More Adventures in the Arctic Oscillation

The data that I have been using is the work of Dave Thompson, and is being used by the Joint Institute for the Study of the Atmosphere and Ocean (JISAO) between the University of Washigton and NOAA.  Unfortunately, the data ends six months in to 2003.  NOAA, though, separately maintains AO data that begins in 1950 and has continued through th first four months of 2008.  For some reason, the JISAO datset lags NOAA by exactly one year, but once that is adjusted for, the two datasets fit nearly perfectly.

The large jump in the JISAO index in 2003 is not apparent at all in the NOAA dataset.  In the JISAO index, 2003 contains only six months, and although the first six months of NOAA don’t match up to JISAO, it may be that the massive monthly variability (see previous post) has effected JISAO data due to a lack of datapoints in 2003.

For this same reason, I left out 2008 from the NOAA dataset.  Altough, at this point in the year, it is trending upward.

So here is the combined record of JISAO (1900-2002) and NOAA (2003-2007).  I’ve also included a polynomial in the graph to highlight the difference between the trends in this graph and the trends in the graph presented on the JISAO site that I’ve been discussing.

And here’s the graph presented on the JISAO site once more, for comparison.


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