Last month I wrote:
The 2012 trend line isn't quite hugging the 2011 trend line as much as the latter hugged the 2010 trend line, keeping a polite distance. It's still 1069 and 1537 km3 below 2011 and 2010 respectively. Hopefully the trend line starts pulling up a bit.
Unfortunately, it seems the trend line didn't pull up and has stayed in position, still 1099 and 1136 km3 below 2011 and 2010 respectively.
Here is Wipneus' version of the same graph, for the first time with a calculated "expected" value for 2013 (dotted lines), based on the same date values of 1979-2011 and an exponential trend. A caveat from Wipneus: "Note that the statistical error bars are quite large."
The trend line on the PIOMAS anomaly graph is now well within the 2 STD zone:
Mind you, this is anomaly from the downward linear trend, not from some baseline. 2010 and 2011 showed the same behaviour, so let's see whether the current trend line will reach the 1 STD zone again.
Time now for the PICT thickness graph. I have used my crude method of dividing PIOMAS volume numbers by Cryosphere Today area numbers to calculate the ice pack's average thickness. Again, this is just an indication that allows us to compare with previous years:
Average thickness for December 1st (in m):
- 2005: 1.46
- 2006: 1.54
- 2007: 1.35
- 2008: 1.32
- 2009: 1.32
- 2010: 1.18
- 2011: 1.14
- 2012: 1.06
With CT sea ice area returning to 'normal' (see graph), meaning it's not freakishly below other years, and PIOMAS volume not returning to 'normal' (in other words: 2010 and 2011 levels), thickness will automatically be low. Maybe the rapid expansion of the ice pack in the Bering Sea is having to do with that.
The thickness graph from the Polar Science Center shows the same:
That was the last PIOMAS report for this year. Next year: new trend line, new colour, new data, new hints, new melting season.