Reader Gary posed a question regarding the relationship between wintertime freezing temperatures and teleconnection indices. Fortunately, the ESRL reanalysis site has a very handy tool for correlating temperatures or other atmospheric variables to a variety of teleconnection indices. Frankly, there are a number of indices that I have never heard of. Nevertheless, I spent about 15 minutes systematically going through each index and generating a map of the correlation between the index value and October-March surface temperatures in Alaska between 1948 and 2014. Only 'interesting' ones were included. For reference, a correlation of +1.0 indicates a perfect positive relationship and a correlation of -1.0 indicates a perfect negative (or inverse) relationship. This is the same as Pearson's "R".
The rest of the blog post is the series of maps. Since there are so many I am not going to add a figure caption to each one at this time. The automatically generated legend tells which index was used. Also, the name of the index is pretty cryptic in many instances so here is the link to the page with a description of each index: http://www.esrl.noaa.gov/psd/data/climateindices/list/
One final note, there is a difference between causation and correlation. Just because something is correlated, doesn't necessarily mean there is a cause and effect relationship (e.g., the strong negative correlation between Alaska winter temperatures and the Antarctic Oscillation). Also, there is a lot of co-variance between data. For example, the PDO index is largely reflective of North Pacific sea surface temperatures. Therefore, it is not surprising that a large pool of warm air sitting right next to Alaska will cause Alaska temperatures to be warmer than normal.
Thanks Brian for the interesting links and presentation. I'll go over it more later.ReplyDelete
Some will align themselves with either stochastic or deterministic processes, but there's no doubt chaos theory can play a modifying role in both. Now new noise has been implied via tentative Global changes to short term weather and long term climate.
Still it's nice to be able to view the overall relationship of the above indices over previous time.
Definitely a few interesting plots in there.ReplyDelete
Yes there are and the presentation is informative.ReplyDelete
Here's a recent link regarding the potential future of ENSO/Nino 1-4 described in some of the reanalysis above. Might be a good time to buy that new snow shovel if it develops and there's a connection in our future.
I wonder how this, if true, would tie into the potential for future temps and precip?
Have a look at winter 1997-98 (the time frame discussed in the link above) for temps and precip. Seems it was warm but not too much precip.
Thanks for the links Gary. Maybe Richard or I can do a blog post on the response of temperatures and precipitation to the onset of the 1997-1998 ENSO event.Delete
Thanks Brian. I'm not scheduling extra work for you folks by linking the above. I just found it interesting that NASA suggested the potential for comparable weather events associated with what initially appears to be similarities in Nino 1-4 between now and the winter of 1997-98. That's quite a prediction, but maybe they have the horsepower to do that.Delete
From your analyses in this Blog it appears theres a low to medium connection between temps in certain parts of Alaska and the ENSO index. Precip may not correlate as strongly with that distant pattern.
The positive and negative correlations in the above indices are very interesting. It'll be fun to follow through during the next 12 months and see what evolves.