A while ago, crowing over the extent of Arctic sea ice this winter and the possibility this would mean loadsa ice this summer, I noted that “it is clear from that, that the winter anomaly doesn’t correlate too closely with the summer minimum”. That was based on the IJIS plot, and on little more than that the 2008 winter ice is clearly on the high side while the summer ice was on the low side. C challenged my assertion, and drew some plots, and decided in the end that maybe I was right. He was also kind enough to send me his spread sheet, but I didn’t get along with it, so have faked up my own google spreadsheet: here if you’re interested.
And the pic below, if all the googly magic works out, is a plot of the winter (March) anomaly and the summer (September) anomaly. We see what we already know: ice is declining, and 2007/8 are anomalously low. If you scatter plot the anomalies, then there is a strong relationship, because of the linear trend.
So it is more interesting to know if one year’s winter anomaly is followed by a summer anomaly. Below is a scatter plot of the winter (March) anomaly-from-linear-trend against the summer (September) anomaly-f-l-t (making the possibly unwarranted assumption that I’ve got my excel script right).
I think it is a blob. There is little sign of a relation.
All this seems vaguely interesting, and you would have thought someone must have published on it. Anyone got a ref?
Ice data from ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/Sep/N_09_area.txt and related.