as well. It takes a lot to upwell cooler waters with such deep warm anomalies. I think had the Nina been able to go stronger the atmosphere may have been more successful at flipping the PDO but instead the weather pattern in the northern Pacific remained similar to as if ENSO was a Nino with the deeper Aleutian low.
Anomalies at depth in the northeastern Pacific. The area you want to look at is right of 40N on this chart.
Quite warm in fact up and down the latitudes across the eastern Pacific. I posted Sept because ECMWF reanalysis does not yet have data for October.
In your typical cold PDO at depth would be colder
Wonderful thanks for this. I'd like to explore other corollaries besides Sept 2012, which was a strongly negative and entrenched PDO. If I may ask - where did you find these subsurface temp maps at?