2012 has ended the year with a total volume that's around 1000 km3 less than 2010 and 2011, but there's still three months to go so maybe, hopefully, the trend line will go up a bit.
Last year's melting season has convinced me that PIOMAS is doing a fairly accurate job of modelling ice volume, and so I view this data as the number one indicator of the overall health of the Arctic sea ice cover. If the 2013 trend line keeps trailing below the others, it doesn't bode well for the melting season to come. Not well at all.
Here is Wipneus'
version with the calculated "expected" 2013 values (dotted
lines), based on the same date values of 1979-2011 and an exponential
A caveat from Wipneus: "Note that the statistical error bars are quite large."
The 2012 trend line has ended slightly above the expected value. And I hadn't noticed last month, but the error bar for the 2013 minimum goes below zero, meaning there's a possibility that the Arctic reaches an ice-free state towards the end of this melting season. I somehow don't think that's going to happen, but it's interesting to see that it's possible from a statistical point of view.
I think the trend line on the PIOMAS anomaly graph has about reached its peak - on the condition that it will have the same shape as the 2010 and 2011 anomalies - just below the 1 STD zone:
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:
The 2012 trend line for average thickness is just below 2010 and 2011.
Average thickness for December 31st (in m):
- 2005: 1.52
- 2006: 1.44
- 2007: 1.41
- 2008: 1.47
- 2009: 1.40
- 2010: 1.29
- 2011: 1.25
- 2012: 1.17
The thickness graph from the Polar Science Center also has 2012 slightly below 2010 and 2011:
2013 starts with less ice than ever, but there's still plenty of time for the ice to grow thicker. Under the right conditions. PIOMAS will tell.